Pointer vs Reference Swap

#include <iostream>

// Define swapPtr(int* a, int* b)
void swapPtr( int *a, int*b)
{
    *a = *a+*b;
    *b = (*a-*b);
    *a = (*a-*b);
}
// Define swapRef(int& a, int& b)
void swapRef(int &a, int& b)
{
    a = a+b;
    b= (a-b);
    a =(a-b);
}

int main() {
    int x, y;
    std::cin >> x >> y;

    int a = x, b = y;
    swapPtr(&a, &b);
    std::cout << "After swapPtr: a=" << a << " b=" << b << "\n";

    int c = x, d = y;
    swapRef(c, d);
    std::cout << "After swapRef: a=" << c << " b=" << d;

    return 0;
}