Course Introduction - Spring 2022

Resources

• Slides
• Previous Versions

Video Script

[Slide 1]

Hello and welcome to the Computational Core program!

My name is Emily Alfs-Votipka, and I’ll be one of the instructors for this program. My contact information is shown here, and is also listed on the syllabus.

[Slide 2]

There are many other instructors and TAs for this program that you may interact with or see in the tutorial videos. They all have been instrumental in the development of this program.

[Slide 3]

In this course we will primarily use a K-State email group (cc110-help or cc110-help@ksuemailprod.onmicrosoft.com ) to communicate. Email sent to this address is forwarded to all instructors and TAs. Our replies to you will also be shared amongst the instructors and TAs so we all have access to the assistance you have already received. We will respond to you within a business day So a question emailed Friday night may not receive an answer before Monday.

If you wish to pose a discussion topic to you classmates, you should use the discussion feature in Canvas. Please note that asking a question on a discussion forum is not the same as emailing cc110-help; we will certainly monitor the discussion channels, but not with the same speed as the “help line”. Please read and adhere to the guidance on Netiquette in the syllabus for all electronic communications.

[Slide 4]

In addition to email and Canvas, we’ll be using the online learning platform Codio for most of the programming tutorials and projects in this program. We’ll also discuss how to use Codio later in this module.

[Slide 5]

The Computational Core program consists of several courses, and each course contains a number of learning modules. There are about 30 modules in this course. Each module will usually consist of some lecture material and quizzes, and there are a few modules which include a programming component. The modules themselves are gated, which means that you must complete each item in the module in order before continuing. In addition, the modules enforce prerequisite requirements from other modules. For CC 110 you must complete them in order starting with module 0, the enroll module should be completed first, but is not a prerequisite.

You are welcome to work on this course at any time during the week as your schedule allows, provided that you complete each module before the listed due date. There will be roughly two modules due each week. The modules are self-contained, and nearly all of the grading in this course is completed automatically through Canvas and Codio. So, you can complete modules at any time before the due date, and once a module is complete, you may immediately start on the next one.

[Slide 6]

Looking ahead to the rest of this introductory module, you’ll see that there are a few more items to be completed before you can move on. In the next video, we’ll discuss a bit more information about navigating through this course on Canvas and using the Codio learning environment.

[Slide 7]

One thing we highly encourage each of you to do is read the syllabus for this course in its entirety, and let us know if you have any questions. My view is that the syllabus is a contract between me as your teacher and you as a student, defining how each of us should treat each other and what we should expect from each other. We have made a few changes to the standard syllabus template for this program, and those changes are clearly highlighted. Finally, the syllabus itself is subject to change as needed as we adapt this program to meet the needs of its students, and all changes will be clearly communicated to everyone before they take effect.

[Slide 7]

One very important part of the syllabus that every student should read is the late work policy. First off, each module has a due date, and you may work on that module at any time before it is due, provided you have met the prerequisites. As discussed before, you must do all the readings and assignments in a module in listed order before moving on, so you cannot jump ahead. A module is considered completed when all items have been completed.

For the purposes of grading, we will use the date and time that the confirmation quiz was submitted at the end of each module to determine when the module was completed. This is due to the way that Codio handles automated grading, as it may resubmit previously graded assignments if an error in the module is corrected, making a previously completed assignment appear to be submitted late.

If any work is submitted after the due date, a penalty of 10% of the total points possible in that assignment will be deducted for each day it is late, up to a maximum of 3 days. After 3 days beyond the due date, you will receive a 0 on the assignment. Please refer to the full late policy in the syllabus for more information about how late work is handled in this course.

Finally, even if a module is late, it still must be completed before you can move on to a later module. So, it is very important to avoid getting behind in this course, as it can be very difficult to get back on track. If you ever find that you are struggling to keep up, please don’t be afraid to contact either the instructors or GTAs for assistance. We’d be happy to help you get caught back up quickly.

In this program, the standard “90-80-70-60” grading scale will apply, though I reserve the right to curve grades up to a higher grade level at my discretion. Therefore, you will never be required to get higher than 90% for an A, but you may get an A if you score slightly below 90% if I choose to curve the grades.

This is intended to be a completely online, self-paced course. There are no mandatory scheduled course times. All of the content is available online, so you can work whenever and wherever you want. It could be a 3-hour block once a week, or a few minutes here and there between classes. It’s really up to you and your schedule. However, remember that each module may require 4 to 6 or more hours of work to complete, so make sure you have plenty of time available to devote to this course.

Also, a vast majority of the grading in this course will be handled automatically through Canvas and Codio. This means that you’ll be able to receive feedback directly from those systems as soon as you submit your work. You may also contact the instructors and GTAs for additional tips and feedback regarding your work, but depending on the number of students in the program, we may not be able to review every student submission directly.

In addition, due to the flexible online format of this class, there won’t be any long lecture videos to watch. Instead, each module will consist of a guided tutorial and several short videos, each focused on a particular topic or task. Likewise, there won’t be any textbooks required, since all of the information will be presented in the interactive tutorials through Codio. Finally, since we are using Codio as our learning platform, you won’t have to deal with installing and using a clunky integrated development environment, or IDE, just to learn how to program. Codio helps make learning to program quick and painless by moving everything to the web.

For this course, the only supplies you’ll need as a student are access to a modern web browser and a broadband internet connection. No other special hardware or software is necessary!

Finally, as you are aware, this course is always subject to change. This is a relatively new program here at K-State, and we’re always working on new and interesting ideas to integrate into the courses. The best advice I have is to look upon this graphic with the words “Don’t Panic” written in large, friendly letters. If you find yourself falling behind, or not understanding seek our help via cc110-help.

So, to complete this module, there are a few other things that you’ll need to do. The next step is to watch the video on navigating Canvas and Codio, which will give you a good idea of how to most effectively work through the content in this course.

To get to that video, click the “Next” button at the bottom right of this page.

Navigating Canvas & Codio

Resources

• Codio Documentation

Video Script

This course makes extensive use of several features of Canvas which you may or may not have worked with before. To give you the best experience in this course, this video will briefly describe those features and the best way to access them.

When you first access the course on Canvas, you will be shown this homepage. It contains quick links to the course syllabus and Piazza discussion boards. This is handy if you just need to jump to a particular area.

Let’s walk through the options in the main menu to the left. The first section is Modules, which is where you’ll primarily interact with the course. You’ll notice that I’ve disabled several of the common menu items in this course, such as Files and Assignments. This is to simplify things for you as students, so you remember that all the course content is available in one place.

When you first arrive at the Modules section, you’ll see all of the content in the course laid out in order. If you like, you can minimize the modules you aren’t working on by clicking the arrow to the left of the module name. I’ll do so, leaving the introductory module open.

As you look at each module, you’ll see that it gives quite a bit of information about the course. At the top of each module is an item telling you what parts of the module you must complete to continue. In this case, it says “Complete All Items.” Likewise, the following modules may list a number of prerequisite modules, which you must complete before you can access it.

Within each module is a set of items, which must be completed in listed order. Under each item you’ll see information about what you must do in order to complete that item. For many of them, it will simply say view, which means you must view the item at least once to continue. Others may say contribute, submit, or give a minimum score required to continue. For assignments, it also helpfully gives the number of points available, and the due date.

Let’s click on the first item, Course Introduction, to get started. You’ve already been to this page by this point. Many course pages will consist of an embedded video, followed by links to any resources used or referenced in the video, including the slides and a downloadable version of the video. Finally, a rough video script will be posted on the page for your quick reference.

While I cannot force you to watch each video in its entirety, I highly recommend doing so. The script on the page may not accurately reflect all of the content in the video, nor can it show how to perform some tasks which are purely visual.

When you are ready to move to the next step in a module, click the Next button at the bottom of the page. Canvas will automatically add Next and Previous buttons to each piece of content which is accessed through the Modules section, which makes it very easy to work through the course content. I’ll click through a couple of items here.

At any point, you may click on the Modules link in the menu to the left to return to the Modules section of the site. You’ll notice that I’ve viewed the first few items in the first module, so I can access more items here. This is handy if you want to go back and review the content you’ve already seen, or if you leave and want to resume where you left off. Canvas will put green checkmarks to the right of items you’ve completed.

Continuing down the menu to the left, you’ll find the usual Canvas links to view your grades in the course, as well as a list of fellow students taking the course.

===

Now, let’s go back to Canvas and load up one of the Codio projects. To load the first Codio projects, click the Next button at the bottom of this page to go to the next part of this module, which is the Codio Introduction tutorial. On that page, there will be a button to click, which opens Codio in a new browser window or tab.

Once Codio loads, it should give you the option to start the Guide for that module. You’ll definitely want to select that option whenever you load a Codio project for the first time.

From there, you can follow the steps in that guide to learn more about the Codio interface. The first page of the guide continues this video. I’ll see you there!

Where to Find Help

Resources

• Slides
• K-State IT Help Desk - Email helpdesk@ksu.edu
• K-State Online Canvas Help
• Instructure Canvas Guides
• Codio Documentation
• Codio Support
• K-State Libraries
• K-State CS Support
• K-State CS Advising
• K-State Engineering Student Services
• K-State Office of Student Life
• K-State Report It

Video Script

[Slide 1]

As you work on the materials in this course, you may run into questions or problems and need assistance. This video reviews the various types of help available to you in this course.

[Slide 2]

First and foremost, anytime you have a questions or need assistance in the Computational Core program, please email the appropriate help group. It is the best place to go to get help with anything related to this program, from the tutorials and projects to issues with Codio and Canvas. For example, if you are enrolled in CC315 and have questions, from your KSU email, you would type cc315-help and hit tab to auto-complete the email.

[Slide 3]

If you have any issues working with K-State Canvas, K-State IT resources, or any other technology related to the delivery of the course, your first source of help is the K-State IT Helpdesk. They can easily be reached via email at helpdesk@ksu.edu . Beyond them, there are many online resources for using Canvas, all of which are linked in the resources section below the video.

[Slide 4]

If you have any issues using the Codio platform, you are welcome to refer to their online documentation. Their support staff offers a quick and easy chat interface where you can ask questions and get feedback within a few minutes.

[Slide 5]

If you have issues with the technical content of the course, specifically related to completing the tutorials and projects, there are several resources available to you. First and foremost, make sure you consult the vast amount of material available in the course modules, including the links to resources. Usually, most answers you need can be found there.

Of course, as another step you can always exercise your information-gathering skills and use online search tools such as Google to answer your question. While you are not allowed to search online for direct solutions to assignments or projects, you are more than welcome to use Google to access programming resources such as StackOverflow, language documentation, and other tutorials. I can definitely assure you that programmers working in industry are often using Google and other online resources to solve problems, so there is no reason why you shouldn’t start building that skill now.

[Slide 6]

Next, we have grading and administrative issues. This could include problems or mistakes in the grade you received on a project, missing course resources, or any concerns you have regarding the course and the conduct of instructors and your peers. Since this is an online course, you’ll be interacting with us on a variety of online platforms, and sometimes things happen that are inappropriate or offensive. There are lots of resources at K-State to help you with those situations. First and foremost, please email your instructor as soon as possible and let them know about your concern, if it is appropriate for them to be involved. If not, or if you’d rather talk with someone other than your instructor about your issue, I encourage you to contact either your academic advisor, the CS department staff, College of Engineering Student Services, or the K-State Office of Student Life. Finally, if you have any concerns that you feel should be reported to K-State, you can do so at https://www.k-state.edu/report/ . That site also has links to a large number of resources at K-State that you can use when you need help.

[Slide 7]

Finally, if you find any errors or omissions in the course content, or have suggestions for additional resources to include in the course, email the instructors. There are some extra credit points available for helping to improve the course, so be on the lookout for anything that you feel could be changed or improved.

[Slide 8]

So, in summary, the content and links in the modules should always be your first stop when you have a question or run into a problem. For issues with Canvas or Codio, you are also welcome to refer directly to the resources for those platforms. For questions specifically related to the projects, use the courses help group. For grading questions and errors in the course content or any other issues, please email the instructors for assistance.

Our goal in this program is to make sure that you have the resources available to you to be successful. Please don’t be afraid to take advantage of them and ask questions whenever you want.

What You'll Learn

Resources

• Slides
• Code.org Quotes

Video Script

Finally, before embarking on this program, let’s take a brief minute to review what you’ll learn by the time you complete the program.

Of course, the biggest and most impactful outcome will be learning how to write computer programs. Throughout the Computational Core program, you’ll learn either the Java or Python programming language, and get to a point where you are quite proficient with your language of choice. You’ll be capable of building your own programs from scratch to meet many of the challenges you’ll encounter in your career or elsewhere. This skill alone will set you well above your peers.

There are many additional benefits beyond just learning how to write programs. For starters, programming involves a large amount of problem solving and computational thinking, and these courses will help sharpen you skills in both areas. In addition to programming, you’ll also learn about software engineering methods that will help you build better programs, but also data structures and algorithms that will make your code more efficient and useful as it manipulates and stores data. Of course, you’ll also pick up some new math and logic skills, as both are vitally important to understanding computer code. Lastly, we’ll spend a bit of time discussing how computers actually work, so you can see how your code actually gets a computer to perform the tasks you desire.

Finally, you may be asking yourself why this is important. I could absolutely bring out large numbers of statistics stating how many computer programming jobs are available right now, and how we have a distinct lack of capable graduates to fill these positions. I could also talk about how much more money you could make as a computer programmer than in many other fields. But, instead, I think it is best to just present this quote from Stephen Hawking, one of the most brilliant people to ever live:

Whether you want to uncover the secrets of the universe, or you just want to pursue a career in the 21st century, basic computer programming is an essential skill to learn. - Stephen Hawking

This is just one of the many great quotes encouraging you to learn computer programming from Code.org. I highly recommend checking out their quote archive whenever you need additional inspiration.

That should cover all of the background information you’ll need before you start this program. The rest of this module includes the full course syllabus and a few assignments that you should read through before beginning the course, but you don’t have to do anything else for them right now. Finally, this module wraps up with a quick quiz making sure you are 100% ready to take this course.

Best of luck to you on your adventure through this program!

How to Learn Programming

Resources

• Slides
• The Science of Learning Programming from Nathan Bean’s CIS 400 Textbook
• The Power of Believing You Can Improve | Carol Dweck - TED Talk on Mindsets and the Power of “Yet”
• The New Science of Learning: How to Learn in Haromony with your Brain by Terry Doyle and Todd Zakrajsek - Great Book on Learning
• Constructivism on Wikipedia - Article about Jean Piaget’s Learning Philosophy
• Toward a Developmental Epistemology of Computer Programming by Raymond Lister - Introduces the Stages of Learning to Program

Video Script

Before we launch into the course itself, I wanted to take a few minutes to share some information with you regarding what we know about how students learn to program. This isn’t just anecdotal evidence from computer science teachers like me, but theories and research from education researchers who study how humans learn new skills and abilities throughout their lives.If I had to summarize all of this information in as few words as possible, I’d simply say “do the work.” Learning to program is difficult, and the only way to really get good at it is through constant practice and learning. However, that greatly oversimplifies the information that I want to share, and I’m hoping that you’ll find some helpful takeaways from this video that you can incorporate into your learning process.

Before I begin, I want go give all the credit to Nathan Bean for developing this information as part of his CIS 400 course. He graciously allowed me to use his hard work here, and I encourage you to check out his original version, which is available at the URL shown on this slide.

