gcd.cpp

#include <cassert>

int gcd(int a, int b) {
    assert(b < a);
    assert(b >= 0);
    assert(a >= 0);
    
    if (b == 0) {
        assert(a > 0);
    
        return a;
    }
    int result = gcd(b, a % b);
    
    assert(result > 0);
    return result;
}