note 119583 added to language.types.float

Hint to overcome some imprecisions during various subtractions in sequence. I was making a sequence of subtractions and I expected 0 as a result and I had put an if statement asking if the variable value was >= 0, for my surprise it gave me a negative number. The subtraction was 0.03 - 0.01 - 0.005 - 0.005 - 0.01 and the result was -5.2041704279304E-18. So I had to make a sum to subtract later, like this: <?php $a = 0.03 $b = 0.01 + 0.005 + 0.005 + 0.01 $res = $a - $b ?> So, finally, I could get the right result I didn't expect to get floating point precision problems with this simple subtraction. It was a pain to solve the problem, because you never remember that floating point math has it's issues. ---- Server IP: 72.52.91.14 Probable Submitter: 191.251.23.214 ---- Manual Page -- http://php.net/manual/en/language.types.float.php Edit -- https://master.php.net/note/edit/119583 Del: integrated -- https://master.php.net/note/delete/119583/integrated Del: useless -- https://master.php.net/note/delete/119583/useless Del: bad code -- https://master.php.net/note/delete/119583/bad+code Del: spam -- https://master.php.net/note/delete/119583/spam Del: non-english -- https://master.php.net/note/delete/119583/non-english Del: in docs -- https://master.php.net/note/delete/119583/in+docs Del: other reasons-- https://master.php.net/note/delete/119583 Reject -- https://master.php.net/note/reject/119583 Search -- https://master.php.net/manage/user-notes.php