title: How to use global variables in codeigniter?
body: <p>I am developing an application in codeigniter containing different modules e.g buyer, seller, public. All these modules use same header file. I want a global variable declared in buyer, seller and public controller so that when I load views of one module this variable should help customizing parts of header for seller depending upon its value. Same goes for buyer and public modules.</p>
  
  <p>I want to ask what is the way to have a variable declared at controller scope and then use its value in its views. I have tried declaring and assigning its value in constructor but I get undefined variable error when loading the views. I also tried this way:</p>
  
  <pre><code>class Seller extends CI_Controller {
  
  public $pagetype="seller";
  public function __construct()
      {
          parent::__construct();
      }
  </code></pre>
  
  <p>But I still get undefined variable error. 
  I can pass value of page type when loading view but I have to do that for each view, which is bad and cumbersome way because I have around 25-30 views in each controller.</p>
  
  <p>Any help?</p>