Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!usc!ginosko!uunet!dgis!generous
From: generous@dgis.daitc.mil (Curtis Generous)
Newsgroups: comp.lang.c
Subject: Re: swap(x,y)
Message-ID: <40@dgis.daitc.mil>
Date: 22 Aug 89 12:46:51 GMT
References: <MYwDEFy00WB842JEUx@andrew.cmu.edu>
Organization: DTIC Special Projects Office (DTIC-SPO), Alexandria VA
Lines: 32

tg1e+@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
-- 
Curtis C. Generous
DTIC Special Projects Office (DTIC-SPO)
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