C #define

The #define preprocessor directive is used to define constant or micro substitution. It can use any basic data type.

Syntax:

Let's see an example of #define to define a constant.

#include <stdio.h>
#define PI 3.14
main() {
   printf("%f",PI);
}

Output:

3.140000

Let's see an example of #define to create a macro.

#include <stdio.h>
#define MIN(a,b) ((a)<(b)?(a):(b))
void main() {
   printf("Minimum between 10 and 20 is: %d\n", MIN(10,20));  
}

Output:

Minimum between 10 and 20 is: 10

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