Path: utzoo!attcan!uunet!cs.utexas.edu!wuarchive!husc6!m2c!wpi!oesterle
From: oesterle@wpi.wpi.edu (Shawn H. Oesterle)
Newsgroups: comp.lang.c
Subject: Brain Teaser
Keywords: { void * x, * y; x <-> y; }
Message-ID: <10289@wpi.wpi.edu>
Date: 27 Mar 90 18:23:30 GMT
Reply-To: oesterle@wpi.wpi.edu (Shawn H. Oesterle)
Organization: Worcester Polytechnic Institute, Worcester, MA
Lines: 33


Problem:
	Swap two pointers without using a third pointer.


Example:
	{
		void * x, * y, * tmp;

		tmp = x;
		x = y;
		y = x;
	}

	Make a piece of code which has the same effect as this, but without
	using the 'tmp' variable (in C, of course).


Hint:
	Two numbers may be swaped without using any other memory by executing
	the following statements:

	int x, y;	/* or you can chose double, long, etc. */

	x += y;
	y = x - y;
	x -= y;


Answer:
	I don't know, that's why I'm asking you!
	
Shawn Oesterle {oesterle@wpi.wpi.edu}