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Bug #30330 fmod() does not return the correct value.
Submitted: 2004-10-05 19:46 UTC Modified: 2004-10-05 20:40 UTC
From: dbauleo at terra dot com dot br Assigned:
Status: Not a bug Package: Math related
PHP Version: 4.3.9 OS: Windows 2000
Private report: No CVE-ID: None
 [2004-10-05 19:46 UTC] dbauleo at terra dot com dot br
Description:
------------
I used the fmod() function with float numbers, and it was an exact division, so it was supposed to return 0, instead of it, the Y value was returned.

Reproduce code:
---------------
<?php

  echo fmod(396456.06, 56636.58);

?>

Expected result:
----------------
fmod(396456.06, 56636.58) = 0

Actual result:
--------------
fmod(396456.06, 56636.58) = 56636.58

function f_mod($x,$y)
{
$i = floor($x / $y);
$a = $x - $i * $y;
return $a;
}

f_mod(396456.06, 56636.58) = 0

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History

AllCommentsChangesGit/SVN commitsRelated reports
 [2004-10-05 20:40 UTC] derick@php.net
Floating point values have a limited precision. Hence a value might 
not have the same string representation after any processing. That also
includes writing a floating point value in your script and directly 
printing it without any mathematical operations.
 
Thank you for your interest in PHP.

.
 
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