Path: utzoo!utgpu!watserv1!watmath!att!dptg!ulysses!andante!alice!ark
From: ark@alice.UUCP (Andrew Koenig)
Newsgroups: comp.lang.c
Subject: TRUE and FALSE (was: NULL as a string terminator)
Message-ID: <11215@alice.UUCP>
Date: 20 Aug 90 23:02:46 GMT
References: <24141@megaron.cs.arizona.edu> <134@blekko.UUCP> <12249@netcom.UUCP>
Organization: AT&T Bell Laboratories, Liberty Corner NJ
Lines: 36

In article <12249@netcom.UUCP>, ergo@netcom.UUCP (Isaac Rabinovitch) writes:

> On the other hand, you can say (and I used to) that using 1 and
> 0 instead of TRUE and FALSE is a similar "familiar practice", since any
> competant C programmer knows that C booleans are just integers.  
> In this case it probably makes a big difference that TRUE and FALSE are
> ordinary English words, not obscure acronyms.

Unfortunately, using TRUE and FALSE opens a great gaping hole:
one would expect that

	x == TRUE

would mean the same as

	x != FALSE

but of course it doesn't -- at least not if you use the usual C
convention that 0 is false and any other value is true.

> I recently came up against a similar clash of "familiar concepts" in
> C.  People were arguing (was it in this group?) over why programmers
> use "i" instead of "i == 0".

Well, for one thing,

	if (i) foo();

and

	if (i == 0) foo();

mean precisely the opposite of each other.  :-)
-- 
				--Andrew Koenig
				  ark@europa.att.com