From:	"Rob McCrea" <r_mccrea AT hotmail DOT com>
Newsgroups:	comp.os.msdos.djgpp
References:	<dhwa4.274$Gh2 DOT 1735 AT newsfeed DOT slurp DOT net>
Subject:	Re: oh, + casts to int?
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Date:	Wed, 29 Dec 1999 18:49:08 -0500
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To:	djgpp AT delorie DOT com
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Reply-To:	djgpp AT delorie DOT com

Stroustrup, tc++pl pp. 122: "operands smaller than int are converted
to int before the operator is allied"

while ((s+1) > s) s++; //not right.
while ((static_cast<short>(s+1)) > s) s++; //is right for short s.

Well, thanks for listening I'm still a little curious why some
compilers needed the cast and some don't.


"Rob McCrea" <r_mccrea AT hotmail DOT com> wrote in message
news:dhwa4.274$Gh2 DOT 1735 AT newsfeed DOT slurp DOT net...
> My expression won't recognize the overflow...
>
> while ((s+1) > s) s++;
>
> is an infinite loop.  What's up with that?
> Apparently the condition is being evaluted as (1>0).
> That's not right is it?  I'm compiling with gpp -Wall
testsize.cpp -o
> testsize.exe.
>
> Please, can someone explain why its not acting like a computer?
>
> On the subject that led me on the above side-trip, I need a library
> that will allow me to use much larger (non-float and unsigned)
> integers.  unsigned long long fails at 2^64 of course.  I will want
to
> calculate up to 2^10000000 for starters, but anything that will
allow
> greater than 2^64 is an improvement (I'm hoping to find a type that
> would only be limited by the amount of freespace on your hardrive).
> Any base will work.  I need multiplication (or exponential),
division
> (or modulo), and subtraction.  If you know of one, please reply.
>
> Rob.
>
> ////testsize.cpp////
> #include <iostream>
>
> int main()
> {
>     short s=0;
>     while ((s+1) > s)
>     {
>         s++;
>         cout << s << endl;
>     }
>     cout << "max:  " << s << endl;
>     return 0;
> }
> ////end source////
>
>

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