Find Perimeter of a Circle. Take the value of the radius from user.

#include<stdio.h>
#define pi 3.14

void main()
{
    int r;
    float p;
    printf("Enter the value of radius: ");
    scanf("%d", &r); 
    p=2*pi*r;
    printf("Perimeter=%f",p);
}

   

Output
Enter the value of radius: 9
Perimeter=56.520000