From: Endlisnis <s257m AT unb DOT ca>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: LARGE numbers.
Date: Fri, 28 Aug 1998 11:07:25 -0300
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Kevin Ashley wrote:
> >> double dvar;
> >>         dvar = 25834242042;
> >    This line WILL work, I've already uploaded example code that shows this working.
> 
> I hadn't seen your example when I posted. However, I think there is
> still some room for both to be correct. Your example was C++; I don't
> program in that, but use C exclusively. I'm familiar with the C standard
> but not with C++.  As far as C is concerned, that constant is an integer
> constant, which is then effectively cast to a double at compilation time.
> If it's too big to fit in an int, the results are undefined.

	It'll work in C as well:

#include <stdio.h>

int main()
{
 double Double = 25834242042;
 printf("%15f\n", Double);
 }

Output:
25834242042.000000


> GCC produces warnings at compilation time that the constant is too big
> for an integer, and that it will end up being unsigned. I suspect it
> must internally store the evaluation in a long long int, since it
> does produce correct results despite the warnings, but this is definitely
> compiler-specific behaviour and cannot be relied upon in general. I've
> tried it on another compiler (ANSI-compatible but not GCC) and both
> the double and the int end up equal to 64438266 (with a similar slew
> of warnings.)
> 
> So, it may work, but if the target language is C it isn't right and
> it isn't portable and sooner or later it may cause you problems. If
> we're talking C++, I confess ignorance.
	Well, if people are mentioning compiler specific stuff like 'long long', then
I thought it would be ok if I mentioned that you could initialized a double
with a literal int.  Even if it isn't portable.
-- 
     (\/) Endlisnis (\/)
          s257m AT unb DOT ca
          Endlisnis AT GeoCities DOT com
          Endlis AT nbnet DOT nb DOT ca