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From: John Potter <jpotter@falcon.lhup.edu>
Newsgroups: comp.lang.ada,comp.lang.c++.moderated
Subject: Re: C bug of the day
Date: 16 Jun 2003 05:06:40 -0400
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On 15 Jun 2003 17:55:12 -0400, Francis Glassborow
<francis.glassborow@ntlworld.com> wrote:

 > In message <u8enev0gr0rmbq7p4l3gh4sa5f80ohu43e@4ax.com>, John Potter
 > <jpotter@falcon.lhup.edu> writes
 > >> int i(read<int>(stream));

 > >Let's see your template.  My guess:

 > >template <class T>
 > >T read (istream& is) {
 > >   T item; // uninitialized or default constructed
 > >   is >> item;
 > >   return item;
 > >   }

 > >I'm guessing that you are just hiding the uninitialized fundamental or
 > >default constructing a udt.

 > Come on, I can write better code than that. The main point was that
 > input should be at least validated as appropriate to the type,.

Your article was in the part of the thread talking about uninitialized
variables.  You claimed that any decent programmer had a way around
that.  The first line is all that counts and it matches your posted
code.  The template does not solve the problem no matter how much
error testing you add.  You still have a desirable uninitialized
fundamental and can not avoid default construction of udt.  It is
possible to avoid the problem for udt with a constructor taking a
stream; however, that does not generalize to a universal template.

Not a question of the quality of your code.  Just a guess that it had
nothing to do with the subject.  QED.

John

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