Article View: comp.lang.misc
Article #889Re: do...while vs. repeat...until (was: Errors aren't that simple)
From: C.E. Thompson
Date: Fri, 16 Mar 1990 15:42
Date: Fri, 16 Mar 1990 15:42
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In article <16188@haddock.ima.isc.com> karl@haddock.ima.isc.com (Karl Heuer) writes:
>In article <5819.25f7a840@vax1.tcd.ie> cbuckley@vax1.tcd.ie writes:
>>In article <Mar.7.10.43.42.1990.17402@paul.rutgers.edu>, emuleomo@paul.rutgers.edu (Emuleomo) writes:
>>> The other less serious flaw in C is the do...while contruct.
>>> I kind of prefer PASCAL's repeat....until construct myself.
>>
>>How can this be a flaw? The two constructs are identical except for the fact
>>that the condition is reversed...
>
>That's enough to make it a (minor) flaw. Judging from my own personal
>experience, it is more natural for a test-at-top loop to specify the condition
>for continuing (while), but for a test-at-bottom loop to specify the condition
>for terminating (until). I don't know if there's been a study on this; in
>fact, I'm not entirely sure how to formalize the concept.
Time for another BCPL-was(is)-better-than-C plug. BCPL has
WHILE expression DO command
UNTIL expression DO command
command REPEATWHILE expression
command REPEATUNTIL expression
and of course
command REPEAT /* for ever */
But you probably wanted to use some of those reserved words as variable
names, right? :-)
Chris Thompson
JANET: cet1@uk.ac.cam.phx
Internet: cet1%phx.cam.ac.uk@nsfnet-relay.ac.uk
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!mailrus!uunet!mcsun!ukc!cam-cl!cet1 From: cet1@cl.cam.ac.uk (C.E. Thompson) Newsgroups: comp.lang.misc Subject: Re: do...while vs. repeat...until (was: Errors aren't that simple) Message-ID: <1808@gannet.cl.cam.ac.uk> Date: 16 Mar 90 15:42:35 GMT References: <8192@hubcap.clemson.edu> <17000003@hpcvra.CV.HP.COM> <Mar.7.10.43.42.1990.17402@paul.rutgers.edu> <5819.25f7a840@vax1.tcd.ie> <16188@haddock.ima.isc.com> Sender: news@cl.cam.ac.uk Reply-To: cet1@cl.cam.ac.uk (C.E. Thompson) Organization: U of Cambridge Comp Lab, UK Lines: 32