C++ Swapping Pointers

Question

I\'m working on a function to swap pointers and I can\'t figure out why this isn\'t working. When I print out r and s in the swap function the values are swapped, which lea

Answer 1

The accepted answer by taocp doesn't quite swap pointers either. The following is the correct way to swap pointers.

void swap(int **r, int **s)
{
    int *pSwap = *r;
    *r = *s;
    *s = pSwap;
}

int main()
{
    int *p = new int(7);
    int *q = new int(9);

    cout << "p = " << std::hex << p << std::endl;
    cout << "q = " << std::hex << q << std::endl << std::endl;

    swap(&p, &q);

    cout << "p = " << std::hex << p << std::endl;
    cout << "q = " << std::hex << q << std::endl << std::endl;

    cout << "p = " << *p << " q= " << *q << endl;
    return 0;
}

Output on my machine:

p = 0x2bf6440
q = 0x2bf6460

p = 0x2bf6460
q = 0x2bf6440

p = 9 q= 7