ID: 35275
User updated by: uwe dot voelker at vline dot de
Reported By: uwe dot voelker at vline dot de
Status: Bogus
Bug Type: Math related
Operating System: Win XP
PHP Version: 5.0.5
New Comment:
OK, after reading ten pages about float i take
the ROUND function, it works now.
if ( (-56.33) != Round((-14.13) + (-42.20),2) ) {
print "<HR> First Example: Why is -56.33 not -56.33 ??? <HR>";
}
else
{
print "<HR> First Example: OK <HR>";
}
Previous Comments:
------------------------------------------------------------------------
[2005-11-18 14:59:52] [EMAIL PROTECTED]
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.
.
------------------------------------------------------------------------
[2005-11-18 14:13:33] uwe dot voelker at vline dot de
Description:
------------
Addition of some negative floats fails !
Reproduce code:
---------------
<?php
// PHP 5.05
// First example shows the bug
if ( (-56.33) != ((-14.13) + (-42.20)) ) {
print "<HR> First Example: Why is -56.33 not -56.33 ??? <HR>";
}
else
{
print "<HR> First Example: OK <HR>";
}
// Second example with modified values but same result is ok
if ( (-56.33) != ((-14.12) + (-42.21)) ) {
print "<HR> Second Example: Why is -56.33 not -56.33 ??? <HR>";
}
else
{
print "<HR> Second Example: OK <HR>";
}
?>
Expected result:
----------------
First example: true, but must be false.
Second example: false, it is OK.
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=35275&edit=1
