[Templates That Are Usually Used]Greatest Common Divisor

#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;

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

int main()
{
    int a, b, c;
    cin >> a >> b;
    c = gcd(a, b);
    cout << c << endl;
    return 0;
}

//优化：

int gcd(int x, int y)
{
    return y == 0 ? x : gcd(y, x%y);
}