The intermediary present between the models and the views to process the HTTP request and is used to generate a web page is known as a controller. It is basically known as the center of each
request that exists on the web application of the user.
Please consider the following URL in this reference,
In this URL the CodeIgniteris basically trying to find the welcome.php file and the Welcome class.Controller Syntax
class ControllerName extends CI_Controller
public function __construct()
public function MethodName()