The statement “do the work” is a shorter version of a very common quote from educators, which is “the person doing the work is the person doing the learning.” I couldn’t find a solid reference for who said it first, so I’ll just attributed it to various educators throughout time. This really highlights one of the biggest struggles many students run into when learning to program. There are so many guides online, and the answer to many simple problems can be found through a quick Google search. You can just copy and paste the code, and then your program works. However, did you really learn how to write that program and what it does, or just how to find a quick answer? While this may be a useful tactic from time to time, if you rely too much on other people to do your coding, you really won’t learn it yourself. This is just like learning to shoot free throws on a basketball court or beating your best time in a speedrun - you can’t just watch someone do it and expect to do it yourself (believe me, I’ve tried). So, if you aren’t doing the work, you aren’t really learning.

Next, let’s address a major myth in computer science. I’ve heard this many times: “some people are just natural born programmers, and others simply cannot learn to program.” And yes, on the surface, it may appear to be this way. Some students just seem to have a knack for programming, and you may sit and struggle and not really get anywhere. However, there is no innate skill or ability that makes you good at programming.

Instead, let’s reframe what it means to learn programming. At its core, programming is learning to write steps to solve problems in a way that a computer can perform those steps. That’s really what we are doing when we learn programming.

So, we must focus on learning how to write those steps with the proper exactitude and precision so that they make sense, and we must understand how a computer functions to be able to program that computer effectively. So, when you see someone who is good at programming, it’s not because they are good at some esoteric skill that you’ll never have - they just know how to express their steps properly and know enough about how a computer works to make their program do what they want. That’s really it! And, to be honest, after a single semester of learning to program, you’ll have all the skills you need to do both of those things! If you know how to make conditionals, loops, functions, and use simple variables and arrays, that’s really all you need. Everything else that comes after that is just refining those skills to make your programs more powerful and your coding more efficient.

So, how do we learn these skills? Well, there are a couple of important pieces we need to make sure are in the right place first. For starters, we need to have the correct mindset. Many times I’ll see students struggle to learn how to program, and they’ll say things like what you see on this slide. “Its too hard.” “I don’t understand this.” “I give up.” Statements like this are the sign of a “fixed mindset,” and they can be one of the greatest blockers preventing you from really learning to program. Just like learning any other skill, you have to be open to instruction and willing to learn, or else you’ve failed before you even started.

Instead, we want to focus on building a growth mindset. In the TED talk by Carol Dweck that is linked below this video, which I encourage you to watch, she talks about the power of “yet.” We can turn these statements around by simply adding positive power of “yet” - “I don’t understand this yet.” “I love a good challenge.” “I’ll keep trying until I get it.” Going into a programming project with a mindset that is open to growth and change is really an important first steps. When I feel like I’m getting a fixed mindset, I like to think about how difficult it would be to teach a child to tie their shoes if they don’t want to learn. As soon as I realize that, it is pretty easy to recognize that same problem in myself and work to correct it.

So, once we have our growth mindset, how do we actually learn to program? To understand that, let’s dive a bit into the world of educational theory and the work of Jean Piaget. Piaget was a biologist and psychologist who studied how young children acquired new knowledge, and he helped pioneer the concept of Constructivism, one of the most influential philosophies in education. You can read more about Constructivism in the links below this video.

One particular thing that Piaget worked on was a theory of genetic epistemology. Epistemology is the term for the study of human knowledge, so genetic epistemology is the study of the origins, or genesis, of that knowledge. Put more clearly, it’s the study of how humans create new knowledge. This concept was inspired by research done on snails - he was able to prove that two previously distinct species of snails were actually the same by moving snails from one habitat to another and observing how they modified their behaviors and how their shells grew to match the snails in the new habitat. Put clearly, the snails displayed an altered behavior based on their environment. They tried to exist in equilibrium with their environment by adapting their behaviors to fit what they now experienced in the word.

Piaget suspected that something similar happens when humans try to learn something - the brain tries to adapt itself to maintain an equilibrium in its environment, which in this case is the existing knowledge it contains. So, when the brain is exposed to new ideas, it must somehow adjust to account for that new information. Piaget proposed two different mechanisms for how this occurs: assimilation and accommodation. In assimilation, new knowledge can be added to existing structures in the brain. For example, if you are exposed to a new color, such as periwinkle, you can see that it falls somewhere between blue and violet, two colors you already know. So, you can assimilate that new knowledge into the existing knowledge without a major disruption to your mental structure of existing colors. Accommodation, on the other hand, happens when your brain must radically adapt to new information for which no existing structures exist. This can be very difficult, and can lead to a lot of struggle and frustration when trying to get “over the hump” on a new subject. Think about learning algebra or a new language for the first time - you really don’t have anything you can use to help understand this new material, so you just have to keep at it until those new structures are formed in your brain.

Unfortunately, to achieve accommodation, your brain simply has to build brand new structures to store and represent all of this new information, and that process is difficult and takes time. Put another way, it takes significant stimulus, usually in the form of doing homework, struggling with difficult problems and wrestling with the new information to try and understand it all, to create enough disequilibrium in your brain that, coupled with a growth mindset, will allow accommodation to occur. However, when all the pieces are in the right place, and you work hard and have a growth mindset, then…

EUREKA! The structures will form, and you’ll get over that huge hurdle, and things will start falling into place. It may not happen all at once, but it does happen (you’ve probably had it happen to you several times already - think about some eureka moments from your past - were they related to learning a new skill?). Of course, there’s a good chance that your brain might form a few incorrect structures in the process, so you’ll have to overcome those as you continue to learn. I still struggle to spell some words because my brain formed incorrect structures when I was still learning. But, if you continue to work hard and be open to learning, you’ll eventually sort those errors out as well.

Let’s look at one other concept in education, which is called stage theory. Piaget identified four stages that children go through as they learn to reason about the world. Those four stages are shown on this slide. In the sensorimotor stage, the child is just using their senses to interact with the world, without any real understanding of what will happen when they perform an action. This is best represented by babies and toddlers, who touch and taste everything in their surroundings. Next, the preoperational stage is represented in young children as they start to think symbolically about the world, using pictures and words to represent actions and objects. They then progress to the concrete operational stage, where they can begin to think logically and understand how concrete events happen. They can also start to think inductively, building the general principles of the world from their specific experiences. For example, if they observe that cooked spaghetti is better than raw spaghetti, they might reason that other foods like potatoes are better cooked than raw. Finally, the last stage is the formal operational stage. This stage is represented by the ability to work fully with an abstract work, formulating and testing hypotheses to truly understand how the world works and predict how new items will work before experiencing them firsthand.

Many later researchers built upon this model to show that adults learn in much the same way. They also discovered that the stages are not rigid, and you may exhibit behaviors from multiple stages at any given time. This is called the “overlapping waves” model, and is shown here in this diagram. So, as you learn new skills, you may be at the operational stage in some areas, but still at the preoperational stage in other areas. This explains why some concepts may make sense while others don’t for a while - you just have to keep going until it all fits together.

So, how can we apply all of this information to programming? One theory comes from the work of Lister and Teague, who proposed a developmental epistemology of computer programming. Put another way, they applied this theory to computer science education, and gave us a unique way to think about the different stages of learning to program.

At the sensorimotor stage, we’re just getting the basics. So, when given a piece of code and asked to trace what it does, we still make lots of errors and get the answer incorrect. If we want to get a program to work ourselves, it usually involves a lot of trial and error, and many times when it does end up working we don’t even know exactly why it worked that time, but we’re building up a baseline of information that we can use to construct our mental model of how a computer works.

As we progress into the preoperational stage, we become better at tracing code correctly, but we still struggle to understand what the program itself does. We see each line of code as a separate instruction, but not the entire program. A great analogy is reading a recipe that calls for flour, water, salt, and yeast. Will it make bread? Biscuits? Pie crust? We’re not sure yet, but at least we can recognize the ingredients. To solve problems at this stage, we typically will randomly adjust pieces of our code that we don’t quite understand and see what it does, trying to form a better idea of the importance of each line in the code.

Eventually, we’ll get to the concrete operational stage. At this stage, we can construct our own programs, but many times we are simply piecing together parts that we’ve used before and performing some futile patches and bugfixes as we refine the program. We can also work backwards to figure out what a program does from execution results, but we still aren’t very good at deducing the results from the code itself. However, we’re starting to work with abstraction, though we tend to simplify things to a level that we are more comfortable with.

Finally, we’ll reach the formal operational stage. At this stage, we can comfortable read and understand code without executing it, quickly seeing what it does and how it works without fully tracing it ourselves. We can also start to form hypotheses for how to build new programs and code, and reason about whether different approaches would work better or worse than others. This is the goal stage for any programmer! Once you have reached this stage, then you’ll feel totally at home working in code and developing your own programs from scratch.

So, how can we enable ourselves to be the best learners we can be? There is lots of interesting research in that area, best summarized in the book “The New Science of Learning” that is linked below this video. Let’s go through a few of the big concepts.

First, getting ample and regular sleep is important, because it allows your brain to build those knowledge structures we discussed earlier and store the memories from the day in long-term storage. Without enough sleep, your brain is unable to process memories offline and make them ready for retrieval later on, an important step in learning. Also, consuming large amounts of caffeine or alcohol can disrupt your sleep patterns, so keep that in mind before you pour that next cup of coffee or go out partying. You can also take advantage of modern technology to help you track your sleep - most smart watches and smartphones today can help with that!

Likewise, regular exercise is important to both your physical and mental health. When you exercise, especially aerobic exercise that gets your heart rate up, your body releases neurochemicals that help your brain cells communicate. In addition, just getting up and moving around regularly helps keep your body healthy, so take regular breaks, and consider getting a standing desk for some extra benefits.

Research also shows that engaging your senses is an important part in learning. This is why we, as teachers, try to vary our lessons with pictures, videos, activities, and more. It is also the basis of the cognitive apprenticeship style of learning that we use, which you can learn more about in the links below this video. We show you the code we are writing, engaging your sense of vision, while talking about it so you are also listening, and then you are writing your own version, using your sense of touch. You can build upon this by using your senses while you learn by taking notes during a lecture video, building concept maps, and even printing out and writing on your code and these lecture scripts. All of these processes help engage different parts of your brain and make it that much easier to build new knowledge structures.

Looking for patterns is another important way to understand programming. There are many common patterns in computer programs, such as using a for loop to iterate through an array, or an if-else statement to determine if a particular variable is set to a valid value. By recognizing and understanding those patterns, we can more quickly understand new programs that use slightly different versions of the same code. Humans are naturally very good at pattern recognition, and it is one of the reasons why we see the same code structures time and time again - not because they are the only way to accomplish that goal, but because that structure is commonly used across many programs and therefore is easier to understand.

There is quite a bit of research into how memories are formed and how we can adjust our studying habits to take advantage of that. For example, cognitive science shows that the parts of our brain responsible for memory creation are active up to one hour after a learning experience has ended, such as a lecture video or activity. So, instead of jumping to the next task, you may want to take a little while to reflect on what you just did and let it sink in before moving on. Likewise, to build strong memories, it is important to constantly recall the memory or use the skills you’ve learned to strengthen their structures in the brain. This is why teachers like to throw in a few questions from a previous exam or quiz every once in a while - it helps strengthen those structures by forcing you to recall information you’ve learned previously. On the other hand, many students try to “cram” a bunch of information right before an exam, only to forget it soon after because it wasn’t recalled more than once. As you progress further, we’ll continue to come back to concepts you’ve already learned and build upon them, a process called elaboration that helps reinforce what you’ve already learned while building new, related knowledge.

Finally, it is important to remember that we must give our brains the space it needs to focus on the task at hand. Multitasking while learning, such as watching YouTube or Twitch, chatting with friends, or listening to a lecture video while coding can all reduce your brain’s ability to form strong memories and do well. In fact, research shows that individuals who try to multitask tend to make 50% more errors and spend 50% more time on both tasks. So, instead of giving yourself distractions, try to find things that will help you focus better - there are some great playlists online for music without lyrics that can help you focus or code better, and you can easily mute notifications on your phone and on your computer for an hour or so while you work.

So, let’s summarize what we’ve covered here. First, and most importantly, remember that you can learn to program, just like the many students who have done it before you. However, it can be difficult and frustrating at times, and it will take lots of hard work on your part to make it happen. That means that you’ll need to read and write a lot of code before it really starts to make sense. In short, you must do the work to learn to program.

That said, you can help make the process easier by getting good sleep, exercising regularly, and engaging fully with all of the content in the course. That means you’ll need to take your own notes, maybe draw some diagrams, and annotate code you write and code you read to help you understand it. While you are working, try not to multitask so you can focus. If you are given some code to include in your program, don’t copy/paste it - rewrite it, and make sure you completely understand what each line does. Finally, take some time to read code written by others! GitHub is a great place to discover all sorts of code and see how others write code. If you want to write good poetry you have to read lots of good poetry, and the same goes for coding.

With that in mind, I hope you are able to make the best of this course and continue to develop your programming skills. If you are interested in this topic and would like to know more about things you can do to be a better learner, let us know! As you can imagine, teachers like me love to talk about this stuff, so don’t be afraid to ask. Good luck!

CC 210 Syllabus - Spring 2023

CC 210 - Fundamental Computer Programming Concepts

Previous Versions

Instructor Contact Information

• Instructor: Emily Alfs-Votipka (emilyalfs AT ksu DOT edu)
  I use she/her pronouns. Feel free to share your own pronouns with me, and I’ll do my best to use them!
• Office: DUE 2161

• Office Hours: M/W 1:00-3:00
  • Want to meet with me outside of my regular office hours? https://calendly.com/emilyalfs

Preferred Methods of Communication:

• Email: Please use “cc210-help” (cc210-help@ksuemailprod.onmicrosoft.com if not on web-mail) for all communication regarding these courses as it allows instructors and TAs to provide a clear and detailed response, as well as easily store and record communication for reference later. You should receive a response within one business day, and hopefully much sooner. Note emailing the instructor or teaching assistants directly may result in longer wait times for your support.

Teaching Assistants and Office Hours

All TA office hours will be held in DUE 1118A and have the ability to join virtually: https://officehours.cs.ksu.edu/ Email CC210-help for assitance with the queue

How to Get Help in this Course

You are encouraged to seek help whenever you feel you are being overwhelmed or don’t understand a topic. You are not alone! The instructors and TAs are always willing to help students with any questions you may have about the class or other issues related to Computing Science. So please, don’t be afraid to ask questions. Get help early and often!

Here are the 4 recommended ways to get help on CC 210:

• Review the course materials posted on K-State Canvas and the course website
• Send assignment questions to the CC 210 Help email (cc210-help@ksuemailprod.onmicrosoft.com )
• Visit your professor’s office hours, or the office hours for your TA if available
• Schedule a one-on-one meeting with your professor/TA

Prerequisites

• C or better in CC 110 - Introduction to Computing (Prerequisite or Concurrent Enrollment with instructor permission)

Course Overview

Basic concepts in developing computer programs: program structure and syntax, primitive data types, variables, control flow, iteration, simple algorithms, debugging, and good software development practices. Introduction to object-oriented programming.

Course Description

The course introduces students to computer programming using one of several programming languages. Interactive lessons and engaging projects reinforce new skills and concepts while relating programming fundamentals to the real world. This course covers the basic concepts of programming, from variables and control flow to functions, objects, and simple algorithms.

