Finding The Area Of Circle In C Programming

#include <stdio.h>
#define pi 3.14

int main()
{
    float a,c,r;
    printf("\nEnter the radius :");
    scanf(" %f", &r);
   
    a=pi*r*r;
    c=2*pi*r;
     printf("\nArea : %f", a);
    printf("\nCircumference : %f", c);

    return 0;
}