using ^= to swap two integers

[Arnold Robbins]

I blew it:

>>  Jon Shapiro
>   me

>> 	To exchange two items without an intermediate variable, try:
>> 
>> 	b ^= a ^= b ^= a
>> 
>> Jon Shapiro
>
>However, if a == b when you start out, you end up with a == 0 && b == 0.

I tried it, and in fact it does end up swapping them, but since they were
equal in the first place, it is a null op.  Several people have pointed out
to me that I was wrong, so please, no more mail.  I goofed.

(Here is the program which proved me wrong.)
main()
{
	int a = 3, b = 3;

	b ^= a ^= b ^= a;

	printf ("a = %d\tb = %d\n", a, b);
}
-- 
Arnold Robbins
CSNET:	arnold at gatech	ARPA:	arnold%gatech.csnet at csnet-relay.arpa
UUCP:	{ akgua, allegra, hplabs, ihnp4, seismo, ut-sally }!gatech!arnold

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