#36008 [Opn->Fbk]: incorrect round() & number_format() result

ID: 36008 Updated by: iliaa@php.net Reported By: adi at rogers dot com -Status: Open +Status: Feedback Bug Type: Math related Operating System: win32 only PHP Version: 5CVS-2006-06-14 New Comment: 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 Previous Comments: ------------------------------------------------------------------------ [2006-10-31 00:39:37] adi at rogers dot com Aww well it's too late for me to bug it for Windows Vista as we've entered Release Candidate 2 :( I'll test this again on IIS7 with the final version of Vista... ------------------------------------------------------------------------ [2006-10-30 13:30:58] dave at koales dot co dot uk 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! ------------------------------------------------------------------------ [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]. ------------------------------------------------------------------------ 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