What is wrong with this password update process?

PHP Code:

class Newpassword extends CI_Controller {
  private $token = ''; 


You pass it to a method, but it's empty.

PHP Code:

// add()
    $token = $this->token;

    if ($this->Usermodel->set_new_password($token, $enc_password)) { 


PHP Code:

<?php echo form_open(base_url('newpassword/add')); ?>