#39425 [Opn->Bgs]: Specific BUG in DOUBLE mathematics!!!

ID: 39425 Updated by: pajoye@php.net Reported By: jvano at read dot sk -Status: Open +Status: Bogus Bug Type: *General Issues Operating System: Irrelevant (All) PHP Version: 5.2.0 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: ------------------------------------------------------------------------ [2006-11-08 08:04:10] jvano at read dot sk Description: ------------ Problem is in all versions of PHP. Problem is in basic mathematic operation (+/-) wiht double. When I use simple values and make some basic operation, for example (5.7 - (1.4 + 4.3)). This problem is in another combinations but not in all. Reproduce code: --------------- <?php echo (5.7 - (1.4 + 4.3)); ?> Expected result: ---------------- In all cases is expected 0(zero). But result is always +/- 8.881784197E-016. Actual result: -------------- I think that problem is in representation of double value. ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=39425&edit=1