Learning Objectives

In either Java or Python (J or P), successful students should be able to:

1. Evaluate data requirements to create variables, use operators and call/create functions for: strings, integers, real numbers and Boolean values.
2. Understand the creation and use of mono-typed Lists (P) or Arrays (J) and their common built in methods and attributes.
3. Analyze and adapt string methods to split, join and extract sub-strings to solve problems.
4. Understand how code written by them may throw exceptions
   1. Understand how to create new exceptions
   2. Understand and adapt exception handling structures
5. Understand how to create programs that read-from and write-to text files.
6. Analyze and create conditional statement to control program execution
7. Analyze and create loops to control program execution
8. Analyze and adapt methods/function to control program execution
   1. Remember to consider separation of concerns when creating methods
9. Understand how to create instance-based classes to include
   1. public/private access of components
   2. attributes, properties and methods
   3. inheritance
10. Understand how to adapt Boolean equations to common natural language problem statements
11. Understand how to adapt class APIs to incorporate objects in solutions
12. Analyze medium-to-low-level designs expressed as text-based program requirements to create programs including: UML Class diagrams, flow charts and pseudo code
13. Create terminal or console based programs

Major Course Topics

• Programming Basics
• Primitive Data Types
• Boolean Logic and Boolean Algebra
• Conditional Statements
• Loops
• Arrays / Lists
• Strings, String Parsing, and String Formatting
• Exception Handling and Debugging
• Console and File I/O
• Methods, Arguments and Parameters
• Classes and Objects
• Object-Oriented Programming
• Model-View-Controller Architecture
• Inheritance and Polymorphism
• Standard Library/Module Collections and generic types

Course Structure

This course is intended to be taught 100% online, each module is self-paced, and each module must be completed to progress to the next one. Students are expected to make good progress; we have found students who fall behind often fail to successfully complete the class. In general, one or more modules are assigned each week. There are 2 weeks where no new module is assigned. This is a strong indication that the previous week’s module takes a lot of time (modules 7, 10 and 12). Modules will contain recorded videos, online tutorials, text and links to online resources. Each module will include a coding project or assignment, many of which will be graded automatically through Codio. You will be asked to pick a language by the end of the first week (Java or Python) at which point you will be invited to a language specific Canvas course. All content is accessed through this second Canvas course.

Grading

Each student starts with 0 points in the gradebook and works upward toward a final point total earned out of the possible number of points. In this course, each assignment constitutes a portion of the final grade, as detailed below: 70% - Codio Programming Projects 30% - Codio Tutorials and Canvas Quizzes 5% - Extra Credit: Bug Bounty

Letter grades will be assigned following the standard scale:

• 90% - 100% → A
• 80% - 89.99% → B
• 70% - 79.99% → C
• 60% - 69.99% → D
• 00% - 59.99% → F

Late Work

Since this course is entirely online, students may work at any time and at their own pace through the modules. However, to keep everyone on track, there will be approximately one module due each week. Each graded item in the module will have a specific due date specified. Any assignment submitted late will have that assignment’s grade reduced by 10% of the total possible points on that project for each day it is late. This penalty will be assessed automatically in the Canvas gradebook.

Even if a module is not submitted on time, it must still be completed before a student is allowed to begin the next module. So, students should take care not to get too far behind, as it may be very difficult to catch up.

Finally, all course work must be submitted on or before the last day of the semester in which the student is enrolled in the course in order for it to be graded on time.

If you have extenuating circumstances, please discuss them with the instructor as soon as they arise so other arrangements can be made. If you find that you are getting behind in the class, you are encouraged to speak to the instructor for options to make up missed work.

Incomplete Policy

Students should strive to complete this course in its entirety before the end of the semester in which they are enrolled. However, since retaking the course would be costly and repetitive for students, we would like to give students a chance to succeed with a little help rather than immediately fail students who are struggling.

If you are unable to complete the course in a timely manner, please contact the instructor to discuss an incomplete grade. Incomplete grades are given solely at the instructor’s discretion. See the official K-State Grading Policy for more information. In general, poor time management alone is not a sufficient reason for an incomplete grade.

Unless otherwise noted in writing on a signed Incomplete Agreement Form , the following stipulations apply to any incomplete grades given in Computational Core courses:

1. Students may receive at most two incompletes in Computational Core courses throughout their time in the program
2. Students will be given 6 calendar weeks from the end of the enrolled semester’s finals week to complete the course
3. Any modules in a future CC course which depend on incomplete work will not be accessible until the previous course is finished
4. For example, if a student is given an incomplete in CC 210, then all modules in CC 310 will be inaccessible until CC 210 is complete
5. Students understand that access to instructor and GTA assistance may be limited after the end of an academic semester due to holidays and other obligations
6. If a student fails to resolve an incomplete grade after 6 weeks, they will be assigned an ‘F’ in the course. In addition, they will be dropped from any other Computational Core courses which require the failed course as a prerequisite or corequisite.

Recommended Texts & Supplies

To participate in this course, students must have access to a modern web browser and broadband internet connection. All course materials will be provided via Canvas and Codio. Modules may also contain links to external resources for additional information, such as programming language documentation.

Subject to Change

The details in this syllabus are not set in stone. Due to the flexible nature of this class, adjustments may need to be made as the semester progresses, though they will be kept to a minimum. If any changes occur, the changes will be posted on the Canvas page for this course and emailed to all students.

Academic Honesty

Kansas State University has an Honor and Integrity System based on personal integrity, which is presumed to be sufficient assurance that, in academic matters, one’s work is performed honestly and without unauthorized assistance. Undergraduate and graduate students, by registration, acknowledge the jurisdiction of the Honor and Integrity System. The policies and procedures of the Honor and Integrity System apply to all full and part-time students enrolled in undergraduate and graduate courses on-campus, off-campus, and via distance learning. A component vital to the Honor and Integrity System is the inclusion of the Honor Pledge which applies to all assignments, examinations, or other course work undertaken by students. The Honor Pledge is implied, whether or not it is stated: “On my honor, as a student, I have neither given nor received unauthorized aid on this academic work.” A grade of XF can result from a breach of academic honesty. The F indicates failure in the course; the X indicates the reason is an Honor Pledge violation.

For this course, a violation of the Honor Pledge will result in sanctions such as a 0 on the assignment or an XF in the course, depending on severity. Actively seeking unauthorized aid, such as posting lab assignments on sites such as Chegg or StackOverflow, or asking another person to complete your work, even if unsuccessful, will result in an immediate XF in the course.

Use of AI text and code generators such as ChatGPT and GitHub Copilot in any submission for this course is strictly forbidden unless explicitly allowed by your instructor. Any unauthorized use of these tools is considered plagiarism.

We reserve the right to use various platforms that can perform automatic plagiarism detection by tracking changes made to files and comparing submitted projects against other students’ submissions and known solutions. That information may be used to determine if plagiarism has taken place.

Authorized Aid

All graded work is individual effort. You are authorized to use:

1.  course’s materials,
   

2.  direct web-links from this course
   

3.  the appropriate languages documentation (https://docs.python.org/3/  or https://docs.oracle.com/javase/ Links to an external site.)
   

4.  Email help received through  210 help email, CC - Instructors, GTAs
   

5.  Zoom/In-person help received from Instructors or GTA
   

6.  ACM help session (an on campus only resource) Most Tuesdays in EH 1116, 6:30PM. 
   

7.  Tutors from the Academic Assistance Center or provided by K-State Athletics 
   

Use of on-line solutions whether for reference or code is prohibited. Use of previous semester’s answers, whether your own or another student’s is prohibited. Use of code-completion/suggestion tool’s, other than those we have installed in the Codio editor, is prohibited.

Standard Syllabus Statements

Students with Disabilities

At K-State it is important that every student has access to course content and the means to demonstrate course mastery. Students with disabilities may benefit from services including accommodations provided by the Student Access Center. Disabilities can include physical, learning, executive functions, and mental health. You may register at the Student Access Center or to learn more contact:

• Manhattan/Olathe/Global Campus – Student Access Center
  • accesscenter@k-state.edu
  • 785-532-6441
• K-State Salina Campus – Julie Rowe; Student Success Coordinator
  • jarowe@k-state.edu
  • 785-820-7908

Students already registered with the Student Access Center please request your Letters of Accommodation early in the semester to provide adequate time to arrange your approved academic accommodations. Once SAC approves your Letter of Accommodation it will be e-mailed to you, and your instructor(s) for this course. Please follow up with your instructor to discuss how best to implement the approved accommodations.

Expectations for Conduct

All student activities in the University, including this course, are governed by the Student Judicial Conduct Code as outlined in the Student Governing Association By Laws , Article V, Section 3, number 2. Students who engage in behavior that disrupts the learning environment may be asked to leave the class.

Mutual Respect and Inclusion in K-State Teaching & Learning Spaces

At K-State, faculty and staff are committed to creating and maintaining an inclusive and supportive learning environment for students from diverse backgrounds and perspectives. K-State courses, labs, and other virtual and physical learning spaces promote equitable opportunity to learn, participate, contribute, and succeed, regardless of age, race, color, ethnicity, nationality, genetic information, ancestry, disability, socioeconomic status, military or veteran status, immigration status, Indigenous identity, gender identity, gender expression, sexuality, religion, culture, as well as other social identities.

Faculty and staff are committed to promoting equity and believe the success of an inclusive learning environment relies on the participation, support, and understanding of all students. Students are encouraged to share their views and lived experiences as they relate to the course or their course experience, while recognizing they are doing so in a learning environment in which all are expected to engage with respect to honor the rights, safety, and dignity of others in keeping with the K-State Principles of Community .

If you feel uncomfortable because of comments or behavior encountered in this class, you may bring it to the attention of your instructor, advisors, and/or mentors. If you have questions about how to proceed with a confidential process to resolve concerns, please contact the Student Ombudsperson Office . Violations of the student code of conduct can be reported using the Code of Conduct Reporting Form . You can also report discrimination, harassment or sexual harassment , if needed.

Netiquette

Online communication is inherently different than in-person communication. When speaking in person, many times we can take advantage of the context and body language of the person speaking to better understand what the speaker means, not just what is said. This information is not present when communicating online, so we must be much more careful about what we say and how we say it in order to get our meaning across.

Here are a few general rules to help us all communicate online in this course, especially while using tools such as Canvas or Discord:

• Use a clear and meaningful subject line to announce your topic. Subject lines such as “Question” or “Problem” are not helpful. Subjects such as “Logic Question in Project 5, Part 1 in Java” or “Unexpected Exception when Opening Text File in Python” give plenty of information about your topic.
• Use only one topic per message. If you have multiple topics, post multiple messages so each one can be discussed independently.
• Be thorough, concise, and to the point. Ideally, each message should be a page or less.
• Include exact error messages, code snippets, or screenshots, as well as any previous steps taken to fix the problem. It is much easier to solve a problem when the exact error message or screenshot is provided. If we know what you’ve tried so far, we can get to the root cause of the issue more quickly.
• Consider carefully what you write before you post it. Once a message is posted, it becomes part of the permanent record of the course and can easily be found by others.
• If you are lost, don’t know an answer, or don’t understand something, speak up! Email and Canvas both allow you to send a message privately to the instructors, so other students won’t see that you asked a question. Don’t be afraid to ask questions anytime, as you can choose to do so without any fear of being identified by your fellow students.
• Class discussions are confidential. Do not share information from the course with anyone outside of the course without explicit permission.
• Do not quote entire message chains; only include the relevant parts. When replying to a previous message, only quote the relevant lines in your response.
• Do not use all caps. It makes it look like you are shouting. Use appropriate text markup (bold, italics, etc.) to highlight a point if needed.
• No feigning surprise. If someone asks a question, saying things like “I can’t believe you don’t know that!” are not helpful, and only serve to make that person feel bad.
• No “well-actually’s.” If someone makes a statement that is not entirely correct, resist the urge to offer a “well, actually…” correction, especially if it is not relevant to the discussion. If you can help solve their problem, feel free to provide correct information, but don’t post a correction just for the sake of being correct.
• Do not correct someone’s grammar or spelling. Again, it is not helpful, and only serves to make that person feel bad. If there is a genuine mistake that may affect the meaning of the post, please contact the person privately or let the instructors know privately so it can be resolved.
• Avoid subtle -isms and microaggressions. Avoid comments that could make others feel uncomfortable based on their personal identity. See the syllabus section on Diversity and Inclusion above for more information on this topic. If a comment makes you uncomfortable, please contact the instructor.
• Avoid sarcasm, flaming, advertisements, lingo, trolling, doxxing, and other bad online habits. They have no place in an academic environment. Tasteful humor is fine, but sarcasm can be misunderstood.

As a participant in course discussions, you should also strive to honor the diversity of your classmates by adhering to the K-State Principles of Community .

Discrimination, Harassment, and Sexual Harassment

Kansas State University is committed to maintaining academic, housing, and work environments that are free of discrimination, harassment, and sexual harassment. Instructors support the University’s commitment by creating a safe learning environment during this course, free of conduct that would interfere with your academic opportunities. Instructors also have a duty to report any behavior they become aware of that potentially violates the University’s policy prohibiting discrimination, harassment, and sexual harassment, as outlined by PPM 3010 .

If a student is subjected to discrimination, harassment, or sexual harassment, they are encouraged to make a non-confidential report to the University’s Office for Institutional Equity (OIE) using the online reporting form . Incident disclosure is not required to receive resources at K-State. Reports that include domestic and dating violence, sexual assault, or stalking, should be considered for reporting by the complainant to the Kansas State University Police Department or the Riley County Police Department . Reports made to law enforcement are separate from reports made to OIE. A complainant can choose to report to one or both entities. Confidential support and advocacy can be found with the K-State Center for Advocacy, Response, and Education (CARE) . Confidential mental health services can be found with Lafene Counseling and Psychological Services (CAPS) . Academic support can be found with the Office of Student Life (OSL) . OSL is a non-confidential resource. OIE also provides a comprehensive list of resources on their website. If you have questions about non-confidential and confidential resources, please contact OIE at equity@ksu.edu or (785) 532–6220.

Academic Freedom Statement

Kansas State University is a community of students, faculty, and staff who work together to discover new knowledge, create new ideas, and share the results of their scholarly inquiry with the wider public. Although new ideas or research results may be controversial or challenge established views, the health and growth of any society requires frank intellectual exchange. Academic freedom protects this type of free exchange and is thus essential to any university’s mission.

Moreover, academic freedom supports collaborative work in the pursuit of truth and the dissemination of knowledge in an environment of inquiry, respectful debate, and professionalism. Academic freedom is not limited to the classroom or to scientific and scholarly research, but extends to the life of the university as well as to larger social and political questions. It is the right and responsibility of the university community to engage with such issues.

Campus Safety

Kansas State University is committed to providing a safe teaching and learning environment for student and faculty members. In order to enhance your safety in the unlikely case of a campus emergency make sure that you know where and how to quickly exit your classroom and how to follow any emergency directives. Current Campus Emergency Information is available at the University’s Advisory webpage.

Student Resources

K-State has many resources to help contribute to student success. These resources include accommodations for academics, paying for college, student life, health and safety, and others. Check out the Student Guide to Help and Resources: One Stop Shop for more information.

Student Academic Creations

Student academic creations are subject to Kansas State University and Kansas Board of Regents Intellectual Property Policies. For courses in which students will be creating intellectual property, the K-State policy can be found at University Handbook, Appendix R: Intellectual Property Policy and Institutional Procedures (part I.E.) . These policies address ownership and use of student academic creations.

