#include <stdio.h>

#define PI 3.141592653589793

void circumference(double r) {
    printf("Circumference for radius %.2f = %.2f\n", r, 2 * PI * r);
}

void area(double r) {
    printf("Circle Area for radius %.2f = %.2f\n", r, PI * r * r);
}

void volume(double r) {
    printf("Sphere Volume for radius %.2f = %.2f\n", r, (4.0 / 3.0) * PI * r * r * r);
}

int main(void) {
    void (*calc[3])(double) = {circumference, area, volume};
    int choice;
    double radius;

    printf("Enter 0 for Circumference, 1 for Circle Area, 2 for Sphere Volume: ");
    scanf("%d", &choice);

    if (choice >= 0 && choice <= 2) {
        printf("Enter radius: ");
        scanf("%lf", &radius);
        (*calc[choice])(radius);
    } else {
        puts("Invalid choice.");
    }
    return 0;
}