#include <iostream>
using namespace std;

void myswap(int &a, int &b){
    int temp;

    temp=a;
    a=b;
    b=temp;
}


int main() {
    int a=10;
    int b=20;

    cout << "a: " << a << endl;
    cout << "b: " << b << endl;
    myswap(a,b);

    cout << endl;

    cout << "a: " << a << endl;
    cout << "b: " << b << endl;

    return 0;
}