#34539 [Bgs->Opn]: tqjs

ID: 34539 User updated by: roy dot name at gmail dot com Reported By: roy dot name at gmail dot com -Status: Bogus +Status: Open Bug Type: Unknown/Other Function Operating System: windows PHP Version: 5.1.0RC1 New Comment: <?php $test = 12.4; if ( $test*3 == 37.2 ) { echo 'True'; } else { echo 'False'; # This is the out? } ?> If I change the Floating point values,for example:12.4,then,the result is 37.2,and it can output the actual result Previous Comments: ------------------------------------------------------------------------ [2005-09-18 06:25:34] alan_k@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://docs.sun.com/source/806-3568/ncg_goldberg.html Thank you for your interest in PHP. - ------------------------------------------------------------------------ [2005-09-18 05:44:37] roy dot name at gmail dot com Description: ------------ Why the (9.8*3 != 29.4) see the code may know clear Reproduce code: --------------- <?php $test = 9.8; if ( $test*3 == 29.4 ) { echo 'True'; } else { echo 'False'; # This is the out? } # If the value of $test is many others value ,and '29.4' is # the correct value,the program will out the True; ?> Expected result: ---------------- Expected result:True Actual result: -------------- Actual result: False ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=34539&edit=1