<?php class Rumus extends CI_Controller {       function __construct()     {         parent::__construct();     }           function index()     {                   $data['title'] = "Belajar CodeIgniter";         $data['heading'] = "Selamat Belajar";         $data['content'] = array();         $data['content']['nama'] = "Ismiatul Rafika";                 }           function operasi1($x, $y,$a,$b)     {	         echo "(10x2)/5 + (5-4) = ".((($x*$y)/$a)+($a-$b)); 			$this->load->view('tampilRumus');     } 	 } ?>