swap(x,y)

[Curtis Generous]

tg1e+ at andrew.cmu.edu (Timothy R. Gottschalk) writes:
>       To swap two variables x,y in C without using a temporary variable:
>       /* begin swap */
>       x += y;
>       y = x - y;
>       x -= y;
>       /* end swap */
>       Just curious...(this looks pretty valid) does anyone know an even
>simpler method?  I would never program this way -- it's more of a theory
>question.  I've been told that it can't be done (???).
>Tim Gottschalk
>Pgh, PA

Saw this come across the net a few months back.  Don't know where it came
from.

	swap( a , b )
	    unsigned *a, *b;
	{
	    *a ^= *b ;
	    *b ^= *a ;
	    *a ^= *b ;
	}

I'm not sure it is any simpler, just another original approach.

--curtis
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