C/C++ Swap without using extra variable

[code]/**
* Swap the parameters with a temp variable.
* @param a The first parameter.
* @param a The second parameter.
*/
void swap(int& a, int& b)
{
    int temp = a;
    a = b;
    b = temp;
}

[code]/**
* Swap the parameters without a temp variable.
* Warning! Susceptible to overflow/underflow.
* @param a The first parameter.
* @param a The second parameter.
*/
void swapNoTemp(int& a, int& b)
{
    a -= b;      // a = a - b
    b += a;      // b = b + (a - b), b gets the original value of a
    a = (b - a); // a = a - (a - b), a gets the original value of b
}