#34246 [Opn->Bgs]: Dividing number by half over and over eventually returns 0

ID: 34246 Updated by: derick@php.net Reported By: platinumsupreme at aol dot com -Status: Open +Status: Bogus Bug Type: Math related Operating System: Windows XP PHP Version: 4.4.0 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: ------------------------------------------------------------------------ [2005-08-25 11:41:23] platinumsupreme at aol dot com Description: ------------ There is a problem out there that states that if you take a number and keep dividing it by half you should never reach zero. But apparently in PHP that is not the case.. Reproduce code: --------------- <?php $number = 50; echo "Starting Number: $number<br>"; while($number > 0){ $number = $number / 2; echo "Number: $number<br>"; } ?> Expected result: ---------------- It should just go on for a ridiculous amount of time until it memory leaks... Actual result: -------------- It ends up at 0. ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=34246&edit=1