ID: 35986 Updated by: [EMAIL PROTECTED] Reported By: nathan at pngwyn dot com -Status: Open +Status: Bogus Bug Type: *Math Functions Operating System: Linux PHP Version: 5.1.2 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. Previous Comments: ------------------------------------------------------------------------ [2006-01-12 22:37:48] nathan at pngwyn dot com Description: ------------ Rounding error on all numbers between 2048 and 8191 ending with .575 - When rounding to two decimal places. For Example, instead of rounding 2048.575 up to 2048.58 it is rounding down to 2048.57 See attached Code. Example URL: http://www.pngwyn.com/test.php * Note: Example URL is running 5.05 - But this has been tested on 5.1.2 as well. Reproduce code: --------------- <?php $start = 2040.575; $for = '6500'; $max = $for + $start; print("<font face=verdana size=2><a href=\"http://www.pngwyn.com/phpinfo.php\";>PHP Info for this Server</a><br><br>"); for($i = $start; $i <= $max; $i++) { $round = round($i, 2); print("Original Number: <b>$i</b> --- Rounded Number: <b>$round</b> <br>"); } ?> Expected result: ---------------- Original Number: 2046.575 --- Rounded Number: 2046.58 Original Number: 2047.575 --- Rounded Number: 2047.58 Original Number: 2048.575 --- Rounded Number: 2048.58 Original Number: 2049.575 --- Rounded Number: 2049.58 [ 2050.575 - 8189.575 ... ] Original Number: 8190.575 --- Rounded Number: 8190.58 Original Number: 8191.575 --- Rounded Number: 8191.58 Original Number: 8192.575 --- Rounded Number: 8192.58 Original Number: 8193.575 --- Rounded Number: 8193.58 Actual result: -------------- Original Number: 2046.575 --- Rounded Number: 2046.58 Original Number: 2047.575 --- Rounded Number: 2047.58 Original Number: 2048.575 --- Rounded Number: 2048.57 Original Number: 2049.575 --- Rounded Number: 2049.57 [ 2050.575 - 8189.575 ... ] Original Number: 8190.575 --- Rounded Number: 8190.57 Original Number: 8191.575 --- Rounded Number: 8191.57 Original Number: 8192.575 --- Rounded Number: 8192.58 Original Number: 8193.575 --- Rounded Number: 8193.58 ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=35986&edit=1
