In the C Programming Language, the #define directive allows the definition of macros within your source code. These macro definitions allow constant values to be declared for use throughout your code.
Syntax-
#define NAME value
or
#define NAME expression
-Where NAME is the keyword or thing that you can call to get the value or expression.
Note:
Do not put semicolon(;) after the #define line
program-
#include < stdio.h>
#define name "r4r.in"
#define age 10
int main()
{
printf("Value of name is %s\n",name);
printf("Value of age is %d",age);
return 0;
}
Value of name is r4r.in
Value of age is 10