What is a macro, and how do you use it?

A macro is a preprocessor directive that provides a mechanism for token replacement in your source code. Macros are created by using the #define statement. Here is an example of a macro: Macros can also utilize special operators such as the stringizing operator (#) and the concatenation operator (##).The stringizing operator can be used to convert macro parameters to quoted strings, as in the following example: #define DEBUG_VALUE(v) printf(#v � is equal to %d.n�, v) In your program, you can check the value of a variable by invoking the DEBUG_VALUE macro: ... int x = 20; DEBUG_VALUE(x); ... The preceding code prints �x is equal to 20.� on-screen. This example shows that the stringizing operator used with macros can be a very handy debugging tool.