Question

so I am new at the idea of recursion and i wrote this simple code to factor a number ($n) this is the code:

$n = 120;
$y = 1;

function factor($n, $y) {
    if($y > $n) {
        return 1;
    } else {
        $x = $n / $y;
        list($whole, $dec) = array_pad(explode('.', $x), 2, Null);
        if($dec == '') {
            echo 'x:' . $x . ' y:' . $y . '</br>';
            return factor($n, ($y + 1));
        }
    }
}

this is what the code outputs:

x:120 y:1
x:60 y:2
x:40 y:3
x:30 y:4
x:24 y:5
x:20 y:6

so my question is why does this stop before it completes?

Answer 1

Your next step would be 120 / 7 which equals 17.142857….

So this check fails and as such the recursion does not happen:

if($dec=='') // $dec would equal to 142857.....
{
    echo'x:'.$x.' y:'.$y.'</br>';
    return factor($n,($y+1));
}