#37683 [Opn->Bgs]: Comparison operator fails with certain numbers

ID: 37683 Updated by: mike@php.net Reported By: jeb at webco dot tv -Status: Open +Status: Bogus Bug Type: Math related Operating System: Linux / Ubuntu or Fedora PHP Version: 5.1.4 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: ------------------------------------------------------------------------ [2006-06-02 17:46:42] jeb at webco dot tv Description: ------------ Code 1 listed below does not work as expected. Code 2 does. Interesting bug. If I replace the "<= 0.01" with "< 0.02", it does work as expected. Reproduce code: --------------- Code 1: $data['low'] = 0.04; $data['high'] = 0.05; if ($data['high'] - $data['low'] <= 0.01) print "it works"; Code 2: $data['low'] = 0.02; $data['high'] = 0.03; if ($data['high'] - $data['low'] <= 0.01) print "it works"; Expected result: ---------------- Both instances should print "it works." Actual result: -------------- Code 1 prints nothing. Code 2 prints "it works". ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=37683&edit=1