Boolean Values

The types we have seen so far are pretty big. There are a lot of integers in the world, and even more floating-point numbers. By comparison, the set of characters is pretty small. Well, there is another type in C++ that is even smaller. It is called boolean , and the only values in it are true and false . We were already using these values without knowing that they are boolean.

Without thinking about it, we have been using boolean values for the last couple of chapters. The condition inside an if statement or a while statement is a boolean expression. Also, the result of a comparison operator is a Boolean value. For example :

if ( Max.dX < 0 )

{

// do something

}

The operator < compares two doubles and produces a boolean value.

The values true and false are keywords in C++, and can be used anywhere a boolean expression is called for. For example:

if ( true )

{

// always executed

}

if ( false )

{

// never executed

}