#include <iostream>
using namespace std;

void swapv(int x, int y) {
    int temp = x; x = y; y = temp;
}

void swapp(int *px, int *py) {
    int temp = *px; *px = *py; *py = temp;
}

void swapr(int & x, int & y) {
    int temp = x; x = y; y = temp;
}

int main() {
    int a = 13, b = 7;
    int *pa = &a, *pb = &b;
    cout << "a=" << a << ", b=" << b << endl;
    cout << "Calling swapv" << endl;
    swapv(a, b);
    cout << "a=" << a << ", b=" << b << endl;
    cout << "Calling swapp" << endl;
    swapp(&a, &b);
    cout << "a=" << a << ", b=" << b << endl;
    cout << "Calling swapr" << endl;
    swapr(a, b);
    cout << "a=" << a << ", b=" << b << endl;
}