#include <iostream>

using namespace std;

void myswap(int &x, int &y) {
    int temp;

    temp=x;
    x=y;
    y=temp;

    return;
}

int main()
{
    int i,j,temp;

    i=10;
    j=20;

    cout << i << endl;
    cout << j << endl;

    cout << endl;

    myswap(i,j);

    cout << i << endl;
    cout << j << endl;

    return 0;
}