/* To find the area of perimeter using function */
/* formula: 2 pi r  */
#include< stdio.h>
#include< conio.h>
# define pi 3.14         /* preprocessor */
main()
{
	int radius;
	float area,result;
	clrscr();
	printf("enter radius\n");
	scanf("%d",&radius);
	perimeter(radius,&result);
	printf("\n Perimeter=%f",result);
	getch();
}
perimeter(int r,float *result)
{
	*result=pi*r;
}