#43867 [Opn->Bgs]: Invalid round() function output

ID: 43867 Updated by: jani@php.net Reported By: pjotrik at post dot cz -Status: Open +Status: Bogus Bug Type: *Math Functions Operating System: Windows XP SP2 PHP Version: 5.2.5 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: ------------------------------------------------------------------------ [2008-01-16 15:46:00] pjotrik at post dot cz Sorry, I have a better example: echo (4.3*((100-25)/100)); ----> result: 3.225 echo round(4.3*((100-25)/100),2); ----> result: 3.22 echo round(3.225,2); ----> result: 3.23 ------------------------------------------------------------------------ [2008-01-16 15:13:49] pjotrik at post dot cz Description: ------------ When I try to round a number like X.YZ5 with precision 2, I get X.YZ, but Z number should be incremented to Z+1 Reproduce code: --------------- $a=round(2.225,2); Expected result: ---------------- $a=2.23 Actual result: -------------- $a=2.22 ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=43867&edit=1