pUZ4wR - Online C Compiler & Debugging Tool

#include <stdio.h>

int main(void) {

    int a, b, c;
    scanf("%d %d %d", &a, &b, &c);

    switch (c) {
    case 1:
        printf("%d + %d = %d", a, b, a + b);
        break;

    case 2:
        printf("%d - %d = %d", a, b, a - b);
        break;

    case 3:
        printf("%d * %d = %d", a, b, a * b);
        break;

    case 4: {
        if (b == 0) {
            printf("not defined");
            break;
        }

        int div = a / b;
        int mod = a % b;

        switch (mod == 0) {
        case 1:
            printf("%d ÷ %d = %d", a, b, div);
            break;
        case 0:
            printf("%d ÷ %d = %d ... %d", a, b, div, mod);
            break;
        }
        break;
    }

    default:
        printf("not defined");
        break;
    }
}