#include <stdio.h>
#include <math.h>

float pi=3.14159246;

int func(float x,float y)
{

        x = pi*y*y;
}
int main(void)
{
        float r,a;
        printf ("\n\nEnter with previos radius value\n\n ");
        scanf ("%f",&r);
        func(a,r);
        printf ("\n\nThe area value is:  %.3f \n\n",a);
        return(0);
}