ID: 50398 Updated by: johan...@php.net Reported By: blanca at netvision dot net dot il -Status: Open +Status: Bogus Bug Type: Unknown/Other Function Operating System: windows xp PHP Version: 5.3.1 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. The docs say "When converting from float to integer, the number will be rounded towards zero." http://php.net/manual/en/language.types.integer.php#language.types.integer.casting Now combining this with the unprecise nature of floating point numbers this gives "random" results. Previous Comments: ------------------------------------------------------------------------ [2009-12-07 12:40:31] blanca at netvision dot net dot il Description: ------------ when converting 12.999999999999999 from float to int, the output is 12 but, when converting 12.9999999999999999 from float to int, the output is 13 Reproduce code: --------------- $a=12.9999999999999999; $b=(int)$a; $a=12.999999999999999; $c=(int)$a; $str="\$b is: ".$b." and \$c is: ".$c; echo $str; Expected result: ---------------- $b is: 12 and $c is: 12 Actual result: -------------- $b is: 13 and $c is: 12 ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=50398&edit=1
