ID: 36008
Comment by: dave at koales dot co dot uk
Reported By: adi at rogers dot com
Status: Open
Bug Type: Math related
Operating System: win32 only
PHP Version: 5CVS-2006-06-14
New Comment:
I think this is a Windows vs others thing. I have the same rounding
error using PHP 5.0.5 on Windows XP SP2.
The same problem does not exist on my webhost, who use PHP 4.3.9 and
Redhat Linux (need any more detail).
The code I used was:
echo "Correct VAT = " . round( 0.525, 2 ) . "\r\n";
echo "Wrong VAT = " . round( 3 * ( 17.5 / 100.0 ), 2 ) . "\r\n";
Outputs 0.53 for each on webhost (under Linux) and 0.52 for the second
test under Windows (0.53 for the first test).
I've also had very bizarre rounding errors with MySQL. The rounding
error came and went depending on how the calculation was constructed!
Previous Comments:
------------------------------------------------------------------------
[2006-10-10 21:44:21] adi at rogers dot com
Amen to that ;)
------------------------------------------------------------------------
[2006-10-10 07:45:36] troy20 at mail dot ru
Code:
for ($i = 1.075;$i <= 1.975;$i=$i+0.1)
{echo round($i,2);}
Result:
1.08, 1.18, 1.28, 1.38....
But if
echo round(1.275,2);
echo round(1.275*100);
we have 1.27 and 127.
Another "same" example:
for ($i = 1.075;$i <= 20.975;$i=$i+0.1)
{echo round($i,2);}
Win2003 + Apache 2.0.59 + php 5.1.6
------------------------------------------------------------------------
[2006-06-14 22:11:53] adi at rogers dot com
Regretfully, the same output:
5.2.0-dev
Wrong: 14.37
Wrong: 14.37
'Magically' correct: 14.38
'Magically' correct: 14.38
Converted to string and is now correct: 14.38
Converted to string and is now correct: 14.38
The 32 precision results are also the same [as the ones on January 15].
------------------------------------------------------------------------
[2006-06-14 15:50:08] [EMAIL PROTECTED]
Please try using this CVS snapshot:
http://snaps.php.net/php5.2-latest.tar.gz
For Windows:
http://snaps.php.net/win32/php5.2-win32-latest.zip
------------------------------------------------------------------------
[2006-01-15 06:40:25] adi at rogers dot com
Oh, and as I had suspected, here is the value of $num with 32
precision: 14.374999999999998
With 12 as the precision, it is: 14.375
------------------------------------------------------------------------
The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at
http://bugs.php.net/36008
--
Edit this bug report at http://bugs.php.net/?id=36008&edit=1
