Call to undefined method CI_Controller::CI_Controller()

[eluser]huangxiao[/eluser]
Hi already change it as your suggested but i have problem in the redirect(), it will duplicate the url when i submit the form.
something like this.
[qoute]http://localhost/test/index.php/login/localhost/test/index.php/success/members_area[/qoute]

Code:

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

class Login extends CI_Controller{

     function index(){

       $data['maincontent'] = "login_view";
       $this->load->view("include/template",$data);

    }


    function getlogin(){
      $this->load->model('login_model');
   $query =  $this->login_model->login_check();

      if($query){
         $data = array(
             'username'=>$this->input->post('username'),
             'is_logged_in'=>true


         );

          $this->session->set_userdata($data);

          redirect('/success/members_area');

      }


   }

}

This is my form

Code:

<div class='container'>
    
      &lt;form class="login" action="index.php/login/getlogin" method='post'&gt;
        <h2>Log-in</h2>
        
           &lt;input type='text' placeholder="username" name="username"&gt;
           &lt;input type='text' placeholder="password"  name="password"&gt;
           <button type="submit" >Log-in</button>

       &lt;/form&gt;
    </div>