Mental Health

Your mental health and good relationships are vital to your overall well-being. Symptoms of mental health issues may include excessive sadness or worry, thoughts of death or self-harm, inability to concentrate, lack of motivation, or substance abuse. Although problems can occur anytime for anyone, you should pay extra attention to your mental health if you are feeling academic or financial stress, discrimination, or have experienced a traumatic event, such as loss of a friend or family member, sexual assault or other physical or emotional abuse.

If you are struggling with these issues, do not wait to seek assistance.

• Kansas State University Counseling and Psychological Services offers free and confidential services to assist you to meet these challenges.
• Lafene Health Center has specialized nurse practitioners to assist with mental health.
• The Office of Student Life can direct you to additional resources.
• K-State Family Center offers individual, couple, and family counseling services on a sliding fee scale.
• Center for Advocacy, Response, and Education (CARE) provides free and confidential assistance for those in our K-State community who have been victimized by violence.

For Kansas State Salina Campus:

• Kansas State Salina Counseling Services offers free and confidential services to assist you to meet these challenges.
• The Kansas State Salina Office of Student Life can direct you to additional resources.
• The Kansas State Salina Campus offers several services for students, including health services, counseling, and academic assistance.

For Global Campus/K-State Online:

• K-State Online students have free access to mental health counseling with My SSP - 24/7 support via chat and phone.
• The Office of Student Life can direct you to additional resources.

University Excused Absences

K-State has a University Excused Absence policy (Section F62) . Class absence(s) will be handled between the instructor and the student unless there are other university offices involved. For university excused absences, instructors shall provide the student the opportunity to make up missed assignments, activities, and/or attendance specific points that contribute to the course grade, unless they decide to excuse those missed assignments from the student’s course grade. Please see the policy for a complete list of university excused absences and how to obtain one. Students are encouraged to contact their instructor regarding their absences.

Copyright Notice

© The materials in this online course fall under the protection of all intellectual property, copyright and trademark laws of the U.S. The digital materials included here come with the legal permissions and releases of the copyright holders. These course materials should be used for educational purposes only; the contents should not be distributed electronically or otherwise beyond the confines of this online course. The URLs listed here do not suggest endorsement of either the site owners or the contents found at the sites. Likewise, mentioned brands (products and services) do not suggest endorsement. Students own copyright to what they create.

Plagiarism Policy

Resources

• K-State Honor & Integrity System

Video Script

“On my honor, as a student, I have neither given nor received unauthorized aid on this academic work.” - K-State Honor Pledge

Plagiarism is a very serious concern in this course, and something that we do not take lightly. Computer programs and code are especially easy targets for plagiarism due to how easy it is to copy and manipulate code in such a way that it is unrecognizable as the original source but still performs correctly.

At its core, plagiarism is taking someone else’s work and passing it off as your own without giving appropriate credit to the original source. As a student at K-State, you are bound by the K-State Honor Code not to accept any unauthorized aid, and this includes plagiarized code.

When it comes to plagiarism in computer code, there is a fine line between using resources appropriately and copying code. In this program, you should strive to avoid plagiarism issues by doing the following:

1. Do not search for or use any complete solutions to projects in this course found online or from fellow students.
2. Small portions of code may be used or adapted from an online source with proper citation. To cite a piece of code, include a code comment section above it that contains the original source URL and a description of why it was used.

In general, copying or adapting small pieces of code to perform auxiliary functions in the assignment is permitted. Copying or adapting code that is the general goal of the assignment should be avoided. For example, if the assignment is to create a bubble sort algorithm, you should write the algorithm from scratch yourself since that is the goal of the assignment. If the assignment is to create a program for displaying data that you feel should be sorted, you may choose to adapt an existing sorting algorithm for your needs (or use one from a library).

If you aren’t sure about whether it is OK to use an online resource or piece of code in this course, please contact the instructors using the course discussion forums or help email address. You will not get in trouble for asking, and it will help you determine what the best course of action is. Plagiarism can really only occur when you submit the assignment for grading, so you are welcome to ask for clarification or a judgement on whether a particular usage is acceptable at any time before you submit the assignment.

Codio has features that will compare your submissions against those of your fellow students. Any submissions with a high degree of similarity may be subjected to additional scrutiny by the instructors to determine if plagiarism has occurred.

In this course, any violation of the K-State Honor Code will result in a 0 on that assignment and a report made to the K-State Honor Council. A second violation will result in an XF in this course, as well as any additional sanctions imposed by the K-State Honor Council.

For more information on the K-State Honor & Integrity system, please visit their website , which is linked in the resources section below this video.

Welcome to Codio

Welcome to Codio! For this class, we’ll be using Codio for most of our work. You will access Codio via the links provided in your class materials.

Each module will contain Codio tutorials, Codio projects and occasionally a quiz or discussion.

Click the Next button below, or the Right Arrow at the top of this page, to continue to the next guide page in this Codio project.

Codio Tutorials

Each module in Canvas will usually contain two Codio tutorial assignments. Some weeks may have more; in any event module content must be accomplished in order.

• The first tutorial is a programming language agnostic discussion of the concept the module introduces. Often this tutorial introduces pseudo code, has questions and may contain a Parsons Puzzle. Most of the questions only allow one attempt, however Parsons Puzzles will allow multiple tries.
• The second tutorial will contain your language specific implementation of this concept; the syntax (format) and semantics (behavior/meaning) of the specific keywords. This tutorial may include a programming example as well as a programming exercise.

In these Codio tutorials, there will be several pages of content introducing the material for that module. Some of the pages will look just like this one, with text, images, and maybe even a short video to help you learn the material.

If you’d like to see an outline of the pages available as part of this module, click the “hamburger” menu button at the top-right of the page.

Some of the pages may also include short questions to check for understanding of the material. You’ll need to answer these questions as they appear in order to get points for completing the tutorial module. Remember that the tutorials make up part of your grade in this course, so make sure you answer all of the questions in the tutorial module before submitting it. In some cases, you’ll be able to resubmit your answers until you get a correct answer, but other questions will not allow that.

In fact, below is a quick example of what one of those questions would be like. Take a moment to answer the question correctly, then continue to the next page of this module. For those of you unfamiliar with the work of Douglas Adams, the answer is forty-two.

Codio Examples

YouTube Video

On some pages, the Codio guide may also switch to a different view, shown here, allowing you to work directly with code. On the far left is the file tree, which shows all of the files accessible to you for this tutorial. Then, in the middle, you may also see one or more open files as tabs at the top of that panel. Those files are usually the ones that you need to edit to complete the example on this page. You can freely open additional files if needed in that panel, or rearrange the panels as needed. However, whenever you enter this page, it will reset the view back to the default.

In the first programming module of the course, we’ll discuss more information about how to use Codio to run any code that you’ve created. For now, we’ll just use text files to introduce the interface.

Once you’ve completed the example, most pages will include a section at the bottom that allows you to check your work. Just like the other questions, these assessments will count toward your grade on the tutorial project. See if you can complete the exercise and pass the test below. The answer is Picard.

Codio Interface

Now that you’ve seen a few pages in Codio, let’s take a minute to discuss some of the features of the Codio user interface. Of course, Codio has some amazing documentation , so feel free to check that out as you work with Codio.

First, let’s look at the menu items at the top of the page. There are several available to you that are worth mentioning. For starters, you can click the Codio Icon at any time to go directly to your Codio dashboard.

Under the Codio menu, you can also find options to manage your preferences. Here you can adjust things such as the editor settings and theme. Feel free to adjust the settings to match your personal preferences.

The Project menu allows you to work with the currently loaded Codio project. Generally you won’t need to access many of these items unless your project stops working. However, they are provided for your use in case you need them.

The File menu contains options for manipulating the file tree, such as creating new files, renaming them, saving them, and even downloading and uploading files. As you work on larger projects, you’ll be using many of these options to manage the files within your project.

Next, the Edit menu gives you access to the Undo and Redo action.

The Find menu contains entries for searching documents and performing a find-and-replace operation. Most of those actions should be pretty self-explanatory.

The View menu allows you to customize your view in Codio. Here we’ll find options for managing panels, open tabs, editor settings, and more. Feel free to make use of these options to arrange your Codio view as you prefer. Also, at the bottom of this menu is a Play Guide option, which is very helpful if you accidentally close the guide and need to reopen it.

Under the Tools menu, you’ll find an option for accessing the Terminal in your project. The Terminal gives you console access to the box that your project is running on.As you work through the content in this program, we’ll slowly introduce the Terminal and some of the tasks it can perform.

The Education menu is very important, though it only has a single entry. The Mark as Completed option allows you to indicate that you have completed this Codio project or tutorial. Once you select that option, your work will automatically be graded and your grade will be sent to Canvas. From there, you can access the next project or module in the course.

||| warning

Don’t Submit Projects Accidentally!

Be very careful when completing a project! Once you’ve marked a project as completed, it will become read-only, and you won’t be able to make any additional changes to the project. So, you’ll need to make sure you’ve finished everything in the project first. If you accidentally mark a project as completed, you may contact the instructors for help. Depending on the situation, they may be able to unlock it for you so you can continue your work. However, unlocking a completed project is entirely at the discretion of the instructor.

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Finally, the Help menu gives you access to many of the support features in Codio. If you get stuck, you may want to review some of the help options available here. Of course, you can always post a message in the course help forum or email for assistance! This is for help with Codio, not for help on the lesson content. In general your first request for help should be through the CC210-Help email.

There are also a few other items in the interface you should be aware of. First, in the File Tree, there is a Play icon that can also be used to open the guide for the current project.

In the guide, there are a couple of options available by clicking the gear icon in the upper-right of the page. First, there is an option to Restore Current Files. This option will restore the contents of any currently open files back to the default contents from when you first opened the project. In addition, this menu also contains another way to mark the current project as completed.

That covers most of the major features of the Codio interface that we’ll be using in this course. If you have any questions about how to use Codio, feel free to ask your teahers or email for assistance.

Important Notes

CC 210 Is 4 Credit Hours

The University guidance is you should spend 12 hours per week on a 4 credit hour course. We interpret this to mean twelve 50 minute sessions and assume you spend some time studying and reviewing class materials which is not captured in Codio. Historically, average students come close to this goal, with some weeks going over and the early weeks being low.

Caveats:

• We assume that when given two weeks for a project, the “effort” is split equally between both weeks.
• Students learn different concepts at different rates – your effort may vary

Substantially more effort is required to be successful in CC 210 than in CC 110.

Modules 1 - 5 Are Mostly Review

Non Python Students

If you are taking CC 210 in a language other than Python, Modules 1 - 5 will quickly introduce you to the basic control statements and variable types in your selected language. The concepts will be familiar but the application may be a bit more advanced than that which was covered in CC 110.

Python Students

If you are taking CC 210 in Python, Modules 1 - 5 may seem like total review. However, we introduce syntactical and semantic options that, for simplicity’s sake, were omitted from CC 110.

Do not become complacent based on the first 3 weeks of course work. This course will become more difficult quickly.

CC 210 Projects vs CC 110 Homeworks and Labs

CUT and PASTE in PROJECTS is Forbidden

We want you to use the Codio editor for your Projects. It is deliberately feature poor to emphasize the student’s knowledge of the language, not the editor’s fancy assistance. See your syllabus, but in general a project which has materials copied/pasted in may receive a 0.

Note: Although cut and paste are permitted in TUTORIALs, plagiarism is not. DO NOT paste in someone else’s work.

“Check-It” Buttons may not be Comprehensive

You must develop and test your projects from the terminal. In CC 110, the student assessment button ran the same test software that the grader did; thus your score on the “Check-it” button was a true indication of your Codio grade.

In CC 210, the “Check-it” button may be only a small subset the tests run for your Codio grade, so just because you pass those tests does not mean that your project is complete. This also does not guarantee you will receive a passing grade from the actual grader run after you submit your project. It is your job to test your code thoroughly in the terminal and develop your own test cases.

All Work is Subject to Manual review

Your submitted project may be reviewed manual for structure, forbidden commands, proper function from the terminal, etc. Please see your syllabus.

As a result your the score you receive from Codio may not reflect your final score. Here is the estimated points workflow:

1. The Autograder assigns a grade in Codio and LMS software (e.g. Canvas).
2. Manual review may deduct some points – see syllabus.
3. Plagiarism detection is run and penalties applied.
4. Late penalties may be applied.

Completing a Unit

That’s it! We’ve completed this unit in Codio, and we are now on the last page.

There’s just one more thing to do: we need to mark the unit as complete. When we do that, Codio will grade our work and then send the grade to Canvas. Once the grade is recorded in Canvas, we’ll get access to the next item in the module.

There are several ways to mark a unit as complete. First and foremost, the last page of the guide in each project should have a “Mark as Completed” button at the bottom of the page, but these textbook tutorials don’t. So, once we see that button, we’ll know we’ve reached the end of a project.

On the tutorials, we can click the gear icon in the upper-right of the page, and select “Mark as Completed” there. It should also be available in the tutorials as well.

Finally, we can find a “Mark as Completed” option on the Education menu at the top of the window. Each of these will perform the same function, so we can use any one of them when we are finished with our work.

The Codio Documentation gives several different ways that it can be done.

Of course, don’t forget the warning on the previous page - we should make sure we are completely done with the unit before marking it as complete.

So, let’s go ahead and mark this unit as complete by clicking the “Mark as Completed” option found by clicking the gear icon above, or the Education menu at the top. Once we do that, we’ll be able to complete the final few things in Canvas for this module, and then we can move on to Module 1 - Hello World!

What is Programming?

As with any learning adventure, we must begin somewhere. When learning how to write computer programs, one of the best questions to tackle first is “what is programming?” As it turns out, the answer to that question is key to understanding exactly what it is we are trying to learn.

A Simple Computer

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At its core, a computer is simply an electronic device that is capable of following instructions to perform calculations. In computer science theory, there is a special kind of theoretical computer called a Turing Machine that represents the simplest version of a modern computer. It might look something like this, as imagined by an artist:

¹

A Turing Machine consists of an infinitely long tape that can be used to store data, and a small control box that manipulates the tape. The control box knows how to perform a few simple instructions, such as “Move Left” or “Write 0.” So, to program a Turing Machine, we must simply tell the control box which instructions to follow, and it can do it. For example, if we want the Turing Machine to write “101” on the tape, we could write the following program:

1. Write 1
2. Move Right
3. Write 0
4. Move Right
5. Write 1
6. Stop

Seems simple enough. We won’t go into the details here, but computer scientists have been able to prove that any computer program that can run on a real computer could also be performed on a Turing Machine, as long as the Turing Machine has infinite time and an infinitely long tape.

This video shows an example of what a Turing Machine might look like in real life.

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So, all we really need to learn is how to write programs for a Turing Machine, right?

A Modern Computer

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Well, it’s unfortunately not that simple. There are two major differences between a Turing Machine and a modern computer that we must deal with. First, a modern computer knows many more instructions than a Turing Machine. To learn how to write programs that a modern computer can understand, we’d have to learn an entirely different vocabulary of commands. At the same time, modern computers are very complex systems, so any program we write might not be very efficient at doing what we want.

So, to learn how to write computer programs quickly and easily, we really want to be able to do two things:

1. Use a vocabulary of commands that are familiar to us
2. Have those commands turn into programs that run efficiently on a modern computer

Compilers & Interpreters to the Rescue!

