(iOS) Creating a tab bar

AppDelegate.mm

//Create for every single view you're going to have a new view controller class
//Subclass of UIViewController
//With a correspoding .xib
//.
//Creating outlet for the root controller (which will be a tab bar) in the delegate .h file
@property (strong, nonatomic) IBOutlet UITabBarController *tabBarController;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.
    
    /*****************************************************************************/
    //We’re using a controller class provided by Apple (UITabBarController) instead of one we wrote ourselves.
    //See header file
    
    //Show the TabBarController.xib
    [[NSBundle mainBundle] loadNibNamed:@"TabBarController" owner:self options:nil];
    
    //Set the root controller to the outlet we set pointing to the Tab bar controller (UITabBarController)
    self.window.rootViewController = self.tabBarController;
    /*****************************************************************************/
    
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];
    return YES;
}

//Then create an empty .xib (named after the one in loadNibNamed:) and add a view controller object
//Change the File's Owner class of the xib to the delegate's one (ex. AppDelegate)
//At the connection inspector find the outlet we created in the delegate's .h file and connect it
//to the tab bar Controller
//.
//Add as many tab bar items you want to the tab bar.
//Then change every controller of each tab bar the NIB Name and the Class to the one you're going
//to show.
//.
//Select every tab bar item and customize it as you wish
//Your tab bar is ready

tabBarProgrammaticallyDelegate.mm

- (void)applicationDidFinishLaunching:(UIApplication *)application 
{
   tabBarController = [[UITabBarController alloc] init];

   MyViewController* vc1 = [[MyViewController alloc] init];
   MyOtherViewController* vc2 = [[MyOtherViewController alloc] init];

   NSArray* controllers = [NSArray arrayWithObjects:vc1, vc2, nil];
   tabBarController.viewControllers = controllers;

   // Add the tab bar controller's current view as a subview of the window
   [window addSubview:tabBarController.view];
}