#include <iostream>

using namespace std;

int global = 10;

void func(int &x, int y)
{
    x = x - y;
    y = x * 10;
    cout << x << " , " << y << '\n';
}

int main()
{
    int global = 7;

    func(::global, global);
    cout << global << " , " << ::global << '\n';
    func(global, ::global);
    cout << global << " , " << ::global << '\n';
}