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From: bill@cafe.net (Kaz Kylheku)
Subject: Re: Which language pays most? Smalltalk, not C++ nor Java.
Date: 1997/12/30
Message-ID: <68bu22$geg$1@brie.direct.ca>#1/1
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References: <199712121931.LAA25389@sirius.infonex.com>
 <685mee$5d4$1@sparcserver.lrz-muenchen.de> <34A812F9.C169A703@its.cl>
 <Pine.A41.3.95.971230143114.19568A-100000@acis.mc.yu.edu>
Organization: Internet Direct
Reply-To: kaz@cafe.net
Newsgroups: 
 comp.lang.fortran,comp.lang.c,comp.lang.c++,comp.lang.eiffel,comp.lang.java.programmer,comp.lang.smalltalk,comp.lang.perl.misc,comp.lang.ada,comp.edu
Date: 1997-12-30T00:00:00+00:00
List-Id: <comp.lang.ada>


In article <Pine.A41.3.95.971230143114.19568A-100000@acis.mc.yu.edu>,
Joshua Waxman  <jwaxman@ymail.yu.edu> wrote:
>> In C++ there is no way to handle overflow of integers.
>
>Check after each addition to see if you reversed signs, and act
>accordingly.

That is absurd. Overflow invokes undefined behavior in C++. To check
for sign reversal, you would have to depend on a particular platform's
handling of overflow. On two's complement systems, overflow on addition or
subtraction can be detected by examining the most significant bit of the
result and those of the operands. This isn't true in general, however.

It's possible to determine whether a given operation will occur by
writing a test expression (or assertion) which itself does not invoke
overflow.