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Bug #42803 Bad floor and int for float numbers
Submitted: 2007-09-30 19:49 UTC Modified: 2007-09-30 20:48 UTC
From: lacko at spacesystems dot sk Assigned:
Status: Not a bug Package: Unknown/Other Function
PHP Version: 5.2.4 OS: Windows XP
Private report: No CVE-ID: None
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 [2007-09-30 19:49 UTC] lacko at spacesystems dot sk 
Description:
------------
Hi,
I have problem with float numbers, when I try
$number = 40;
$number = (float)$number; // (number is float)
echo floor($number); // Output is 39

Why?

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 [2007-09-30 20:48 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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