Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!mcnc!unc!steele From: steele@unc.cs.unc.edu (Oliver Steele) Newsgroups: comp.lang.c Subject: Re: Defining TRUE and FALSE Message-ID: <832@unc.cs.unc.edu> Date: Sun, 19-Jul-87 14:16:42 EDT Article-I.D.: unc.832 Posted: Sun Jul 19 14:16:42 1987 Date-Received: Wed, 22-Jul-87 00:42:21 EDT References: <13851@watmath.UUCP> <632@itsgw.RPI.EDU> <13259@topaz.rutgers.edu> <6123@brl-smoke.ARPA> <208@vianet.UUCP> Reply-To: steele@unc.UUCP (Oliver Steele) Organization: University of North Carolina, Chapel Hill Lines: 24 Keywords: boolean, true, false In article <208@vianet.UUCP> devine@vianet.UUCP (Bob Devine) writes: > I've used this method [writing "flag++" to set the boolean "flag" to >true] many times -- but with a purpose in mind. Doing it with a test >allows a easy check for multiple use of a option. For example, W_flag >is set to 0 at the start and the following code is inside of a getopt() >loop. > > if (W_flag++) > { > /* AI == Artificial Intimidation */ > printf("Don't type the W flag twice again. Or else...\n"); > exit(rand()); > } It's often more useful to have each use be a toggle (W_flag = !W_flag). The default value of the flag can then be reversed by use of an alias or an environment variable without locking the user into that default choice. ------------------------------------------------------------------------------ Oliver Steele ...!{decvax,ihnp4}!mcnc!unc!steele steele%unc@mcnc.org "They're directly beneath us, Moriarty. Release the piano!"