Edit report at https://bugs.php.net/bug.php?id=61787&edit=1
ID: 61787 Updated by: ras...@php.net Reported by: ubuntu at spacetrace dot org Summary: money_format round error Status: Not a bug Type: Bug Package: Math related Operating System: Linux ubuntu 11.04 PHP Version: 5.3.10 Block user comment: N Private report: N New Comment: How does always rounding down fix anything? What if you are trying to do 3.0 but you actually get 2.999999999999999, if you always round down you would get 2 instead of 3. Previous Comments: ------------------------------------------------------------------------ [2012-04-21 17:28:38] ubuntu at spacetrace dot org ah ok, that explains the behaviour. wouldnt it be senseful, if php would always floor the float variable then? or at least throw a notice error, if you parse a float through "%.2i"? i understand this is not a senseful programm-style. cause you get an unpredictable behaviour. if money_format() would round down always, then it would be predictable are there more functions that would show the same behaviour like in this example? what about printf() ------------------------------------------------------------------------ [2012-04-21 14:59:48] ras...@php.net Did you visit the site we provided that explains this? What you think is 7.005 is actually represented as 7.004999999999999999 whereas 8.005 is 8.005000000000000000001 That's what limited precision means. Go read http://www.floating-point-gui.de/ for a complete explanation. ------------------------------------------------------------------------ [2012-04-21 10:11:02] ubuntu at spacetrace dot org so why does php round 7.005 down to 7.00 while it rounds 8.005 correctly up to 8.01 ? and why from 16 on again wrong and from 32 on again correct, from 64 on again wrong but now not a change from 128 on? ------------------------------------------------------------------------ [2012-04-20 16:04:57] johan...@php.net 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://www.floating-point-gui.de/ Thank you for your interest in PHP. . ------------------------------------------------------------------------ [2012-04-20 13:38:17] ubuntu at spacetrace dot org Description: ------------ if you round with money_format, some small numbers with 0.005 are rounded down instead of up. Numbers bigger than 63.5 are all rounded falsly down like with floor() Test script: --------------- for($i=0;$i<70;$i++) { echo($i.'.005 =>'.money_format('%.2i',$i+0.005).'<br>'); if($i<10) echo($i.'.00500000000000001=>'.money_format('%.2i',$i+0.00500000000000001).'<br>'); } Expected result: ---------------- 0.005 =>0.01 0.00500000000000001=>0.01 1.005 =>1.01 1.00500000000000001=>1.01 2.005 =>2.01 2.00500000000000001=>2.01 3.005 =>3.01 3.00500000000000001=>3.01 4.005 =>4.01 4.00500000000000001=>4.01 5.005 =>5.01 5.00500000000000001=>5.01 6.005 =>6.01 6.00500000000000001=>6.01 7.005 =>7.01 7.00500000000000001=>7.01 8.005 =>8.01 8.00500000000000001=>8.01 9.005 =>9.01 9.00500000000000001=>9.01 10.005 =>10.01 11.005 =>11.01 12.005 =>12.01 13.005 =>13.01 14.005 =>14.01 15.005 =>15.01 16.005 =>16.01 ... Actual result: -------------- 0.00500000000000001=>0.01 1.005 =>1.00 1.00500000000000001=>1.01 2.005 =>2.00 2.00500000000000001=>2.00 3.005 =>3.00 3.00500000000000001=>3.00 4.005 =>4.00 4.00500000000000001=>4.00 5.005 =>5.00 5.00500000000000001=>5.00 6.005 =>6.00 6.00500000000000001=>6.00 7.005 =>7.00 7.00500000000000001=>7.00 8.005 =>8.01 8.00500000000000001=>8.01 9.005 =>9.01 9.00500000000000001=>9.01 10.005 =>10.01 11.005 =>11.01 12.005 =>12.01 13.005 =>13.01 14.005 =>14.01 15.005 =>15.01 16.005 =>16.00 17.005 =>17.00 18.005 =>18.00 19.005 =>19.00 20.005 =>20.00 21.005 =>21.00 22.005 =>22.00 23.005 =>23.00 24.005 =>24.00 25.005 =>25.00 26.005 =>26.00 27.005 =>27.00 28.005 =>28.00 29.005 =>29.00 30.005 =>30.00 31.005 =>31.00 32.005 =>32.01 33.005 =>33.01 34.005 =>34.01 35.005 =>35.01 36.005 =>36.01 37.005 =>37.01 38.005 =>38.01 39.005 =>39.01 40.005 =>40.01 41.005 =>41.01 42.005 =>42.01 43.005 =>43.01 44.005 =>44.01 45.005 =>45.01 46.005 =>46.01 47.005 =>47.01 48.005 =>48.01 49.005 =>49.01 50.005 =>50.01 51.005 =>51.01 52.005 =>52.01 53.005 =>53.01 54.005 =>54.01 55.005 =>55.01 56.005 =>56.01 57.005 =>57.01 58.005 =>58.01 59.005 =>59.01 60.005 =>60.01 61.005 =>61.01 62.005 =>62.01 63.005 =>63.01 64.005 =>64.00 65.005 =>65.00 66.005 =>66.00 67.005 =>67.00 68.005 =>68.00 69.005 =>69.00 from 64 on all numbers are rounded down like floor() ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=61787&edit=1