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Developing computer programs was very difficult work in the 1950s, and many of those early programmers were looking for a better way to solve that exact problem. One of these was Rear Admiral Grace Hopper, shown above. Her team was one of the first to develop the idea of writing computer programs using English words, and then using a second program, which they called a compiler, to convert those English words into instructions a computer could understand.

Their compiler made developing computer programs much simpler, since programmers didn’t have to learn an entirely new vocabulary to tell the computer what to do. Instead programmers simply had to learn the rules of what a computer could and couldn’t understand, and the syntax, or grammar rules, of how the compiler expected the program to be written. These new programming languages that use English words are referred to as high-level languages.

Programmers would now write the source code for the program in a high-level language, and then use a compiler to generate the machine code that the computer would actually run. In addition, since the compiler was a program itself, it could make sure the machine code it generated was as fast and efficient as possible, eliminating lots of hard work programmers would have to perform to tailor each program to fit the hardware it was going to run on.

Today, programming languages such as C, C++, and Java use compilers to convert source code into machine code.

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At the same time, other developers such as Steve Russell, shown above, were working on another type of program, called an interpreter, to solve the same problem. An interpreter can read source code and immediately tell the computer what steps to perform, without needing to generate the whole machine code first. This makes it much easier to write and edit programs on the fly, as the interpreter reads the source code directly each time the program runs. Today, programming languages such as PHP, JavaScript, and Python use interpreters to run the source code on a computer.

Programming

So, programming is simply the act of writing computer code in a way that a computer can run it. In most cases today, that means developing the source code for a program in a high-level language, then using either a compiler to generate the machine code for that program, or an interpreter to run the program directly on the computer from the source code. Of course, we can always write machine code by hand, but that is quite a bit more difficult.

In this class, we’ll learn how to write source code in one of two common languages, Java and Python. They both have their own unique features, especially since Java is a compiled language and Python is an interpreted language. However, as we saw above with the Turing Machine example, each language can be used to write any computer program. So, the choice of language is really more about personal preference and the unique features of each language than anything else.

This makes sense, because in general we can use both English and Spanish, as well as most other languages today, to express the same thoughts and ideas, even if we may not always have a word with the same meaning in both languages.

Running a Program

Modern computers share many theoretical similarities with the Turing Machine, but in practice they are much more advanced. In this section, we’ll discuss how a modern computer is able to run programs we’ve written in a high-level programming language like Java or Python.

Learning to program requires some basic understanding of how a computer works. In the most basic sense, a computer has a large amount of memory connected to a central processing unit (CPU). The memory consists of many bytes of data, each containing eight binary values (e.g. 01001101).

The memory itself is split into various regions, with different regions storing the machine code instructions that make up a program and the data that the program is operating on.

The CPU contains enough circuitry to interpret the instructions it is given and perform the requested mathematical and logical operations on the data provided.

Consider a single line of code in a program:

z = 5 + 7

In most languages, a line similar to this will instruct the computer add the values of 5 and 7 and save the value into a variable named z, which will be stored in some location in memory. In a machine language, this single line of code may be actually require different instructions to complete. The table below shows one possible interpretation of that line of code into machine language.

Machine language is pretty ugly, but this is really how a CPU functions. Thankfully, we have many higher-level programming languages available, such as Java and Python, so we usually don’t have to write code directly in machine language.

Estimating Program State

From this, we can come up with a pretty powerful abstraction that represents how a computer works. In programming, an abstraction is a simplified model of a complex system, keeping only the most important details to make using the model easy.

In our abstract model of a computer, we see that a program consists of an ordered list of instructions to be executed, and memory is a set of labelled boxes that can store any data our program requires. We also have a pointer that keeps track of which instruction the computer is currently executing. The list of instructions, the instruction pointer, and the memory combined all make up a program’s state when it is running on a computer. Tools such as Python Tutor or Java Tutor use a model very similar to this to help us understand how our programs actually work.

The Software Development Lifecycle

Another big idea in computer programming is the software development lifecycle. There are many different ways to approach developing a large computer program, but most of them can be divided into a few clear steps, as shown in this diagram.

Requirements

The first step is the requirements analysis phase. In this phase, a software developer works to clearly describe and understand the problem to solve and the features that the solution should have. Throughout this course, the problem statement or programming project description will form the requirements for the program to be written.

Design

Next comes the design phase. In this phase, we describe the solution in terms of the actual structure of the code. In Object-oriented programming, this generally consist of designing the classes and the interactions between them which meet the requirements.

A class is a collection of data and the methods (procedures) by which data is accessed and manipulated. Classes are generally organized around things (the shopping cart from any online store is a classic example) or functions (communication with your computer’s network card is probably handled by a class). Similar to the requirements, the design of most of the projects in this course will be provided, but it is important to pay attention to those designs since later courses may leave the design up to the developer.

Code

Following the design phase is the development, or coding, phase. In this phase, actual code is written to match the requirements and design from the previous phases.

This course primarily focuses on this phase of the software development lifecycle. In this course, we’ll cover how to write code in classes and methods to perform various operations on data. We’ll also learn how to store and manipulate data in variables and data structures.

Testing During Development

Testing while coding is an important part of the coding process. Good programmers constantly test small parts of their code, both by running the code and by continually thinking about the code, any time they complete a task. When a program fails to run correctly, we say that it contains a “bug” and the process of finding and fixing those bugs is known as “debugging.”

There are many advantages to testing while coding:

1. This allows the developer to develop their own test cases and have a better understanding of what the code is supposed to do and where any problems may be.
2. Any bugs introduced or revealed by the most recent addition of code become much easer to find.

We recommend a “code a little, test a little” approach in this class. This helps us narrow down which parts of the code are working properly and which ones contain bugs to be removed. If we write too much code without testing any of it, it can be very difficult to isolate and fix the bugs.

Test

When the development phase is complete, we move on to the formal testing phase of development. In this phase, the software is formally tested to ensure that is matches the specifications and design, usually by specially trained test engineers who can report any bugs that are found back to the developers.

In this class, the autograder that we use serves as a formal test process. It isn’t perfect and won’t catch every bug, but it does a good job of helping you determine if your program meets the specifications for the project.

Deploy

Finally, there is the deployment phase. This is where the code is packaged and released to the users. In this course, this is analogous to turning in our project and marking it complete. At this point, it is very difficult to fix any bugs without making a new release of the software.

OOP Features

In this course, we will be teaching programming from the object-oriented perspective. Both Java and Python support this programming paradigm, and it is commonly used in industry today. However, it is easier to understand some of these concepts (such as classes and objects), after first covering some of the fundamental concepts.

Thus, the first few modules of this course will contains some pieces of starter code that we’ll use without really explaining much about how they work, but rest assured that we’ll cover those concepts at the correct time in the course. Likewise, many of the early programming assignments will include some frozen starter code that provides the structure, and the point of the assignment will be simply to fill in the middle portion of the program that contains the actual code.

Before we begin programming, let’s go over some basic terminology and rules for high-level programming languages.

Syntax

First, all high programming languages have a syntax, which is a pattern of words and symbols that all correct instructions in the language much follow. So, when we receive a syntax error from the compiler or interpreter, we should know that one or more lines of code in our program doesn’t follow the rules of the language. In a very real sense, this is the grammar that all correct programming lines will follow.

Natural languages also have a grammar, but most natural language listeners can understand improper grammar. The question “Which room is the dog in?” which contains the dreaded dangling preposition, will almost certainly be correctly interpreted as “in which room is the dog?” by most listeners.

Programming languages are not like this – the slightest violation of a grammar rule will result in code that most likely will not run. So, as developers we must learn to be very precise and exact in our code. This is a difficult skill to learn, but we’ll develop it over time with practice.

Semantic

Second, all programming instructions have a specific meaning, known as the semantics of the language. When one of our programs compiles and executes but produces an incorrect result, this is due to a semantic error (sometimes known as a logic error) in our code.

Unfortunately, the compiler or interpreter isn’t able to help us find any semantic errors, but we can find them through careful testing of our code.

Initial Vocabulary

Finally, all programming languages have various defined structures, which we can think of as the “parts of speech” in the programming language. This is similar to the concept of nouns, verbs, and adjectives in the English language.

This is a list of some of the most common parts in a programming language:

• keywords - a word that has a special meaning. These words tell the program exactly what to do, and we cannot use these words as identifiers. For example, in both Java and Python the word class is a keyword. We cannot use a keyword for any purpose other than the one(s) intended by the programming language.
• literal – text evaluated as itself, for example numbers (such as 6.626) are meant to represent themselves. Similarly, text literals are most often enclosed in double quotation marks (such as "wildcat"). Text literals are most commonly referred to as strings.
• identifiers - any class, method, or variable name is considered an identifier. Each language will have both rules (syntax) about what can be identifiers and conventions (style guides) about how to construct them.
• variable – a programmer-defined piece of data. Programmers name their variables with an identifier.
• method - a piece of code that performs an action in our program. Methods are sometimes referred to as functions or subroutines as well, but we’ll use the term method. Programmers name their methods with an identifier.
• class – a collection of variables and the methods used to manipulate that data. Classes lay at the heart of object-oriented programming and will be the focus of the last third of this course.
• symbols - any non-alphanumeric character which has special meaning. Common ones include the math symbols (+ - / * =), brackets of all forms (() [] {}), and then some not so obvious ones ( . , ; " !).

Program Structure

When writing code in an object-oriented language, many times we must use some additional syntax and structures in our programs that are required by the language, even though they aren’t strictly required for the program we are trying to develop.

In this section, we’ll briefly discuss some of those limitations. Later on in this course, we’ll come back to these concepts and explain them more fully, but for now we’ll provide some of this structure as starter code for the first few modules.

Everything Is In a Class

Classes are the blueprints of objects. In an object-oriented program, everything is inside a class definition. In this class, every file will contain exactly class definition or class-body.

// Java
public class ClassName {
    class-body
}

# Python
class ClassName:
    class-body

Code Block Delimiters

The class-definition is a “code-block.” Code-blocks signal a boundary to the compiler. This helps the compiler manage identifier names, memory and other things.

Code-blocks are delimited, or set apart, by various symbols. In Java, this is done with brackets { code block }. Spacing is often also used to make the code more readable, so that everything in a block lines up.

In Python, each code block is indented to the right. In this class we will use 4 spaces. When a line ends with a colon, Python expects the next line to be the start of a new code block (and therefore indented).

public class Foo{
    statement one
    statement two
}

public class Bar{
    statement_three
}

class Foo:
    statement_one
    statement_two

class Bar:
    statement_three

In the preceding examples, statement_one and statement_two are the code block for the class named Foo, and statement_three is part of the code block for the class named Bar.

Every Program Starts Somewhere

By tradition (and by rule in many languages), object-oriented programs start in a method called main().

// Java
public class ClassName {
    public static void main(String[] args){
        // method-body
    }
}

# Python
class ClassName:

    @classmethod
    def main(args):
        # method-body

For the first several modules, all of the code we need to write will be in the method body for the main() method. This area will be clearly marked in the starter code using a comment similar to WRITE YOUR CODE HERE.

Hello World

Tradition dictates that the first program in any introduction course is Hello World. Hello World simply prints the text “Hello World” to the screen.

Below is an example of an object-oriented version of this program in both Java and Python:

// Java
public class HelloWorld{
    public static void main(String[] args){
        System.out.println("Hello World");
    }
}

# Python
class HelloWorld:
    @classmethod
    def main():
        print("Hello World")


HelloWorld.main()

In each program, the actual work is done by the line containing the word print. In the rest of this module, we’ll explain the details behind the structure of this program.

Summary

We’ve now written our first program in a real, high-level programming language. While the program may only consist of a few lines of code at most, it is still a very big step toward writing bigger and more advanced programs.

Computer technology has some quite a long way since the 1950s, but the same needs that drove the development of compilers and interpreters continue today to drive the development of more advanced programming languages and related tools. It’s a very exciting field to experience firsthand, and once we understand a bit of code, we’ll be able to see it for ourselves.

In the next chapter, we’ll dive in head first to learn all about how to store and manipulate various types of data in our programs.

The World as Data

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Everything in the world can be represented using data. Think about that for a minute. Does it make sense?

Picture a tree. That tree can be described by its width, height, age, number of leaves, and even its color or texture. What about a person? A person has a name, age, height, and many other attributes. Could we simply represent trees, humans, and other entities in our computer programs using their attributes?

That’s the next big step in learning how to write a computer program: dealing with data. Many of the programs we’ll write are simply built to help us manipulate data in some fashion. Think back to the Turing Machine example from the first chapter. All a Turing Machine does is manipulate data on a tape, and it is capable of running any possible computer program.

In this chapter, we’ll learn all about the different ways we can work with data in our programs.

Variables

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First, let’s talk about variables. A variable is a placeholder for another value in a computer program. Most students first learn about variables in a mathematics course, such as Algebra. For example, in math, we might see the equation $ x + 5 = 10 $, where $ x $ is a variable, or placeholder, for a value. Using the algebraic rules, we can solve that equation to find that $ x = 5 $.

Variables in a computer program share some similarities with variables in math, but have some differences as well. First, variables in a computer program are also placeholders that represent a value. However, in programming, instead of representing an unknown value, variables in a computer program represent a stored value, one which we can always access.

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One way to think about variables in a computer program is to imagine them as a cardboard box. When we declare a variable, we are making a new box and giving it a name, which is the identifier of the variable. In the picture above, we’ve declared a variable named height.

Then, we can store a value in that variable, using a statement such as height = 42, which will put the number 42 inside of the height variable. This is an assignment statement, which we’ll cover in detail in this chapter.

Later in our program, we can then access the value stored in that variable and use it for calculations or output. For example, if we have additional variables named width and area, and have already stored the value 10 in width using width = 10, we can calculate the area of rectangular object using a statement such as area = width * height. This would use the current values in the height and width variables, and then store the result in the variable named area.

Behind the scenes, each time we declare a variable, we are telling the computer to set aside a small piece of memory in which to store something. We give the variable a name when we declare it, and then we can use that name to store or retrieve data from the location in memory our computer gave us.

Using variables effectively is a essential to writing good computer programs. This chapter will introduce many of the concepts related to dealing with variables and data in our code.

Basic Data Types

In a computer, all data, even the instructions, is stored in a binary format. Binary data consist entirely of 1s and 0s, or, in the case of a computer, it could be represented as “on” and “off” for current in a circuit, or “positive” and “negative” charges stored on a magnetic storage device. It could even be “open” and “closed” for physical memory gates. There are many different ways to represent it, but it all boils down to just 1s and 0s.

Of course, we need a way to convert between the binary 1s and 0s that a computer understands and the actual data we’d like to represent. On this page, we’ll cover some of the common types of data and how they are handled by most computer programming languages.

Common Numerical data

Numbers, and thus numerical literals, are used everywhere in computer programs. This goes beyond obvious arithmetic and accounting applications. Modern graphics, artificial intelligence and simulation programs use numerical representations of data to quickly perform their operations. Thus, it is unsurprising that there are many ways to write and store numeric data.

Integers

The first type of data we’ll deal with in our computer program is whole numbers. These are numbers such as 1, 0, -1, 25, -186, 12852, and more. In both mathematics and programming, we refer to these numbers as integers. An integer is any whole number, or a real number without a fraction or decimal component. We sometimes refer to these numbers as counting numbers.

