Up to this point, we’ve mainly been developing our programs without any underlying patterns between them. Each program is custom-written to fit the particular situation or use case, and beyond using a few standard data structures, the code and structure within each program is mostly unique to that application. In this chapter, we’re going to learn about software design patterns, a very powerful aspect of object-oriented programming and a way that we can write code that is more easily recognized and understood by other developers. By using these patterns, we can see that many unrelated programs can actually share similar code structures and ideas.

Some of the key terms we’ll cover in this chapter:

• Software Design Patterns
• The Gang of Four
• Creational Patterns
  • Builder Pattern
  • Factory Method Pattern
  • Singleton Pattern
• Structural Patterns
  • Adapter Pattern
• Behavioral Patterns
  • Iterator Pattern
  • Template Method Pattern

After reviewing this chapter, we should be able to recognize and use several of the most common design patterns in our code.