#47208 [Opn->Bgs]: Converting Float/Double to Integer bug.
ID: 47208
Updated by: mattwil@php.net
Reported By: superdude at hotmail dot com
-Status: Open
+Status: Bogus
Bug Type: Math related
Operating System: win32/64 possibly others.
PHP Version: 5.2.8
New Comment:
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.
1.003 is stored as slightly less than that (close as possible), which
can be seen when you show enough digits:
printf('%.20f', 1.003);
Gives 1.00299999999999989164 for me...
Previous Comments:
------------------------------------------------------------------------
[2009-01-24 13:44:22] superdude at hotmail dot com
Description:
------------
When multiplying a float/double that the has value of 1.003, converting
it to a integer, will always return the expected value, minus 1.
Reproduce code:
---------------
<?php
$x = 1.003;
echo (int)($x*1000)."<br>\n";
echo (int)($x*10000)."<br>\n";
echo (int)($x*100000)."<br>\n";
?>
Expected result:
----------------
1003
10030
100300
Actual result:
--------------
1002
10029
100299
------------------------------------------------------------------------
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Edit this bug report at http://bugs.php.net/?id=47208&edit=1
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