To store these numbers in our computer program, we typically use a signed integer data type. This data type allows us to store both positive and negative numbers in binary in our computer’s memory. We won’t go too far into the details of how that works in this course, but there is more information on how that works on Wikipedia

Floating Point

Next, we’ll also need to handle numbers that include a fraction or decimal component. These include rational numbers such as 1.5, -2.98, 3 1/3, and even irrational numbers such as $ e $ and $ \pi $.

Our computer uses a special representation known as floating point to store these numbers. Floating point is very similar to scientific notation, where a number such as 1,230,000 is represented as $ 1.23 * 10^{6} $. In this example, 1.23 is the significand and 6 is the exponent of the number. It is known as floating point because the decimal point “floats around” the number based on the exponent. We could represent the same number as $ 12.3 * 10^{5} $ or $ 0.123 * 10^{7} $ just by adjusting the exponent, causing the decimal point to move within the significand.

Modern computers use the IEEE 754 standard for encoding floating-point numbers into binary. Again, we won’t go into the specifics here, but the graphic below gives us a good idea of how a floating point number can be broken up and stored in binary.

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Here we can see that a 64 bit space in memory is divided into three parts, one for the sign (to denote either a positive or negative number), another for the exponent, and a third for the fraction or significand of the number.

Boolean

Boolean values, named for George Boole represent true and false in a computer program. While it may be as simple as storing a single bit, with 0 and 1 representing true and false, most programming languages provide a special way to deal with these values as they are very important in our computer programs. We’ll spend most of the next several chapters discussing how to work with Boolean values, but for now they are just another type of data our program could store.

Text as Data

Character

Many high-level programming languages have a character data type. A character represents a single letter in a written language such as English. Most programming languages use a special code called ASCII , or the American Standard Code for Information Interchange. It defines a numerical value for each character in the English language, as well as several special characters such as the newline or \n character we’ve already seen. Below is a table showing the entire ASCII code.

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So, to store the character c, our computer would store the number 99 in binary. We should also notice that the capital and lowercase letters are separate, so C is 67.

Modern computer programming languages also support the use of Unicode characters. We won’t cover that in this course, but it is important to remember later on when working with languages other than English.

String

Sometimes we want to store entire sentences in our computer programs. A sentence is just a String of characters, object-oriented languages use a string class for this purpose and we’ll cover everything we need to know about strings in a later chapter.

Data Types in Detail

A variable in a high level language is just a memory address. It tells the compiler/interpreter where to start looking for the binary string of data.

Decoding the binary

All high-level programming languages use a type system to tell the system how to decode the binary data it finds there. All types have a size and a semantic which describes how many bits are in the data and how to interpret each bit. Consider the 2-byte (16-bit) binary sequence 1100 0110 1110 0100, it can be interpreted as many values based on its type.

Performing Operations

Operations and methods are only defined for specific types. For example, we can divide two integers, but not two characters. Likewise, integer division works differently than floating point division, which we’ll cover later in this chapter. It is up to the programmer to select the appropriate type for a variable and keep track of it.

Implications for Object-Oriented Programming (OOP)

All objects are created from a class definition. For example, an object created from a class named Cat is itself a new data type. A key part of object-oriented programming is that objects modify their own data. So, understanding the type of each variable is vital to understanding program state, which allows us to verify correct behavior and troubleshoot buggy code.

Typing Systems

Static (i.e. Java)

One typing system, often used by compiled languages, is the static type system. In this scheme the programmer explicitly tells the compiler the type of each variable when the is declared or defined. The statement int x = 5; tells the compiler that:

1. it should reserve a memory address for an integer variable
2. that the programmer is going to use the variable name x for that memory address
3. it should always interpret the bits stored in x as an integer
4. it should put the binary string which, when evaluated as an int is equal to the decimal number 5 into the reserved memory address

Dynamic (i.e. Python)

Another typing system, often used by interpreted languages, is the dynamic type system. In this system, the interpreter infers (guesses) the type of the variable based on the literal or variable in the definition. The statement x = 5 tells the interpreter:

1. to infer a type based on the literal 5
2. to reserve a memory address for the inferred type
3. that the programmer is going to use the variable name x for that memory address
4. to put the binary string which, when evaluated as the inferred type is equal to the decimal number 5 into the reserved memory address

Converting Between Types

High-level languages typically have operations or methods to convert from one data type to another.

For example, in Java, to print a line to the terminal, we use the System.out.println() method. As input, this method expects to receive a value that is a String data type. So, many languages include methods such as the toString() method built into all Java classes, as well as the str() method provided by Python, to convert most data types into a string. When a programmer explicitly tells the computer to convert one variable Type to another, the process is called casting.

Thankfully, many languages also allow some data conversions to happen automatically through a process known as coercion. In most modern high-level languages, when a method is supplied the wrong type of parameter, the language checks to see if there is an automatic conversion from the supplied type to the required type. If so, the language first converts the incorrect parameter to the correct type, then calls the method. The same procedure is used for operators. Depending on coercion for simple types is a common practice. Depending on it for more complex types or programmer developed classes can be more difficult and result in errors.

In practice, we generally should prefer explicitly casting variables to convert their types instead of relying on coercion. Casting ensures the program does exactly what we expect it to do.

Arithmetic

Once we have data stored in our programs, there are a number of ways we can manipulate that data. Let’s look at a few of them here.

Basic Operations

At its core, a computer is capable of performing all of the basic arithmetic operations, so we can write programs that can add, subtract, multiply and divide numbers. However, there is one big caveat that must be dealt with.

As discussed on the previous page, computer programs can store numbers as both integers and floating point numbers. What happens when we perform operations on two different types of numbers? For example, if an integer is added to a floating point number, would the resulting number be an integer or a floating point number, as in $ 1 + 1.5 $?

As our intuition suggests, performing the operation gives us $ 1 + 1.5 = 2.5 $, which is a floating point number. In general, when performing an operation on either two integers or two floating point numbers, the result will match the type of the two operands. However, when performing an operation on both an integer and a floating point number, the result is a floating point number.

There are two notable exceptions to this rule:

1. In a strongly-typed programming language, such as Java, the result may be converted to match the type of the variable it is being stored in, if allowed by the language.
2. When dividing two integers, the result may be either a floating point number or an integer, depending on the language.

We’ll discuss both of these exceptions later in this chapter when we dig into the details for each programming language.

New Operations

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In addition to the basic operations listed above that we are all familiar with from our mathematics class, there are a few new operations we should be aware of as well.

Modulo

The first new operation, the modulo operation, finds the remainder after dividing two numbers. It is typically written as $ 9 \bmod 5 $ when printed, but most programming languages use the percent sign %, as in 9 % 5 to refer to this operation.

To calculate the result of the modulo operation, we must look back to long division. In the example above, we can calculate $ 9 \bmod 5 $ by first calculating $ 9 / 5 $, which is $ 1 $ with a remainder of $ 4 $. So, the result of $ 9 \bmod 5 $ is $ 4 $.

Another way to think about the modulo operation is to simply find the largest multiple of the second operand that is smaller than the first, and then subtract the two, just like you do when performing long division. So, we can find $ 42 \bmod 13 $ by first calculating the largest multiple of $ 13 $ that is smaller than $ 42 $, which is $ 39 $, or $ 13 * 3 $. Then, we can subtract $ 42 - 39 = 3 $, so $ 42 \bmod 13 = 3 $.

The modulo operation is very important in many areas of programming. In fact, it is one of the core operations for most modern forms of encryption!

Truncated & Floor Division

As discussed a bit earlier, one of the stranger things in programming is dealing with division. When dividing two integers, it is possible to end up with a result that is a floating point number, as in $ 9 / 8 = 1.125 $. So, how should we handle this?

It turns out that each programming language may handle it a bit differently. For example, Java would truncate the result by removing everything after the decimal point to make the result an integer. So, in Java, the statements 99 / 100 and -99 / 100 would both usually evaluate to 0. However, we can force the result to be a floating point number by making sure that at least one of the operands is a floating point number, as well as the variable we are storing the result in.

Python, on the other hand, would store the result as a floating point number by default if needed. However, Python also includes a special operator, known as floor division or //, that would round the result down. For positive numbers, this means that the result would be rounded toward 0, while negative numbers would be rounded away from 0. So, in Python, the statement 99 // 100 would evaluate to 0 since it is rounded toward 0, while -99 // 100 would evaluate to -1 since it is rounded away from 0.

In short, we just need to pay special attention when we use the division operation to make sure we get the result we expect.

Assignment & Equality

Lastly, we should briefly discuss the assignment operator. We’ve already come across it earlier in this chapter. In mathematics, we usually use the equals sign = to denote equality, as in $ x + 5 = 10 $.

In programming, we use the single equals sign = to perform assignment. This allows us to store a value into a variable, as in x = 5. This would store the value $ 5 $ into the variable x. We could also say that we assign the value $ 5 $ to x.

However, it is very important to note that the variable we are assigning a value to goes first, on the left side of the equals sign. So, we cannot say 5 = x in most programming languages.

More on Operations

Operation

Computer Science, and therefore programming, has its roots in mathematics and uses a lot technical terms and jargon from math. Unfortunately this means that most programmers need to be familiar with some of this jargon.

An operation is a fancy math term for “do something”, but carries with it its own set of vocabulary. An operation is composed of:

1. an operator (one or more symbols)
2. operands (one or more pieces of data)
3. a semantic meaning (i.e. what the operator does)

Binary Operations

Binary operations operate on two inputs. This class of operations should be familiar from arithmetic. Its format is

    operand1 operator operand2
        2     +        4
        x     +        y

where the operator is typically some type of symbol.

Operator symbols are typically overloaded in programming languages, which means that they can do different things based on the types of the operands. For example, a typical language might do any of the following operations when the plus sign + is used as the operator, depending on the types of the individual operands:

We will have to refer to our language’s documentation for how each operator functions. Operator behavior, particularly in the presence of mixed-type operands varies from language to language.

Unary Operations

There are some operations that have just one operand, these are called unary operations. The typical form is operator operand or operand operator. A fairly common unary operator is ! for the logical operation “not”. !True is the same as False. We’ll introduce more of these operators in a later chapter.

User Input

Most programs process some type of user input, either text input by the user, mouse clicks on the screen, or many other methods. In this course, we’ll typically deal with three different types of user inputs:

1. Command-line arguments
2. Reading from a file stream
3. Reading from the keyboard stream

For the first few chapters, we’ll go ahead and provide the code needed to handle and process user inputs. As we learn more, we’ll go deeper into detail about each method and discuss the nuances involved with reading and processing user input.

 int x = 3
 int y = 4
 int z = x + y
 print (z)

Command Line Arguments

Command-line arguments are pieces of data that are provided to the program when executed as part of the initial command. For example, we learned that we can run a basic Hello World program using a command similar to these:

# Java
java HelloWorld

# Python
python3 HelloWorld

We can provide a command-line argument to these programs by including them after the command. For example, we could re-write our program to make user of the user’s name when provided as the first command-line argument. In that case, we can use the following command to run our program:

# Java
java HelloWorld Willie

# Python
python3 HelloWorld Willie

In this example, Willie is the input provided as the first command-line argument. We can change that to be any value we want.

Common Properties of Command Line Arguments

There are some common properties of command line arguments we should be aware of

1. Arguments are passed in as strings. Programmers must convert them to the appropriate data types.
2. Arguments are passed in order from left to right. If a problem specification asks for a positive number then a negative number, we must provide them in that order.
3. Arguments are separated by one or more spaces.
4. There are ways for a program to tell how many arguments there are.

That’s pretty much it. User input can be provided on the command line in the form of string arguments (values). When the command is run, these arguments are packed up by the operating system and given to the program. When command line arguments are required (or optional), the problem statement will tell us their order and purpose. The decision on whether or not to use command line arguments is typically a design consideration.

Streams

Both file and keyboard input are handled as streams. Streams are a computer science abstraction for data that is organized in a queue. Data (usually bytes) are ordered and read from front to back. We can see how this works for the keyboard. When we type “dog” the keyboard stream (called stdin for “standard input”) receives the bytes [100, 111, 103]. Files from a disk drive are similarly read first byte to last.

Streams as Objects

Object oriented high level programming like Java and Python have built in classes that read values from a stream. Thus, with some minor set up differences, the commands to read from a file are typically exactly same as the commands to read from the keyboard. This is the power of abstraction – the details of how to read from these different streams are hidden from the programmer who only wants read them.

Streams are literally bytes of data. We will use methods that interpret those byes as text, and then convert the text to the type of variable we need.

We’ll learn more about reading data from the keyboard and from a file later in this course.

Summary

We’ve now learned a lot about variables and data types in our programming language. We can use this information to build programs that store and manipulate large amounts of information.

We still have quite a bit to learn before we have the basics of programming covered. As we continue, we’ll see the usefulness of variables and the various data types we’ve learned.

The Laws of Thought

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In this chapter, we’re going to step away from computer programming for a bit to discuss a more foundational topic: logic. Logic and reasoning are core concepts at the heart of any level of education, and they are one of the major ways we are able to understand the world around us. Without logic and reasoning, we cannot build upon information we learn to create deeper meaning. Instead, all we are left with are facts, without any knowledge or wisdom gained from them.

Aristotelian Logic

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The earliest approach to formal logic comes from the work of Aristotle, seen above. His work established rules by which further information could be inferred, or deduced, from a set of truths about the world known as premises.

For example, in Aristotelian logic, we might find the following premises to be true:

Socrates is a man All men are mortal

Using Aristotle’s rules for logic, we can infer from those premises the following conclusion:

Socrates is mortal

This becomes a powerful system for inferring additional information based on facts in the world. By supporting each conclusion with premises and rules, it is possible to build a great wealth of knowledge.

Boolean Logic

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In the 1800s, there was a great interest in using the rules of mathematics to understand the world as well. Mathematics contains a well understood set of rules and operations, and many thinkers hoped to find a way to apply those rules in the world of logic as well. By doing so, they could move away from using an imprecise spoken language to reason about the world, and instead use the very precise language of mathematics.

In 1854, George Boole, seen above, published An Investigation of the Laws of Thought on Which are Founded the Mathematical Theories of Logic and Probabilities , a book which described exactly how to combine mathematics and logic into a single system. Using the system he proposed, it became very easy to use mathematical expressions and rules to perform the same logical inferences that Aristotle first used nearly 2000 years prior.

In Boolean logic, we may understand the following premises to be true:

$$ A \land B $$ $$ B \land C $$

In this instance, the $ \land $ symbol is used to denote the word “and”. We’ll learn more about these symbols later in this chapter. Using a rule from Boolean logic, we can reach the following conclusion:

If we compare the example from Aristotelian logic above to this example from Boolean logic, we can quickly see that they are very similar in structure. The first premise establishes a relationship between two items. The second premise establishes another relationship between the second item in the first premise, and a third item. The conclusion states that there must be a relationship between the first and third items. This is very similar to the transitive property of some mathematical operators.³

In programming, we use Boolean logic to control many aspects of how our computer programs function. In this chapter, we’ll learn all about how Boolean logic works so we can apply it correctly in our programs.

Logic Operators

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Boolean logic contains four operators that perform various actions in a Boolean logic statement. Before we learn about them, let’s take a minute to discuss variables in Boolean logic.

