swap() using pass by pointer

#include <iostream>

using namespace std;

void swap(int *p1, int *p2);

int main()
{
    cout << "Enter 2 integers: ";
    int v1, v2;
    cin >> v1 >> v2;
    cout << "v1 == " << v1 << ", v2 == " << v2 << endl;
    swap(&v1, &v2);
    cout << "after swap:" << endl;
    cout << "v1 == " << v1 << ", v2 == " << v2 << endl;
    return 0;
}

void swap(int *p1, int *p2)
{
    int temp = *p1;
    *p1 = *p2;
    *p2 = temp;
}