How to switch views programmatically in a ViewController?

gistfile1.txt

talk with segue :

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
       //TODO:
            // showShop(shop: shops[indexPath.row])
        performSegue(withIdentifier: "ShopIdentifire", sender: indexPath)
    
    }
    
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "ShopIdentifire" {
           let controller = segue.destination as! ShopMenuController
            controller.shop = shops[(sender as! IndexPath).row]
            
        }
    }
    
 
 WithOut segue use Identifire 
    
**If you are in a Navigation Controller:**

    let viewController: ViewController = self.storyboard?.instantiateViewControllerWithIdentifier("VC") as ViewController
    self.navigationController?.pushViewController(viewController, animated: true)

**Or if you just want to present a new view:**

    let viewController: ViewController = self.storyboard?.instantiateViewControllerWithIdentifier("VC") as ViewController
    self.presentViewController(viewController, animated: true, completion: nil)
    


 Programaticaly UINavigation View Controller . it is not in Appdelageted:

class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?


    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        
//        
//        //configur stripe account 
//        STPPaymentConfiguration.shared().publishableKey = "pk_test_vEvSUgGexfEiKq48HXVzSzuZ"
//        
//        // Override point for customization after application launch.
        window = UIWindow(frame: UIScreen.main.bounds)
        window?.makeKeyAndVisible()
//
//        
//       // for colleciton view
//        
      let layout = UICollectionViewFlowLayout()
      window?.rootViewController = UINavigationController(rootViewController: LandingPageController(collectionViewLayout: layout))
       
        //for table view or normal view 
      // window?.rootViewController = UINavigationController(rootViewController: RestaurantViewController())

        return true
    }
  }



 Programaticaly UINavigation View Controller . it is not in the  Appdelageted:
 
        let viewController = RestaurantViewController()
        
        let navigationController = UINavigationController.init(rootViewController: viewController)
        
        self.present(navigationController, animated: true, completion: nil)