As we covered in a previous chapter, most programming languages support a special data type for storing Boolean values. That data type can only contain one of two values, True or False. So, in a Boolean logic statement, any variable can only be either True or False

For each of the operators below, we’ll see both a truth table and Venn diagram representation of the operation. They both present the same information, but in a slightly different way. In each operation, we’ll see all possible values of the variables present in the statement, and the resulting value of the operation on those variables. Since each variable can only have two values, the possibilities are limited enough that we can show all of them.

In the Venn diagrams below, each circle represents a variable.¹ The variables are labeled in the circles on each diagram.

Not $ \neg $

The first, and simplest, Boolean logic operator is the not, or negation, operator. This operator simply negates the given Boolean value, turning True into False and False into True. When written, we use the $ \neg $ symbol, but most programming languages use an exclamation point ! instead.

Below is a truth table giving the value of $ \neg A $ and $ \neg B $, for all possible values of $ A $ and $ B $.

We can also see the operation visually using a Venn diagram. In these drawings, assume each individual variable is True, and the shaded portion shows which parts of the diagram are True for the entire statement.

$ \neg A $

As we can see, if $ A $ is true, then $ \neg A $ represents everything in the diagram outside of the circle labeled $ A $. In fact, it includes the area outside of any circle, which represents the whole universe of items that are neither inside of $ A $ nor $ B $. So, the value of $ \neg A $ is not affected by the value of $ B $ in this instance.

We can also extend this to three variables, as shown in the truth table below. It gives the values of $ \neg A $, $ \neg B $, and $ \neg C $ for all possible values of $ A $, $ B $, and $ C $.

The Venn diagram for this instance is very similar:

$ \neg C $

As we can see, the not operation is very useful when dealing with Boolean values.

And $ \land $

The next Boolean logic operator we’ll cover is the and, or conjunction, operator. This operator works similar to the way we use “and” in our spoken language. If $ A $ is True, while $ B $ is also True, then we can say that both $ A $ and $ B $ are True. This would be written as $ A \land B $. Most programming languages use two ampersands && to represent the Boolean and operator, but some languages also include and as a keyword to denote this operator.

Here is a truth table giving the value of $ A \land B $ for all possible values of $ A $ and $ B $.

As we can see, the only time that $ A \land B $ is True is when both $ A $ and $ B $ are True.

Next, we can look at a Venn Diagram that represents this operation

$ A \land B $

As we can see, only the center of the Venn diagram is shaded, representing the parts of the diagram that are both in $ A $ and $ B $ at the same time.

This operation also easily extends to three variables. This truth table gives the value of $ A \land B \land C $ for all possible values of $ A $, $ B $, and $ C $.

The Venn diagram for this instance is very similar to the one above:

$ A \land B \land C $

Once again, we see that only the very center of the diagram is shaded, as expected.

Or $ \lor $

The third Boolean operator is the or, or disjunction, operator. It is somewhat similar to how we use the word “or” in our spoken language, with a major difference. This operator would be written as $ A \lor B $. Most programming languages use two vertical pipes || to represent the Boolean or operator, but some languages also include or as a keyword to denote this operator.

Consider ordering food at a restaurant as an example. On the menu, you might see the statement “Soup or Salad” as one of the options for your meal. This means that you must choose either “soup” or “salad” to go with your meal, but usually you aren’t allowed to have both (at least, without paying more).

Now, consider a similar statement, $ A \lor B $. If either $ A $ or $ B $ are True, we would say that $ A \lor B $ is also True. However, if both $ A $ and $ B $ are True, we would also say that $ A \lor B $ is True. So, the Boolean or operator will return True when both inputs are True, which differs from how we use it in spoken language.

Here is a truth table giving the value of $ A \lor B $ for all possible values of $ A $ and $ B $.

As we can see, the only time that $ A \lor B $ is False is when both $ A $ and $ B $ are False. As long as at least one of the values is True, the whole statement is True.

Next, we can look at a Venn Diagram that represents this operation

$ A \lor B $

As we can see, both circles are completely shaded, showing that $ A \lor B $ contains all items in either $ A $ or $ B $, or both $ A $ and $ B $ at the same time.

This operation also easily extends to three variables. This truth table gives the value of $ A \lor B \lor C $ for all possible values of $ A $, $ B $, and $ C $.

The Venn diagram for this instance is very similar to the one above:

$ A \lor B \lor C $

Once again, we see that all parts of the Venn diagram are shaded, except for the part outside of all the circles.

Exclusive Or $ \oplus $

The last Boolean operator we’ll cover is exclusive or, or exclusive disjunction. We’ll sometimes see this referred to as xor as well. When written, we use the $ \oplus $ symbol. However, not all programming languages have implemented this operator, so there is no consistently used symbol in programming.

This operator works in the same way that “or” works in our spoken language. Recall the “Soup or Salad” example from earlier. The exclusive or operation is True if only one of the inputs is True. If both inputs are True, the output is False.

Here is a truth table giving the value of $ A \oplus B $ for all possible values of $ A $ and $ B $.

As we can see, the result is True when either $ A $ or $ B $ are True, but it is False if both of them are True, or if both of them are False.

As a Venn diagram, it would look like this:

$ A \oplus B $

As we can see, the parts of the diagram in $ A $ and $ B $ are shaded, but the center part, which is in both $ A $ and $ B $, is not shaded.

This operation is most interesting when extended to three variables. This truth table gives the value of $ A \oplus B \oplus C $ for all possible values of $ A $, $ B $, and $ C $.

The Venn diagram for this instance is as follows:

$ A \oplus B \oplus C $

In this instance, we see the parts of the diagram representing items that are just in $ A $, $ B $, and $ C $ alone are shaded, as we’d expect. However, we also see the center of the diagram, representing items in $ A \land B \land C $ is also shaded. Interesting, isn’t it? Let’s see if we can break it down.

Just like we hopefully remember from mathematics, when we have multiple operations chained together, we must respect the order of operations. So, we can insert parentheses into the original statement to show how it would actually be calculated:

Now, let’s assume that all three of our variables are True, represented by $ T $. So, we can reduce the first part as follows:

$$((A \oplus B) \oplus C) $$ $$((T \oplus T) \oplus T) $$ $$(F \oplus T) $$

As we can see, since $ A $ and $ B $ are both True, we find that $ A \oplus B $ is False, as expected. Now, we can continue to reduce the expression:

$$ (F \oplus T) $$ $$ T $$

In this case, since only one of the two operands is True, the result of exclusive or would also be True. Therefore, $ A \oplus B \oplus C $ is True when all three variables are True. In short, a string of exclusive ors is True if an odd number of the variables are True, and it is False if an even number of variables are True.

Not all languages support an logical exclusive or. Alternate forms are $ ( A \lor B) \land \lnot (A \land B) $ or $ (\lnot A \land B) \lor (A \land \lnot B) $.

Comparators

Finally, it is worth discussing other operators that can result in a Boolean value. The most important of these operators are the comparators, which compare two values and return a result that is either True or False. We’ve definitely seen these operators before in mathematics, but may not have actually realized that they result in a Boolean value.

Below is a table giving the common comparators used in programming, along with an example of how they might be used:

That covers all of the basic operators and symbols in Boolean logic. On the next page, we’ll learn how to combine them together and create logical statements using the rules of Boolean algebra.

Boolean Algebra

Of course, one of the major goals of George Boole’s work was not only to create a system of logic that looked like math, but also to be able to apply some of the same techniques from math within that system. Boolean Algebra is a form of algebra that can be done on boolean expressions, and it contains many of the same laws and operations that we’ve already learned from algebra.

Boolean Expressions

A Boolean expression is any expression that results in a Boolean value. They consist of the values True and False, sometimes denoted as $ T $ and $ F $, literal values, and variables which are usually lower-case letters, combined using the operations discussed on the previous page. Here are a few examples:

$$ T \land x $$ $$ (\neg x \land y) \oplus z $$ $$ (5 < x) \land (y > 8) $$

Laws of Boolean Algebra

Boolean algebra contains many of the same laws found in algebra. Here is a table listing some of these laws with an example for each. If the law does not list a specific operation, then in general it will work for all operations.

De Morgan’s Laws

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There is one rule, not listed above, where Boolean Algebra differs greatly from other forms of algebra. That is how it deals with the negation, or inverse, of an entire statement. For this, we refer to the work of Augustus De Morgan, pictured above. De Morgan was expanding upon the work of George Boole, and published some additional laws for Boolean Algebra, which we collectively refer to as De Morgan’s Laws.

In Algebra, when we negate an entire statement, we must change the signs of each number in the statement. Consider the example below:

However, in Boolean Algebra, the same rules does not quite work:

For example, if we assign the value True to $ x $ and False to $ y $, we would be able to reduce the expression in this way:

$$ \neg(x \land y) \neq (\neg x) \land (\neg y) $$ $$ \neg(T \land F) \neq (\neg T) \land (\neg F) $$ $$ \neg(F) \neq F \land T $$ $$ T \neq F $$

As we can see, the two statements are not equal. Instead, De Morgan’s Laws tell us that we must also invert the operation, changing $ \land $ to $ \lor $ and vice-versa. Let’s look at a corrected version of the above example:

$$ \neg(x \land y) \iff (\neg x) \lor (\neg y) $$ $$ \neg(T \land F) \iff (\neg T) \lor (\neg F) $$ $$ \neg(F) \iff (F) \lor (T) $$ $$ T \iff T $$

So, we must add the following two laws to our table above:

That gives us a full suite of laws we can use when working in Boolean algebra.

A Worked Example

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Now that we’ve learned about many of the laws of Boolean algebra, let’s go through a worked example, just to see how we can find a Boolean expression from a truth table. Programmers perform this process many times while writing code, since most programs include several boolean expressions. Those expressions control how the program performs in certain situations, such as when to repeat a block of code or when to choose between multiple blocks of code.

Problem Statement

For this problem, let’s say we are working on a program to control smart lights. That program should turn the lights on if the light switch in the room is in the “ON” position. Similarly, it should turn on the lights if it detects there are people in the room using a motion sensor, regardless of whether the light switch is “ON” or “OFF”. However, it should respect a master switch, such that if the master switch is off, the lights can not be turned on at all.

How can we write a program that uses a Boolean expression to determine when to turn the lights on?

Truth Table

The first step is to create a truth table that describes the possible inputs and the desired outputs. For this example, we’ll assign input A to the light switch, input B to the motion sensor, and input C to the master switch. Using that, we can construct our truth table:

In this table, we see that there are exactly three situations that cause the lights to be turned on, which is where the Output column contains True. They are highlighted in bold in this example. First, on the fourth line of the table, if the motion sensor input B is True, and the master switch input C is also True, then the output should be True. Similarly, the sixth line shows that if the light switch A is True and the master switch C is True, then the output is True. Finally, the last line shows that if all inputs are True, the output is True and the lights should be on.

Does that cover all of the situations where the lights should be on? Most of the remaining lines are situations where the master switch C is False, so the lights should not be turned on in any of those situations. The only exception is the second line, where the master switch C is True, but none of the other inputs are True. In that case, the lights should remain off.

Venn Diagram

The next step is to make a Venn diagram. This step is not necessary, as we’ll see later, but it is a very helpful step to take when learning Boolean algebra for the first time. Each segment of the 3 variable Venn diagram corresponds to a particular line in the truth table, so we simply want to shade in each segment that corresponds to a line in the truth table where the output is True.

Let’s look at the first line where the output is True, which is the fourth line. In that line, we see that we need the part of the diagram that is contained in B and C, but not A. This is due to the fact that the inputs B and C are True, but input A is False on that line of the truth table. So, we’d shade in this segment of our Venn diagram:

The next line in the truth table where the output is True is the sixth line. In this line, we need the part that contains A and C but not B:

Finally, the last line in the truth table tells us that we must shade in the part of the diagram contained in all three circles, containing A and B and C together:

Now, we can put those sections together to find our overall Venn diagram for this statement:

So, we can see that there are three segments shaded in our Venn diagram, corresponding to three lines in the truth table where the output is True. This gives us a helpful visual way to look at our Boolean logic expression.

Boolean Expression from Venn Diagram

Now that we’ve created a Venn diagram for this example, we can use it to create our Boolean expression. For this step, we’ll need to break the shaded part of the Venn diagram down into parts we can describe, and put those pieces together in a way that they represent the diagram as a whole. Let’s see how that works.

First, looking at our diagram, one thing we might notice is that it can be broken up into two overlapping segments. The first segment is this one:

This diagram shows the part of the diagram that is included in both A and C. This is exactly the same as the 2 variable Venn diagram we saw on the previous page, especially if we ignore the circle for B. So, this diagram represents the Boolean expression $ A \land C $. That’s one piece of the puzzle.

The other segment we might see is this one:

Similarly, this diagram represents the Boolean expression $ B \land C $, since it is the part of the diagram that is included in both B and C.

If we overlap those two segments, we would see the following result (with overlapping segments shaded a bit darker):

This is effectively the same diagram as we found above, isn’t it? That’s what we are aiming for!

So, we know that we need an expression that represents $ A \land C $ and $ B \land C $ overlapped. If we recall back to the basic Boolean operations, we should hopefully remember that the or operation does just that. So, we can use $ \lor $ to connect our two pieces, making the final Boolean expression:

Now that we have our final expression, let’s go back to the problem statement and see if it matches. Recall that it says we would like the lights turned on if the light switch is on and the master switch is on, or if the motion sensor senses people and the master switch is on. If we replace the variables in the Boolean expression, we see the following:

That is exactly what we want! So, we found the correct Boolean expression for our problem statement.

Boolean Expression from Truth Table

We can also derive our Boolean expression directly from the data in the truth table, along with some of the Boolean Algebra laws we covered earlier in this chapter. Let’s go through an example of how that process works, just to see that we can get the same result.

In our truth table, we see that we should have three situations that provide output. The first is when B and C are True, while A is False. So, we could write that as the Boolean expression $ \neg A \land B \land C $.

Similarly, we can do the same for the other two lines of output, which produce the expressions $ A \land \neg B \land C $ and $ A \land B \land C $, respectively.

Finally, we’d like our output to be True if at least one of those situations is True. So, we can use the or $ \lor $ operation to connect them together into a single statement:

In fact, if we want, we can simply stop there. That statement is exactly equivalent to the one we found using the Venn diagrams above.

Further “Simplification”

However, it is very long and difficult to understand directly, and it doesn’t clearly reflect our problem statement. So, let’s see if we can reduce this expression using the laws of Boolean Algebra to an equivalent one that is easier to read.

First, we must use the law of Idempotence to duplicate one of our terms. From that law, we know that the following is true:

So, we can replace the final term with this equivalent statement. We can do this here since it won’t affect the final outcome. It is the rough equivalent to adding $ 0 $ to an existing mathematical expression. So, our new expression is

Next, we can use the law of Commutativity to rearrange the terms a bit. This is the same as rewriting $ 1 + 2 $ as $ 2 + 1 $, so it is a simple law to apply:

We can also use the law of Associativity to add a few extra parentheses, just for clarity:

Next, we can apply the inverse of the Distributive law on the first block of statements to “factor out” the statement $ (B \land C) $, leaving this result:

We can also do the same on the second block with $ (A \land C) $:

Next, we can use the Complement law to reduce both $ (\neg A \lor A) $ and $ (\neg B \lor B) $ to True:

Then, using the law of Identity, we know that $ x \land T \iff x $, so we can remove both instances of $ T $ in the expression:

Once again, we can apply the law of Commutativity to rearrange the terms to reach this final result:

There it is! We were able to use the laws of Boolean Algebra to prove that our Boolean expression found using the Venn diagrams is equivalent to the expression from the truth table. This process is very similar to the ones learned in an algebra class, but some of the laws are handled in a slightly different way.

