Other Types

Beyond numbers, there are a few other primitive data types in Java. Let’s take a quick look at them and see how they can be used in our programs.

Boolean

Java supports a primitive data type named boolean that can only store two values: true and false. As we might expect, we can use these boolean variables to store answers to questions in our program, such as “Is x greater than y?” At this point, we won’t use boolean variables for much in our programs, but in a later module we’ll cover the basics of boolean logic and learn how to use these variables to control how our program runs.

Character

Java also has a char data type, which can be used to store a single character of text. It uses the 16-bit Unicode format to store the data, which is the same as ASCII for simple characters and commands.

Declaring & Assigning

To declare a variable using these data types, the format is the same as the numerical data types:

boolean t;
char c;

We can also assign values to each variable. For example, to assign a value to a boolean variable, we could do this:

boolean t;
t = true;
boolean f = false;

Notice that both true and false are keywords in Java, which means that we won’t have to put them in quotation marks to use them. These values can be used to directly represent the boolean values True and False, respectively. Some programming languages, most notably C, do not support boolean values in this way, but Java includes them as keywords.

For characters, the process is similar:

char c;
c = 'a';
char d = 'B';

Notice that we use a single quotation mark ' around character values in our code. This is very important to remember! In our Hello World example, we used double quotation marks " around strings, or sentences of text. For a single character, however, we only use a single quotation mark.

char c = "a";
System.out.println("c");

char c = 'a';
System.out.println("c");