Swapping Two Integer Variables Without Using a Temp Variable

The first time I heard this question, I thought it was a joke of some kind. I never thought such was possible.

Turned out to be possible and even faster than the normal technique, here you go:

Let X be an integer variable.
Let Y be another integer variable.
X = X xor Y
Y = X xor Y
X = X xor Y

Wont buy it? Then try it out for yourself.

One more technique, you can use the - (minus) operator instead, but be careful not to step over the integer max and min limits. Here you go:

(eg. X = 12, Y = 7)
X = X - Y ( X is now 5)
Y = X + Y ( Y is now 12)
X = Y - X ( X is now 7)
(result: X = 7, Y = 12, Voila! Swapped)

Hmmmm. Coming to think of a practical use. The only way such would be useful is to swap two large memory binary buffers.

This swapping enhancement breaks the common myth of 'its either memory or speed, but not both'. The swapping algorithm you just saw proves better in both memory consumption and performance gain.