<?php
  /*
   * App Core Class
   * Creates URL & loads core controller
   * URL FORMAT - /controller/method/params
   */
 class Core {
    protected $currentController = 'Pages';
    protected $currentMethod = 'index';
    protected $params = [];
public function __construct(){
      //print_r($this->getUrl());
      $url = $this->getUrl();
      // Look in controllers for first value
      if(file_exists('../app/controllers/' . ucwords($url[0]). '.php')){
        // If exists, set as controller
        $this->currentController = ucwords($url[0]);
        // Unset 0 Index
        unset($url[0]);
      }
      // Require the controller
      require_once '../app/controllers/'. $this->currentController . '.php';
      // Instantiate controller class
      $this->currentController = new $this->currentController;
      // Check for second part of url
      if(isset($url[1])){
        // Check to see if method exists in controller
        if(method_exists($this->currentController, $url[1])){
          $this->currentMethod = $url[1];
          // Unset 1 index
          unset($url[1]);
        }
      }
  
// Get params
      $this->params = $url ? array_values($url) : [];
      // Call a callback with array of params
      call_user_func_array([$this->currentController, $this->currentMethod], $this->params);
    }
public function getUrl(){
      if(isset($_GET['url'])){
        $url = rtrim($_GET['url'], '/');
        $url = filter_var($url, FILTER_SANITIZE_URL);
        $url = explode('/', $url);
        return $url;
      }
    }
  } 
  
Above code contain an error like this otice: Trying to access array offset on value of type null in H:\xampp\htdocs\ecommerce\app\libraries\Core.php on line 18
require_once '../app/controllers/'. $this->currentController . '.php';
this is the line. When I enter website with domain.com then show this error and when i enter domian.com/post then it has no problem
 
     
    