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From: David Hanley <david@netright.com>
Subject: Re: OO, C++, and something much better!
Date: 1997/01/29
Message-ID: <32EFA614.7C93@netright.com>#1/1
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references: <dewar.854327202@merv> <32edc09c.3000098@nntp.interaccess.com>
 <dewar.854542049@merv> <5cnii3$r9q$1@news.nyu.edu>
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 comp.object,comp.lang.c++,comp.lang.ada,comp.lang.smalltalk,comp.lang.eiffel
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Date: 1997-01-29T00:00:00+00:00
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Richard Kenner wrote:
> 
> In article <dewar.854542049@merv> dewar@merv.cs.nyu.edu (Robert Dewar) writes:
> >I once had someone (who shall be nameless) working on the Ada Ed project
> >who said to me "there is no point in worrying about being one off in a loop,
> >you will find the error during testing anyway". Needless to say, this person
> >did not work long on the project! It is this kind of attutide that brings
> >you many of the high profile software screwups in this world!
> 
> I think you've given a bad example.  Off-by-one in a loop is often a
> situation where it will either not work at all or work correctly.

#define NumEntries 100000
entry entries[ NumEntrues ];

for( a = 0 ; a < min( top , NumEntries ) ; ++ a ) 
{
    ....
}

It seems very likely to me that the above may get missed in testing. 


> I agree that a programmer who cannot *do* the analysis or who doesn't
> understand why one might want to do that is not somebody I'd want to
> hire, but I don't see what's wrong with deciding that it's faster to
> take experimental approach and try both ways than to spend the time
> convincing oneself exactly which is correct.  Of course, if the
> decision isn't framed in precisely that way, I agree with you.

	I think that this discussion( dynamic vs static typing ) could be more
broadly generalized to a discussion of weather it is better to find bugs
by testing, or to find bugs by formal mentods( types, constraints, etc
).


-- 
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David Hanley, Software Developer, NetRight technologies.
My employer pays me for my opinions; nonetheless he does not share all
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