Routing Number (371) Sum Check Algo in PHP

Routing Number Check Sum Algorithm in PHP (371 371 371).  Check it out.


<?php


    function routingNumberCheckSum($routingNumber)
    {
       
       
        $routingArray = array();
        $total = 0;
        $i = 0;
       
        for($i = 0; $i < strlen($routingNumber); $i++)
                    {
                      
                           if (!isset($routingArray[$i])) {$routingArray[$i] = 0;}
                      
                        $routingArray[$i] = intval(substr($routingNumber,$i,1));
                      
                          
                          
                        if ( $i % 3 == 0 )
                        { 
                            $routingArray[$i] = $routingArray[$i] * 3;
                          
                              
                        }
                        elseif ($i % 3 == 1)
                        {
                          
                            $routingArray[$i] = $routingArray[$i] * 7;
                          
                        }
  
                          
                        $total = $total + $routingArray[$i];
                    }
                  
                   
                  
                    if ($total % 10 === 0)
                    {
                        return "true";
                    }
                    else
                    {
                        return "false";
                    }
                }
   
   



?>