swapping variables

I don't know why you would want to use xor for this, or why you don't WANT to cheat, because if you would start using xor, you're using xor instead of the 3rd variable, and you would still cheat in that way.

Just use the 3rd variable imo, because using xor would still be cheating... and would make things more complicated then they need to be...

So: You can never swap them without cheating in one way the another...