Programmatically instantiate ViewController in AppDelegate

gistfile1.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    
    self.window.backgroundColor = [UIColor clearColor];
    
    ViewController *viewController = [[ViewController alloc] init];
    
    self.window.rootViewController = viewController;
    
    [self.window makeKeyAndVisible];
    
    return YES;
}