Booleans

Booleans

Java has a simple type, called boolean, for logical values. It can have only one of two

possible values, true or false. This is the type returned by all relational operators, such

as a < >. boolean is also the type required by the conditional expressions that govern the

control statements such as if and for.

Here is a example program for the boolean type:

THEJAVA

LANGUAGE

// Demonstrate boolean values.

class BoolTest

{

public static void main(String args[])

{

boolean b;

b = false;

System.out.println("b is " + b);

b = true;

System.out.println("b is " + b);

// a boolean value can control the if statement

if(b) System.out.println("This is executed.");

b = false;

if(b) System.out.println("This is not executed.");

// outcome of a relational operator is a boolean value

System.out.println("10 > 9 is " + (10 > 9));

}

}

The Output will be:

b is false

b is true

This is executed.

10 > 9 is true

There are three interesting things to notice about this program. First, as you can see,

when a boolean value is output by println( ), “true” or “false” is displayed. Second,

the value of a boolean variable is sufficient, by itself, to control the if statement. There is no need to write an if statement like this: