#define preprocessor

The #define preprocessor allows us to define symbolic names and constants. A quick example

	#define PI 3.14159

   #define PI 3.14159

   main()
   {
       int r=10;
       float cir;
       cir = PI * (r*r);   
   }

This feature is partically usefull for defining 'magic' numbers.

See Also:

• A related C keyword is enum which can be used to build lists of aliases.

• Another related C keyword is const.

• An advanced use of #define is in the creation of macros.
• Predefined Macros

Examples:

example program.

Conflict between enum and #define.