#27744 [Com]: 141.23 - 141.00 = 0.22999999999999 ?

ID: 27744 Comment by: garbo_doe at hotmail dot com Reported By: t dot steve at ariadne-quatra dot com Status: Bogus Bug Type: Math related Operating System: * PHP Version: * New Comment: echo (string)(75000.00 - 74999.00); returns 1, not 0.9999999999. Is this a bug then? ;) "Guys, how in the world is PHP supposed to magically guess what precision you want results displayed in." Maybe a magicless solution would be: don't use greater precision then either the minuend or subtrahend (the one with greatest precision). Thanks for you answers and for PHP - it's great! :-) (I hope I'm not too annoying continuing this discussion...I sense some irritation, "we have already explained", on this matter :-) Previous Comments: ------------------------------------------------------------------------ [2004-03-31 03:12:23] helly@php.net Since you don't believe us: http://docs.sun.com/source/806-3568/ncg_goldberg.html ------------------------------------------------------------------------ [2004-03-30 21:40:21] gschlossnagle@php.net Floating point values in computers are never exact. It's a fact of life, and an issue that is not only encountered with PHP but other languages as well. ------------------------------------------------------------------------ [2004-03-30 21:35:54] t dot steve at ariadne-quatra dot com Hi! I am sure I am something, apologies for that. :( "Guys, how in the world is PHP supposed to magically guess what precision you want results displayed in." 141.23 - 141 _is_ precisely 0.23. If I was asking for 1/3, then I would understand the decimal places. But how come 141.23-141 turns out to have so many decimal places in the end instead of just being 0.23 - the mathematically correct and precise result? ------------------------------------------------------------------------ [2004-03-30 19:59:05] rasmus@php.net Guys, how in the world is PHP supposed to magically guess what precision you want results displayed in. If you know you always want lower precision, set that in your php.ini file. Or if you just want it temporarily simply do: $old = ini_set('precision',2); echo (string)(750 - 749.99); ini_set('precision',$old); ------------------------------------------------------------------------ [2004-03-30 19:47:47] alan_k@php.net create table a ( b float,c float ); Query OK, 0 rows affected (0.11 sec) mysql> insert into a (b,c) values (141.23,141); Query OK, 1 row affected (0.07 sec) mysql> select b-c from a; +------------------+ | b-c | +------------------+ | 0.22999572753906 | +------------------+ 1 row in set (0.00 sec) ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/27744 -- Edit this bug report at http://bugs.php.net/?id=27744&edit=1