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.