3.

3.#

 1#include <iostream>
 2
 3using namespace std;
 4
 5void fun(int& x, int y) {
 6  x = y % 9;
 7  y = x % 3;
 8  x++;
 9  cout << x << '\t' << y << endl;
10}
11
12int main() {
13  int x = 1, y = 10;
14  fun(y, x);
15  cout << x << '\t' << y << endl;
16  fun(x, x);
17  cout << x << '\t' << y << endl;
18}