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

#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

double cylindervolume(double radius, double height)
{
    return M_PI*radius*radius*height;
}

int main()
{
    double r = 1.0, h = 1.0;
    printf("Cylinder Volume Calculation\n\n");
    while (r > 0.0 && h > 0.0)
    {
        printf("Input the radius: ");
        scanf("%lf", &r);
        printf("Input the height: ");
        scanf("%lf", &h);
        printf("\nVolume = %g\n\n",cylindervolume(r, h));
    }
    return 0;
}