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Bug #54164 Wrong Output Values
Submitted: 2011-03-04 23:17 UTC Modified: 2011-03-04 23:33 UTC
From: eskolife at hotmail dot com Assigned:
Status: Not a bug Package: *General Issues
PHP Version: 5.3.5 OS: Windows XP SP3
Private report: No CVE-ID: None
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 [2011-03-04 23:17 UTC] eskolife at hotmail dot com 
Description:
------------
$Val = cos(deg2rad(60));
$Val = $Val * 10;
echo $Val.'---'.intval($Val).'<br>';
echo $Val.'---'.floor($Val);

then the output of this simple code should be:
5---5
5---5

but the real output is:
5---4
5---4


Test script:
---------------
<?php

  $Val = cos(deg2rad(60)); 
  $Val = $Val * 10;
  echo $Val.'---'.intval($Val).'<br>';
  echo $Val.'---'.floor($Val);

?>

Expected result:
----------------
5---5
5---5

Actual result:
--------------
5---4
5---4

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 [2011-03-04 23:33 UTC] rasmus@php.net
-Status: Open +Status: Bogus
 [2011-03-04 23:33 UTC] rasmus@php.net 
Truncating floating point values is always dangerous because computers do not 
store floating point values precisely, so when you do floor(4.999999999999999) you 
are going to get 4, not 5. Use round() instead. You can read more about it here: 
http://en.wikipedia.org/wiki/IEEE_754-2008
 
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