PTA ----- 圆形体体积计算器

#include <stdio.h>
#include <math.h>
#define PI 3.14159265358979
void main()
{
    double x = 4.0, y = 3.0, e = 1.0, r, h;
    int n, i = 0;
    while (1)
    {
        printf("1-Ball\n");
        printf("2-Cylinder\n");
        printf("3-Cone\n");
        printf("other-Exit\n");
        printf("Please enter your command:\n");
        scanf("%d", &n);
        if (n == 1)
        {
            printf("Please enter the radius:\n");
            scanf("%lf", &r);
            printf("%.2lf\n", (x / y * 1.0) * PI * pow(r, 3) * 1.0);
        }
        else if (n == 2)
        {
            printf("Please enter the radius and the height:\n");
            scanf("%lf %lf", &r, &h);
            printf("%.2lf\n", h * PI * pow(r, 2) * 1.0);
        }
        else if (n == 3)
        {
            printf("Please enter the radius and the height:\n");
            scanf("%lf %lf", &r, &h);
            printf("%.2lf\n", 1 / y * PI * r * r * h * 1.0);
        }
        else break;
    }
}