C program to find perimeter of circle

/* To find perimeter of circle */ 

#include<stdio.h> 

#define PI 3.1415927 

void main() 

{ 

 float peri, r; 

 printf("Enter value for radius\n"); 

 scanf("%f",&r); peri=2*PI*r; 

 printf("Perimeter=%f\n",peri); 

}