From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=0.2 required=5.0 tests=BAYES_00,INVALID_MSGID, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: fac41,9a0ff0bffdf63657 X-Google-Attributes: gidfac41,public X-Google-Thread: f43e6,9a0ff0bffdf63657 X-Google-Attributes: gidf43e6,public X-Google-Thread: 1108a1,9a0ff0bffdf63657 X-Google-Attributes: gid1108a1,public X-Google-Thread: 103376,4b06f8f15f01a568 X-Google-Attributes: gid103376,public From: ell@access.digex.net (Ell) Subject: Re: Software landmines (loops) Date: 1998/10/03 Message-ID: <3626ce77.25791606@news.erols.com>#1/1 X-Deja-AN: 397296652 Content-Transfer-Encoding: 7bit References: <6rf59b$2ud$1@nnrp1.dejanews.com> <6rfra4$rul$1@nnrp1.dejanews.com> <35DBDD24.D003404D@calfp.co.uk> <6sbuod$fra$1@hirame.wwa.com> <35f51e53.48044143@news.erols.com> <6sdiav$e0g$1@hirame.wwa.com> <6sfcft$70p$1@hirame.wwa.com> <1dg8p3r.vfredh1aou58iN@n207167116191.inetworld.net> <6v2nr9$t8l$1@hirame.wwa.com> <6v39i0$fte$1@winter.news.erols.com> <6v4d5l$blb$1@hirame.wwa.com> Content-Type: text/plain; charset=us-ascii X-Complaints-To: abuse@rcn.com X-Trace: winter.news.erols.com 907400597 27122 207.172.44.224 (3 Oct 1998 07:43:17 GMT) Organization: Universe Mime-Version: 1.0 Reply-To: ell@access.digex.net Newsgroups: comp.lang.eiffel,comp.object,comp.software-eng,comp.lang.ada Date: 1998-10-03T00:00:00+00:00 List-Id: "Robert C. Martin" wrote: >John I. Moore, Jr. <70672.1744@compuserve.com> wrote in message >> >>Robert C. Martin wrote in message <6v2nr9$t8l$1@hirame.wwa.com>... >>> >>>The question that the post was addressing had to do with the definition of >>>structured programming. A mid exit loop does not fall within the bounds >>>defined by structured programming because the loop body does not then have >>> a single entry and a single exit. >>I'm sorry, Martin. I usually agree with your posts, but I will have to >>object to this one. Whose definition are you using for structured >>programming? Some of the earliest articles and books on structured >>programming were written by Harlan Mills of IBM, and he always >>defined a loop with a middle exit as an integral part of structured >>programming. He called it a do-while-do loop. >Yes, Mills did make this definition. However, I am referring to the work of >Dijkstra in the late 60's and early 70's. Dijkstra was very clear about the >notion of single entry and single exit within the body of a loop. I believe >that Mills' do-while-do loop is an unauthorized addition to Dijkstra's work. I hope you are not referring to the Dijkstra quotes on how to properly create flowcharts. And I hope you are not alleging that structured programming boils down to exiting from a loop. Another thing to remember is that while a procedure may return to its caller from multiple places the flow of control always returns to the same place in the caller. Either way, it was abstraction and not simple navigation which came to Dijkstra's mind when structured programming was mentioned. We holistic, pre-code modellers will always have that, I'm happy to say. Elliott -- :=***=: VOTE NO TO MODERATION! :=***=: CRAFTISM SHOULD NOT USE USENET RESOURCES TO AVOID CRITICISM! MODERATORS SHOULD NOT HAVE LIFETIME TERMS! :=***=: Objective * Pre-code Modelling * Holistic :=***=: Hallmarks of the best SW Engineering Study Phony Crafite OO vs. Genuine OO: http://www.access.digex.net/~ell Copyright 1998 Elliott. exclusive of others' writing. may be copied without permission only in the comp.* usenet and bitnet groups.