Bug #77425 [Nab]: Operator error
| From: | peehaa@php.net | Date: | Mon, 07 Jan 2019 17:07:37 +0000 |
| Subject: | Bug #77425 [Nab]: Operator error | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-218836@lists.php.net to get a copy of this message | ||
Edit report at https://bugs.php.net/bug.php?id=77425&edit=1
ID: 77425
Updated by: peehaa@php.net
Reported by: karolyizoltan dot 1 at gmail dot com
Summary: Operator error
Status: Not a bug
Type: Bug
Package: Math related
Operating System: Windows 8.1
PHP Version: 7.1.25
Block user comment: N
Private report: N
New Comment:
To expend on the above please read the hard to miss big red warning on the Floating point numbers
documentation page:
http://php.net/manual/en/language.types.float.php
Previous Comments:
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[2019-01-07 17:04:00] requinix@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.
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.
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[2019-01-07 16:56:52] karolyizoltan dot 1 at gmail dot com
Description:
------------
SYSTEM
I test here by PHP 7.2.4 as well: http://sandbox.onlinephpfunctions.com/
and on my desktop 7.1.25 (this come from the php is downloaded and installed from here: https://www.apachefriends.org/download.html)
PROBLEM
The same values in case of some operators do not result the right outcomes. All of the six cases
need to be true but first four return false values.
Test script:
---------------
$a = '0.9';
$b = '7.34';
$c = '100';
$d = floor(($a * $b)*100)/100;
$e = $c + $b - $d;//this return 100.74 too
$f = 100.74;
// values of variables
var_dump($e);
var_dump($f);
//first four return false values but all of them need to be true
var_dump($e == $f);//false
var_dump($e <= $f);//false
var_dump($f >= $e);//false
var_dump($e == $f);//false
var_dump($e >= $f);//true
var_dump($f <= $e);//true
Expected result:
----------------
All the equations need to return true value for the same numbers.
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Edit this bug report at https://bugs.php.net/bug.php?id=77425&edit=1