An Alternative Approach

Venn Diagram Limitations

Not everyone finds the use of Venn diagrams easy or natural. Consider the following problem:

Determine if the value of the variable x is greater than 10, less than or equal to 30, and either divisible by both 2 and 3 or by 7.

A Venn diagram of this statement would look something similar to this example:

Unfortunately, it does not result in a graphic that is easily translatable to a Boolean logic statement. So, we’ll probably have to take another approach.

Pseudocode

Instead, we can use the original problem statement as the structure to build a pseudocode representation that can eventually be translated to any programming language. We’ll begin by breaking down the original problem statement into smaller parts, as shown below:

Determine if the value of the variable x is: 
  greater than 10
  less than or equal to 30 
  and either  
    divisible by both 2 and 3
    or by 7.

We’ve also added in a bit of indentation, just to make it easier to see the various parts of the statement.

Clearly the ands and ors in the original statement can be replaced with their Boolean equivalents. We’ll use capitalized AND, OR and NOT operators in text. Also, we can deduce that statements in a comma separated list should also be combined with AND, so we can update our statement as follows:

Determine if the value of the variable x is: 
  greater than 10
  AND less than or equal to 30 
  AND either  
    divisible by both 2 AND 3
    OR by 7.

Next, we should try to make each statement closely resemble a written expression in code by adding in the implied subject of each statement and making them explicit. In most cases, we’ll add the variable x to the statement, as shown here:

Determine if the value of the variable x is: 
  x greater than 10
  AND x less than or equal to 30 
  AND either  
    x divisible by 2 AND x divisible by 3
    OR x divisible by 7.

Notice how the statement divisible by both 2 and 3 was split into two parts. Each Boolean logic comparator requires a variable on each side, so we cannot write x divisible by 2 AND 3 as a valid statement. Instead, we have to split it into two statements, x divisible by 2 AND x divisible by 3. We also have to expand the line OR by 7 to clarify that it is also checking if x is divisible by 7, so we updated it to be x divisible by 7.

Now we can plug in the associated Boolean comparators and mathematical operators. Recall that we can check if a number is divisible by another number using the modulo operator; if that value modulo the divisor is 0, then we know the number is evenly divisible by the divisor. We’re also going to use the double equals sign == to denote equality, which is used in most programming languages.

Determine if the value of the variable x is: 
  x > 10
  AND x <= 30 
  AND either  
    x % 2 == 0 AND x % 3 == 0
    OR x % 7 == 0.

Once we have that, we can go through and add in any missing parentheses. Notice that we originally used some tabs separate the various parts of the original statement, and those should closely align with where we need to add parentheses.

So, one possible way to interpret this statement is as follows:

x > 10 AND x <= 30 AND ((x % 2 == 0 AND x % 3 == 0) OR x % 7 == 0)

This line of pseudocode is certainly easier translate into a programming language than using the Venn Diagram!

Computer Circuits

While Boolean logic is very important when writing computer code, it is also a major part of working with computer hardware as well. In fact, most electronic hardware today uses chips and circuits that are built directly upon the fundamental building blocks of Boolean logic.

Relay and Switching Circuits

¹

In 1937, a 21-year-old graduate student at MIT named Claude Shannon, pictured above, published his master’s thesis: “A Symbolic Analysis of Relay and Switching Circuits.” In that paper, he demonstrated how to build electric circuits which could perform all of the standard Boolean logic operations, using the presence or absence of an electric current or voltage to represent true and false in those circuits.

In addition, his work demonstrated that multiple circuits can be combined to perform simple mathematical operations on binary numbers, such as addition, subtraction, and even multiplication!

It is difficult to overstate the importance of Claude Shannon’s work in today’s modern world. Every electronic device we use is built upon the same fundamental concepts laid out by Shannon in the 1930s. In fact, one researcher described his work as “possibly the most important, and also the most famous, master’s thesis of the century.”²

Addition using Boolean Logic

Let’s look at an example of how Boolean logic can be used to perform mathematical operations. Here is a simple truth table showing addition using two binary bits as input. In this case, $ 0 $ represents false and $ 1 $ represents true:

The addition itself is performed by the xor operation. For example, if both inputs are $ 0 $, representing false, then the sum is $ 0 + 0 = 0 $, which is false as well. However, if one input is $ 1 $ and the other is $ 0 $, then the sum is $ 0 + 1 = 1 $ (which is the same as $ 1 + 0 = 0 $), so the xor operation would output true. In both of those cases, the carry bit is $ 0 $, since the sum does not require a bit to be carried forward to the left.

The interesting case is when both inputs are $ 1 $. In this case, the result is $ 1 + 1 = 2 $, where $ 2 $ is represented by $ 10 $ in binary. So, the sum result, represented by xor is false, but the carry bit, represented by the and operation, is true. So, the result would be $ 10 $, represented by the carry bit followed by the sum.

So, we can represent the mathematical addition operation $ A + B $ using these two Boolean logic expressions:

• Sum: $ A \oplus B $
• Carry: $ A \land B $

The corresponding circuit for this operation is known as a half adder.

We can then expand this truth table to include a third input, which is the carry bit from a previous addition.

From this truth table, we can find the following Boolean logic expressions for the sum and carry bits:

• Sum: $ (A \oplus B) \oplus C $
• Carry: $ (A \land B) \lor (B \land C) \lor (A \land C) $

This circuit is known as a full adder.

So, given two binary bits as inputs $ A $ and $ B $, along with the carry bit from a previous addition $ C $, we can use these two Boolean expressions to find both the sum and carry bits as output.

To find the sum of larger numbers, we can simply chain together multiple instances of these full adder circuits together, moving through the binary number from left to right, just like we do for normal addition. In modern computers, the central processing unit, or CPU, contains circuits very similar to these to perform each mathematical instruction required to execute a program.

Wikibooks has a great page dedicated to this topic for additional information: Practical Electronics/Adders

Summary

In this chapter, we learned all about Boolean logic, the corresponding rules for Boolean algebra, and how we can use those concepts to create our own Boolean logic expressions that we can use in our computer programs.

In the next chapters, we’ll see how we can use these expressions to control how our programs operate with programming constructs that allow our code to select between different branches or even repeat instructions as needed.

Programs as Flowcharts

We’ve created many different computer programs by now, but they have all had one thing in common: they only have a single execution path in the program. This means that, each time we run the program, we’ll execute the exact same pieces of code and perform the same operations on each variable. We may have different initial values stored in those variables, but that is really the only difference.

To better visualize this, we can actually think of the execution path of a program just like a flowchart. For example, here is a flowchart showing the execution path of a program that asks the user to input a number and then prints the square of that number.

However, what if we’d like our programs to be able to perform different actions, depending on the user’s input? Wouldn’t that be useful?

Branching Constructs

Let’s take a look at a second flowchart. For this program, we’ll have the user input a number. If the number is even, we’ll output even, but if it is odd, we’ll output odd. Let’s look at what this program might look like as a flowchart:

This flowchart uses a diamond-shaped block to indicate a decision we’d like our computer program to make. Inside the block, we see the Boolean logic expression x % 2 == 0, which will determine whether x is evenly divisible by $ 2 $. If so, the result of the modulo operation would be $ 0 $, so the entire statement would evaluate to true, indicating that x is an even number.

We also see two arrows coming from this block, one on the left if the statement is false, and another, on the right, if the statement is true. Each path leads to a different output, before being joined together at the end.

Nearly every programming language supports a method for running different parts of code based on the result of some Boolean logic expression, just like in this example. Collectively, these methods are known as conditional constructs, sometimes referred to as conditional statements or just conditionals. In the example above, the diamond-shaped block represents a conditional construct in that program.

Complex Decisions

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Of course, we can make even more complicated decisions in our programs. Let’s take a look at one more flowchart and see if we can understand what this program does:

At first glance, this flowchart may seem quite confusing. However, by looking closely at the decisions it makes and the corresponding output, we should realize that it is a program that plays the common “Rock, Paper, Scissors” game.

First, the program accepts two inputs, representing the symbols chosen by each player, and stores them in variables p1 and p2. Then, it checks to see if the inputs are equal. If so, the program declares the game to be a tie by outputting tie, and then it ends. If the inputs are not equal, then it can determine a winner.

Instead of trying to describe how the rest of the program works, let’s look at a few possible inputs and trace the program’s execution through the flowchart, just to see what it does.

First, let’s look at the case when player 1 chooses “rock” and player 2 chooses “paper”. So, our variables would be p1 = "rock" and p2 = "paper". Here’s a trace of the path that input would follow through the flowchart:

As we can see, first the program will check to see if the inputs are equal. Since they are not, it will follow the false branch to the left. Then, it will determine if player 1’s input was "rock". Since that is the case, it will follow the true branch to the right. After that, the program will test if p2 == "paper", which is also true. So, the program will follow the right branch, and output p2 wins. We can see that this output is indeed correct, since the rules of the game states that “paper covers rock”, meaning that player 2’s choice of paper will beat player 1’s choice of rock.

Let’s look at one other example. This time, player 1 chooses “scissors” and player 2 chooses “paper”. Here’s a flowchart representing our program with those inputs:

In this example, the program will first decide if the inputs are equal. They are not, so the program will once again follow the false branch to the left. Then, it will test to see if player 1’s input was "rock". In this case, the user input "scissors", so this test is false, and the program will choose the false branch to the left.

Next, it will try to determine if player 1’s input was "paper". Since that is also not the case, it will follow the false branch to the left once again.

At this point, our program knows that player 1 did not input either "rock" or "paper", so it can assume that the input must be "scissors". So, it will then check to see if player 2’s input was "rock". This is also false, so it will choose the false branch once again.

From earlier, it knows that player 2’s input is different from player 1, and player 2 did not input "rock". Since player 1’s input is assumed to be "scissors", that means that player 2 must have chosen "paper" as it is the only valid input left.

Therefore, this program has determined that player 1’s input was "scissors" and player 2’s input was "paper". By the rules of the game, “scissors cuts paper”, so player 1 wins. Our program will correctly output p1 wins!

As we can see, the ability to make decisions in a computer program is one of the most important building blocks we need to build more elaborate and complex programs. In this chapter, we’ll learn about all of the different ways we can write computer programs to make decisions and perform different actions based on those decisions using conditional constructs.

If Statements

The first type of conditional construct we’ll cover is the if statement. This type of statement allows us to build a block of code which will only be executed if the given Boolean expression evaluates to true.

Here’s a simple flowchart that shows an if statement as the conditional construct:

This flowchart represents a program which will ask the user for a number as input, then print that number as output only if the number is greater than $ 0 $. Then, the program will print Goodbye and terminate. So, if the user inputs -5, the program will only print Goodbye. However, if the user inputs 7, then the program will first print 7 followed by Goodbye. As we can see, the program will execute the section of code that prints the value of the variable if and only if the value of x > 0 is true. Otherwise, it will skip that code and continue with the rest of the program.

Notice that this statement does not include any operations in the case that x > 0 is false. Instead, the false branch points downward, and merges with the true branch after the program outputs the value of x. This is the main difference between an if statement and an if-else statement, which we’ll cover on the next page.

Most programming languages implement an if statement in a format similar to this:

<before code block>
if <Boolean expression> {
    <if code block> or <True block>
    }
<after code block>

The program is initially executing code in the <before code block> section. Once it reaches the if keyword, it will then evaluate the <Boolean expression> to a value of either true or false. If the expression is true, then it will execute the code in the <if code block>, followed by the code in the <after code block>. If the expression is false, the program will simply continue executing code in the <after code block>, bypassing the other block entirely.

IF <condition> THEN <action>

if (condition) {
    <action>
}

If-Else Statements

Next, let’s look at the if-else statement. This statement allows us to choose between two different blocks of code, one to be executed when the Boolean logic expression evaluates to true, and a different block if the expression evaluates to false.

Here’s a simple flowchart that shows an if-else statement as the conditional construct:

This program is very similar to the one shown on the previous page, with one major difference. Once again, this program will ask the user for a number as input, then print that number as output if the number is greater than or equal to $ 0 $. However, if the input value is less than $ 0 $, the program will instead print the inverse of that value by multiplying it by $ -1 $ before printing. Finally, the program will print Goodbye and terminate.

So, if the user inputs 7, the program will just print 7 followed by Goodbye. However, if the user inputs -5, then the program will calculate $ -1 * -5 $ and print 5, followed by Goodbye. As we can see, the program will choose which block of code to execute depending on the Boolean value that results from evaluating x >= 0. Once it has executed one of those two blocks, then the program will continue with the rest of the code.

Most programming languages implement an if-else statement in a format similar to this:

<before code block>
if (Boolean expression) { 
    <if code block> or <True code block>
}
else {
    <else code block> or <False code block>
}
<after code block>

The program is initially executing code in the <before code block> section. Once it reaches the if keyword, it will then evaluate the <Boolean expression> to a value of either true or false. If the expression is true, then it will execute the code in the <then code block>, followed by the code in the <after code block>. If the expression is false, the program will execute code in the <else code block>, followed by the code in the <after code block>.

It is important to note that it is impossible for the program to execute both the <True code block> and the <False code block> during any single execution of the program. It must choose one block or the other, but it cannot do both. So, if we want each block to perform the same action, we’ll have to include the appropriate code in both blocks.

Other Branching Statements

Many programming languages also provide other conditional constructs that perform these same operations in different ways. However, each of these constructs can also be built using just if and if-else statements, so it is not necessary to use these constructs themselves to achieve the desired result. In many cases, they are simply provided as a convenience to the programmer in order to make the code simpler or easier to understand.

Switch

Some programming languages, such as C and Java, include a special type of conditional construct known as a switch statement, sometimes referred to as a case statement. Instead of using a Boolean value, which can only be true or false, a switch statement allows our program to choose a block of code to execute based on the many possible values of a variable, traditionally an integer value.

This flowchart shows what a switch statement might look like in a program:

In this example, the program will examine the value of the variable x and use it to choose a case, which is a code block that would be executed. Here, it would simply output a different response, depending on the value of x. Notice that the flowchart is essentially using several if statements to accomplish this task, which is essentially what the computer would do when executing this program. In addition, the program includes a special default case, which is executed if the value of x does not match any of the other cases.

In code, a Switch Statement may have this general structure:

switch <variable>:
  case <value 1>: <code block 1>
  case <value 2>: <code block 2>
  case <value 3>: <code block 3>
  ...
  default: <default code block>

Depending on the programming language used, it is possible to execute multiple code blocks inside a switch statement, so we may need to consult the documentation for our chosen programming language to understand how these statements work.

Ternary Conditional Operator

Many programming languages also include a special operator, known as a ternary conditional operator, sometimes referred to simply as a ternary operator, that is effectively a shortcut for a simple if-else statement that produces a single value. Here’s a flowchart showing an example:

In this example, the program accepts two variables, x and y, as input. Then, it will set the value of a third variable, z, to the maximum value of x and y. It does so by testing if x > y. If so, it will set z = x; otherwise it will set z = y.

In general, there are two different ways that this operator is implemented. In Java and other programming languages similar to C, it looks like this example:

<variable> = <boolean expression> ? <true expression> : <false expression>

In Python, the ternary conditional operator looks just a bit different:

<variable> = <true expression> if <boolean expression> else <false expression>