UNSW ProgComp: Problem 3 - 2005

<?php

$input = <<<END
0-413-72490-3
0-413-72490-5
0-9751194-0-0
1-56592-286-X
1234567890
123456789X
0123456789
X123456789
---0-1-2-3-4-5-6-7-8-9---
0600.587495
052148342
05214834255
#1&1+1,1;1:1|1>1.1$1
END;

$input = explode("\n", $input);

$strip_values = array(',', '.', '/', "'", '<', '>', '?', ';', ':', '[', '{', ']', '}', '`', '~', '!', '@', '#', '$', '%', '^', '&', '*', '(', ')', '_', '-', '+', '=');
//Who would do such a thing!!

foreach($input as $key => $value){
    $uneditted_line = $value;
    $line = str_replace($strip_values, "", trim($value));

    $sum = 0;
    for($c = 1; $c < strlen($line); $c++){
        $sum += $line[$c-1]*$c;
        //echo $line[$c-1]."\n";
    }
    $check = $sum%11;
    if($check == 10){
        $check = 'X';
    }
    if($check == substr($line, -1)){
        print $uneditted_line." is a valid ISBN";
    }else{
        print $uneditted_line." is not a valid ISBN, the check character should be $check";
    }

    if($key != count($input)-1){
        print "\n";
    }
}