C/Type Qualifiers

C Type Qualifiers

C type qualifiers add special properties to the variables being declared. C provides the following two keywords:

• const: the const qualifier is used to indicate the variable value can not be changed after its initialization. As an alternative, the #define preprocessor directive can be used to define constant values and these will consume no memory space.

• volatile: the volatile qualifier indicates that variable values can be changed without the current program's knowledge and so the compiler should not optimize away uses of that variable.

Note: a Standard conforming compiler can ignore these qualifiers; nevertheless, it must issue a message when an attempt is made to alter an object declared as const.