PHP Card Number Generator

WHY

Because some sites offer free trials .. you don't want them to charge just for trying .. or you just want to be anonymous !

HOW

function gen_card(){
        $rand = array();
        $rand[] = "4";
        for($i=0;$i<14;$i++){
                $rand[] = rand(0,9);
        }
        $orig = $rand;
        $rand_rev = array_reverse($rand);
        foreach($rand_rev as $cnt => $nr){
                if($cnt%2 == 0){
                        $rand_rev[$cnt] = $nr*2;
                        if($rand_rev[$cnt] >= 10){
                                $nr = str_split($rand_rev[$cnt]);
                                $rand_rev[$cnt] = $nr[0] + $nr[1];
                        }
                }
        }
        $rand = array_reverse($rand_rev);
        $sum = array_sum($rand) * 9;
        $orig = implode('', $orig);
        $sum = str_split($sum);
        $nr = $sum[count($sum)-1];
        return $orig.$nr;
}