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Bug #34442 Incorrect numerical result produced
Submitted: 2005-09-09 18:22 UTC Modified: 2005-09-09 18:38 UTC
From: thirteenlisk at gmail dot com Assigned:
Status: Not a bug Package: *General Issues
PHP Version: 5.0.5 OS: Windows XP
Private report: No CVE-ID: None
 [2005-09-09 18:22 UTC] thirteenlisk at gmail dot com
Description:
------------
Using intval() with some numbers produces an incorrect value.

This applies these two specific values: 10.2 and 20.4. (Each is off by one.)

Reproduce code:
---------------
echo intval(100 * 10.2);

Expected result:
----------------
1020

Actual result:
--------------
1019

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 [2005-09-09 18:38 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.

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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