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Re: atof returns a value that is slightly greater than the original string
- To: Marco Craveiro <soupdragon at clix dot pt>
- Subject: Re: atof returns a value that is slightly greater than the original string
- From: Andrew Markebo <flognat at flognat dot myip dot org>
- Date: 10 Sep 2001 22:52:47 +0200
- Cc: cygwin at cygwin dot com
- References: <1000153353.1101.8.camel@darkroom>
/ Marco Craveiro <soupdragon@clix.pt> wrote:
| Hello Cygwinners,
|
| I'm having some strange problems with atof. basically, it returns a
| converted value that is 0.000024 bigger than the one on the string.
|
| Google searching suggested that the problem was to do with #include
| <stdlib.h>, but I already have that #include in my program and I still
| get strange results. A program like this:
|
Same problem here if I do:
#include <cstdlib>
#include <iostream>
int main (void)
{
float f=695.40;
cout << f;
}
my gdb says f is 695.400024
If my mind doesn't fail me completely this is a 'misfeature' in float,
the way that the data is stored in can't be exact.. or something..
The recommendations I have seen was to use some alternative
bignum/smallnum package :-) Or if you know how many decimals you can
get, multiply the value by that amount.. and convert to int.
The reason to why you don't see it on cout is that cout prints floats
with 1 or two decimals per default, if you tell it to print.. MANY
decimals..
/Andy
--
The eye of the beholder rests on the beauty!
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