P57852: Màxim comú divisor de quatre

#include <iostream>
using namespace std;


int mcd4(int a, int b, int c, int d) {
    if (a < 0) a = -a;
    if (b < 0) b = -b;
    if (c < 0) a = -c;
    if (d < 0) b = -d;
    if (b > a) {
        int aux = a;
        a = b;
        b = aux;
    }
    if (d > c) {
        int aux1 = c;
        c = d;
        d = aux1;
    }
    int r1;
    while (b != 0) {
        r1 = a%b;
        a = b;
        b = r1;
    }
    int r2;
    while (d != 0) {
        r2 = c%d;
        c = d;
        d = r2;
    }
    if (c > a) {
        int aux1 = a;
        a = c;
        c = aux1;
    }
    int r;
    while (c != 0) {
        r = a%c;
        a = c;
        c = r;
    }
    return a;
}

//Pre: Llegeix 4 nombres
//Post: Calcula l'mcd
int main() {
    int a, b, c, d;
    cin >> a >> b >> c >> d;
    cout << mcd4(a, b, c, d) << endl;
}