From:	Erik Max Francis <max AT alcyone DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Problems with DJGPP V2.01 - atof() function
Date:	Sat, 30 Nov 1996 20:37:12 -0800
Organization:	Alcyone Systems
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Message-ID:	<32A10B78.742AEEA5@alcyone.com>
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Morten Welinder wrote:

> Getting 112 is well within the C standard.  If your program does
> not work in this situation then you have a bug.

The original response seems to be accurate.  atof("1.13")*100 gives you
112.9..., which a printf call will nicely round to 1.13 for you.  However,
it is still less than 113 -- casting it to an int will round down, giving
you 112.  Unfortunate, but a limitation of floating point calculations.

I just checked this on my Pentium Pro 200 which runs gcc 2.7.2 under Linux,
and got the same result.

> Floating point numbers are not exactly represented; you will see
> rounding errors.

That's the problem exactly.

-- 
                             Erik Max Francis | max AT alcyone DOT com
                              Alcyone Systems | http://www.alcyone.com/max/
                         San Jose, California | 37 20 07 N 121 53 38 W
                                 &tSftDotIotE | R^4: the 4th R is respect
         "But since when can wounded eyes see | If we weren't who we were"

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