php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login

go to bug id or search bugs for

Bug #61624 round
Submitted: 2012-04-04 17:06 UTC Modified: 2012-04-05 13:49 UTC
From: gufophp at gmail dot com Assigned:
Status: Not a bug Package: Math related
PHP Version: 5.4.0 OS: win32
Private report: No CVE-ID: None
View Developer Edit
Welcome back! If you're the original bug submitter, here's where you can edit the bug or add additional notes.
If you forgot your password, you can retrieve your password here.
Password:
Status:
Package:
Bug Type:
Summary:
From: gufophp at gmail dot com
New email:
PHP Version: OS:

 

 [2012-04-04 17:06 UTC] gufophp at gmail dot com 
Description:
------------
<?php
echo round(33.29999999999999715783,4);  // fail
echo "-";
echo round(33.29999999999999715783,2); // fail
echo "-";
echo round(33.29999999999999715783);  //ok
echo "-";
echo round(33.29999999999999715783,-1); //ok
echo "-";
echo round(55533.29999999999999715783,-2); //ok
?>

Test script:
---------------
33.29999999999999715783-33.29999999999999715783-33-30-55500

Expected result:
----------------
33.3-33.3-33-30-55500

Actual result:
--------------
33.29999999999999715783-33.29999999999999715783-33-30-55500

Patches

Pull Requests

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2012-04-05 03:05 UTC] reeze dot xia at gmail dot com 
Hi, gufophp:
  I can't reproduce it in both 5.4 & 5.3 | Win7 & Mac OS X. can you feedback more 
information about this?.

Thanks
 [2012-04-05 13:08 UTC] gufophp at gmail dot com 
php.ini
change precision to
precision = 17
 [2012-04-05 13:49 UTC] aharvey@php.net
-Status: Open +Status: Not a bug
 [2012-04-05 13:49 UTC] aharvey@php.net 
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://www.floating-point-gui.de/

Thank you for your interest in PHP.

The return value of round() is still a floating point number. If the precision is 
high enough, printing that float may result in seeing additional significant 
digits because of the imprecision inherent to floating point arithmetic.
 
PHP Copyright © 2001-2024 The PHP Group
All rights reserved. 		Last updated: Fri Dec 27 04:01:29 2024 UTC