note 102796 added to function.ceil

The code below rounds a value up to a nearest multiple, away from zero. The multiple does not have to be a integer. So you could round, say, to the nearest 25.4, allowing you to round measurements in mm to the nearest inch longer. <?php // $x is the variable // $c is the base multiple to round to, away from zero $result = ( ($y = $x/$c) == ($y = (int)$y) ) ? $x : ( $x>=0 ?++$y:--$y)*$c ; ?> I originally developed this as an example of write-only code: to make the point that being cleverly terse might save clock ticks but wastes more in programmer time generating un-maintainable code. The inline code above nests one conditional statement inside another. The value of y changes twice within the same line (three times, if you count the pre-increment). The value of each assignment is used to determine branching within the conditional statement. How it works can more easily be seen from the expansion below: <?php function myCeilingLong($x,$c) { // $x is variable // $c is ceiling multiple $a = $x/$c ; $b = (int)$a ; if ($a == $b) return $x ; // x is already a multiple of c; else { if ($x>=0) return ($b+1)*$c ; // return ((int)(x/c)+1 ) * c else return ($b-1)*$c ; // return ((int)(x/c)-1 ) * c } } ?> <?php function myCeilingShort($x,$c) { return ( ($y = $x/$c) == ($y = (int)$y) ) ? $x : ( $x>=0 ?++$y:--$y)*$c ; } ?> Comparing the versions for speed: the in-line version is about three times faster than myCeilingLong() - but this is almost entirely down to function call overhead. Putting the in-line code inside the function: the difference in execution speed between myCeilingLong() and myCeilingShort() is around 1.5%. ceil() is still around 25% faster than the in-line statement so if you are a speed hound your efforts might be better devoted to compiling your own library ... ---- Server IP: 92.48.74.199 Probable Submitter: 195.112.2.119 ---- Manual Page -- http://www.php.net/manual/en/function.ceil.php Edit -- https://master.php.net/note/edit/102796 Del: integrated -- https://master.php.net/note/delete/102796/integrated Del: useless -- https://master.php.net/note/delete/102796/useless Del: bad code -- https://master.php.net/note/delete/102796/bad+code Del: spam -- https://master.php.net/note/delete/102796/spam Del: non-english -- https://master.php.net/note/delete/102796/non-english Del: in docs -- https://master.php.net/note/delete/102796/in+docs Del: other reasons-- https://master.php.net/note/delete/102796 Reject -- https://master.php.net/note/reject/102796 Search -- https://master.php.net/manage/user-notes.php