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Luhn algorithm Troubles


TheJoey

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hi im trying to use credit card validation Luhn algorithm.

im storing it in a seperate php and including it on my needed page

<?php 
/* Luhn algorithm number checker - (c) 2005-2008 - planzero.org            *
* This code has been released into the public domain, however please      *
* give credit to the original author where possible.                      */

function luhn_check($number) {

  // Strip any non-digits (useful for credit card numbers with spaces and hyphens)
  $number=preg_replace('/\D/', '', $number);

  // Set the string length and parity
  $number_length=strlen($number);
  $parity=$number_length % 2;

  // Loop through each digit and do the maths
  $total=0;
  for ($i=0; $i<$number_length; $i++) {
    $digit=$number[$i];
    // Multiply alternate digits by two
    if ($i % 2 == $parity) {
      $digit*=2;
      // If the sum is two digits, add them together (in effect)
      if ($digit > 9) {
        $digit-=9;
      }
    }
    // Total up the digits
    $total+=$digit;
  }

  // If the total mod 10 equals 0, the number is valid
  return ($total % 10 == 0) ? TRUE : FALSE;

}

?>

 

im trying to use it like this but its not working.

if ($errorluhn) $errorluhn = "luhn validation";
$luhn = isset($_POST['luhn']) ? trim($_POST['luhn']) : '';
if (luhn_check($luhn) $errorluhn = true;

 

 

if (luhn_check($luhn) $errorluhn = true;

that line is the acutally line where im getting trouble with

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