C Program to show use of #define Preprocessor Directives

#include <stdio.h>

#include <conio.h>

 

#define PI 3.141

 

int main(){

    int radius;

    float circumference;

    printf("Enter the radius of circle\n");

    scanf("%d", &radius);

     

    circumference = 2*PI*radius;

     

    printf("Circumference of Circle = %f", circumference);

     

    getch();

    return 0;

}