Some functions in Controller

In Documentation :

PHP Code:

class MY_Input extends CI_Input {

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


And as the documentation says "If you need to use a constructor in your class make sure you extend the parent constructor:"

If you don't have work that must happen in a constructor then you don't need to define a constructor only for purpose of calling parent::__construct(). PHP will take care of that automatically.  

However, if you do define __construct() then you must explicitly call parent::__construct()