/* 
 * program to compute GCD using recursive version of Euclid's
 * algorithm.
*/
#include<stdio.h>

int gcd(int a, int b);

int main(void) {
    int a, b, r;

    printf("Enter values for a and b, one per line\n");
    scanf("%d", &a);
    scanf("%d", &b);

    if ((a == 0) && (b == 0)) {
        printf("Cannot both be 0\n");
        return 0;
    }

    printf("\nYou entered:\n");
    printf("%d\n", a);
    printf("%d\n", b);
    r = gcd(a, b);
    printf("\nGCD of a and b:\n");
    printf("%d\n", r);

    return 0;
}

int gcd(int a, int b) {
    if (b == 0) {
        return a;
    }
    else {
        return gcd(b, a%b);
    }
}