A macro is a pre-processor directive which is a program that processes the source code before it passes through the compiler. These are placed in the source program before the main. To define a macro, # define statement is used. This statement, also known as macro definition takes the following general form:
define identifier string
The pre-processor replaces every occurrence of the identifier in the source code by the string. The preprocessor directive definition is not terminated by a semicolon. For example
define COUNT 100 will replace all occurrences of COUNT with 100 in the whole program before compilation.
