iOS Application without storyboard

No storyboard

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
                            
    var window: UIWindow?

    func application(application: UIApplication!, didFinishLaunchingWithOptions launchOptions: NSDictionary!) -> Bool {
        window = UIWindow(frame: UIScreen.mainScreen().bounds)
        if let window = window {
            window.backgroundColor = UIColor.whiteColor()
            window.makeKeyAndVisible()
            window.rootViewController = ViewController()
        }
        return true
    }
}