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From: Matthew Heaney <matthew_heaney@acm.org>
Subject: Re: Software landmines (loops)
Date: 1998/09/01
Message-ID: <m3n28kq2jn.fsf@mheaney.ni.net>#1/1
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NNTP-Posting-Date: Mon, 31 Aug 1998 21:06:30 PDT
Newsgroups: comp.lang.eiffel,comp.object,comp.software-eng,comp.lang.ada
Date: 1998-09-01T00:00:00+00:00
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"Robert Martin" <rmartin@oma.com> writes:

> >One entry, one exit. Perfectly clear. There's nothing magic about
> >putting the exit statement at the top or the bottom!
> 
> In fact there is.  If the exit condition is at the top or the bottom, then
> the body of the loop will always be excuted an exact integral number of
> times.  However if the loop condition is in the middle, then the loop body
> will be executed a fractional number of times.

I think we're losing site of the forest through the trees.  The
important thing is the postcondition for the loop.  Is the postcondition
satisfied or not?

If the postcondition is satisfied, then what difference does the number
of iterations (fractional or otherwise) make?

Our goal is NOT "execute the loop body an integral number of times."
Our goal IS to satisfy the loop postcondition, in the simplest way
possible.