base_url() doesn't show, weird @__@

[eluser]solid9[/eluser]
I installed a new CodeIgniter into my site.

I already configured the config.php

Code:

$config['base_url'] = 'http://sample.com/adminpro/';

And below is my controller

Code:

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Front extends MY_Controller
{

    function __construct ()
    {
        parent::__construct();

    }

public function index()
{
        echo 'Front controller';
  
    //$this->load->view('welcome_message', $this->data);
    $this->load->view('template/master');
}

public function hello()
{  
  echo '<br>Hello World!<br>';
  echo base_url();
}
}

But when I call http://sample.com/adminpro/front/hello/

It doesn't display the base_url(), any help.

weird.