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From: Patrick Logan <plogan@user2.teleport.com>
Subject: Re: Software landmines (loops)
Date: 1998/10/05
Message-ID: <fRZR1.21268$K02.12603337@news.teleport.com>#1/1
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References: <6qfhri$gs7$1@nnrp1.dejanews.com> <u90k5f1j1.fsf@gsfc.nasa.gov>
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 <slrn71blhi.rle.behrends@allegro.cse.msu.edu>
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Organization: Teleport - Portland's Public Access (503) 220-1016
NNTP-Posting-Date: Sun, 04 Oct 1998 23:40:11 PDT
Newsgroups: comp.lang.eiffel,comp.object,comp.software-eng,comp.lang.ada
Date: 1998-10-05T00:00:00+00:00
List-Id: <comp.lang.ada>

In comp.object Reimer Behrends <behrends@cse.msu.edu> wrote:
: > 
: >                loop
: >                   <first part>
: >                   exit
: >                   <second part>
: >                end loop
: > 
: > Please point out the two exits...

: 		<first part>
: 		exit
: 		<second part>

: It has an exit at the "exit" statement, and one at the end of <second
: part>, where control flow leaves the body to reenter at the top.  And
: I'm not kidding you. Try to put the loop body into a procedure of its
: own, and this becomes very visible. (Ease of procedural decomposition is
: usually one of the benefits of strict single-entry, single-exit
: structures.)

Well, you can easily put this into *two* procedures and end up with a
"structured program"...

void first_part()
  {
    <first part>
    if (!condition)
       second_part();
  }

void second_part()
  {
    <second part>
    first_part();
  }

...maybe a measure of the degree of "structuredness" of a loop is *how
many* well structured procedures result from the conversion?

-- 
Patrick Logan    (H) mailto:plogan@teleport.com 
                 (W) mailto:patrickl@gemstone.com 
                 http://www.gemstone.com