Bug #54414 [Opn->Bgs]: Floating-Point Arithmetic Bug

From: Date: Mon, 28 Mar 2011 19:32:12 +0000
Subject: Bug #54414 [Opn->Bgs]: Floating-Point Arithmetic Bug
References: 1  Groups: php.bugs 
Request: Send a blank email to php-bugs+get-159820@lists.php.net to get a copy of this message 
Edit report at http://bugs.php.net/bug.php?id=54414&edit=1

 ID:                 54414
 Updated by:         dtajchreber@php.net
 Reported by:        ejsexton82 at gmail dot com
 Summary:            Floating-Point Arithmetic Bug
-Status:             Open
+Status:             Bogus
 Type:               Bug
 Package:            Math related
 Operating System:   Windows Server 2003
 PHP Version:        5.3.6
 Block user comment: N
 Private report:     N

 New Comment:

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.

If you would like to know more about "floats" and what IEEE
754 is, read this:
http://www.floating-point-gui.de/

Thank you for your interest in PHP.




Previous Comments:
------------------------------------------------------------------------
[2011-03-28 20:57:06] ejsexton82 at gmail dot com

Description:
------------
The following calculation yields an unexpected result.

Test script:
---------------
$test = 625.0 - 661.7 + 37.0;
var_dump($test);

Expected result:
----------------
0.3

Actual result:
--------------
0.29999999999995


------------------------------------------------------------------------



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Edit this bug report at http://bugs.php.net/bug.php?id=54414&edit=1

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