16.2.1 Built-in bool type

C++ introduced a built-in boolean data type called bool. The presence of this new type makes it unnecessary to use an int with the values 0 and 1 and improves type safety. The two possible values of a bool are true and false--these are reserved words. The compiler knows how to coerce a bool into an int and vice-versa.

If your compiler does not have the bool type and false and true keywords, an alternative is to produce such a type using a typedef of an enumeration representing the two possible values:

enum boolvals { false, true }; typedef enum boolvals bool;

What makes this simple alternative attractive is that it prevents having to adjust the prolific amount of code that might use bool objects once your compiler supports the built-in type.