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Bug #43976 Problem with float
Submitted: 2008-01-29 21:39 UTC Modified: 2008-01-29 22:59 UTC
From: gh-ush at gmx dot de Assigned:
Status: Not a bug Package: Unknown/Other Function
PHP Version: 5.2.5 OS: Debian
Private report: No CVE-ID: None
View Developer Edit
 [2008-01-29 21:39 UTC] gh-ush at gmx dot de 
Description:
------------
Problem with float

Reproduce code:
---------------
$a = 74.1;
var_dump($a);
echo "<hr>";
$a = $a * 100;
var_dump($a);
print "<hr>";
$a = (int)$a;
var_dump($a);
print "<hr>";
exit;


Expected result:
----------------
float(74.1)
---------------------
float(7410)
---------------------
int(7409)

Actual result:
--------------
float(74.1)
---------------------
float(7410)
---------------------
int(7410)

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 [2008-01-29 22:59 UTC] johannes@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://docs.sun.com/source/806-3568/ncg_goldberg.html
 
Thank you for your interest in PHP.

.
 
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