what # does in define c code example

Example 1: #define in c

#include <stdio.h>

#define NAME "TechOnTheNet.com"
#define AGE 10

int main()
{
   printf("%s is over %d years old.\n", NAME, AGE);
   return 0;
}

Example 2: what is mean of define in c language

#define is a C preprocessor directive used to define macros. ... The preprocessor directives are used to provide general instruction or required data which is used inside a program. A macro is a block of code which has been given a name. Any occurance of that name is replaced by the value of the macro.