note 71782 deleted from language.operators.arithmetic by hholzgra

Note Submitter: gilthansREMOVEME at gmail dot com ---- 1) About integer division: here's a function that neatly solves this. It is somewhat slower than normal division, but is failsafe. <?php function integer_divide($x, $y){ //Returns the integer division of $x/$y. $t = 1; if($y == 0 || $x == 0) return 0; if($x < 0 XOR $y < 0) //Mistaken the XOR in the last instance... $t = -1; $x = abs($x); $y = abs($y); $ret = 0; while(($ret+1)*$y <= $x) $ret++; return $t*$ret; } ?> 2) adam.pippin noted about number factoration, however the function returns alot of sequences in text form. This one returns an Array with all the factored numbers of a number. For example, factor(50) would return Array(2, 5, 5). <?php function factor($n){ $ret = Array(); $i = 2; $m = $n/2; while($i <= $m){ if(!($n%$i)) $ret = array_merge($ret, factor($i), factor($n/$i)); if($i%2) $i+=2; //$i is impair else $i++; //Ideally, you'd only run through prime numbers, but there is no way to tell what is the next prime number; we can be sure, however, that the pair ones aren't prime. $m = $n/$i; //If $n isn't divisible by $i, it be assumed it isn't divisible by any number bigger than $n/$i, and if it is divisible by $i, $n/$i is already put in. The derivation for this isn't too complex. This drastically reduces the number of numbers we have to go through during the factoration. } if(empty($ret)) return Array($n); return $ret; } ?> This has only been tested for integers, factoration for floats should include some way to identify the divisor. Hope this saves someone some headaches.