note 63619 added to language.types.float

Re: rick at ninjafoo dot com There is no need to “always” use the BCMath functions. We just need to heed the documentation and “never compare floating point numbers for equality”. The reason (19.6*100) !== (double)1960, is because inside a computer they are not equal. Try this: <?php printf("%.15f", (19.6*100)); ?> Outputs: 1960.000000000000227 (not 1960 as somewhat expected) If comparison is required a few options come to mind (other than BCMath): 1) Round numbers before comparison: <?php $sig_figs = 5; echo (round((19.6*100), $sig_figs) !== round((double)1960, $sig_figs)) ? 'not equal' : 'equal'; ?> Outputs: equal 2) Another method is to use a tolerance value, and consider numbers equal if their difference is less than the tolerance. ---- Server IP: 66.163.161.117 Probable Submitter: 69.195.8.22 ---- X-Spam-Status: No, hits=3.1 required=5.0 tests=DATE_MISSING,FROM_NO_LOWER autolearn=no version=2.64 ---- Manual Page -- http://www.php.net/manual/en/language.types.float.php Edit -- http://master.php.net/note/edit/63619 Del: integrated -- http://master.php.net/note/delete/63619/integrated Del: useless -- http://master.php.net/note/delete/63619/useless Del: bad code -- http://master.php.net/note/delete/63619/bad+code Del: spam -- http://master.php.net/note/delete/63619/spam Del: non-english -- http://master.php.net/note/delete/63619/non-english Del: in docs -- http://master.php.net/note/delete/63619/in+docs Del: other reasons-- http://master.php.net/note/delete/63619 Reject -- http://master.php.net/note/reject/63619 Search -- http://master.php.net/manage/user-notes.php