Success with Extra Credit project (Ben Jakuben course)

from appDelegate.m
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.window.backgroundColor = [UIColor grayColor];

    MainViewController *viewController = [[MainViewController alloc] init];

    self.window.rootViewController = viewController;

    [self.window makeKeyAndVisible];
    return YES;
}

from MainViewController.m
//
//  MainViewController.m
//  TabBarMe
//
//  Created by Admin on 4/4/15.
//  Copyright (c) 2015 Wood and Wire Ware. All rights reserved.
//

#import "MainViewController.h"

@interface MainViewController ()
@property (nonatomic, strong) UITextField *textField;
@property (nonatomic, strong) UILabel *titleLabel;
@property (nonatomic, strong) UILabel *label;
@property (nonatomic, strong) UILabel *credit;
@end

@implementation MainViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.titleLabel = [[UILabel alloc] initWithFrame:CGRectMake(20.0f, 120.0f, 340.0f, 30.0f)];
    self.titleLabel.text = @"Extra Credit: Dynamic Tabs sans Storyboard";
    self.titleLabel.textColor = [UIColor whiteColor];
    [self.view addSubview:self.titleLabel];

    self.label = [[UILabel alloc] initWithFrame:CGRectMake(40.0f, 150.0f, 320.0f, 30.0f)];
    self.label.text = @"Please enter number of tabs to display";
    [self.view addSubview:self.label];

    self.textField = [[UITextField alloc] initWithFrame:CGRectMake(140.0f, 180.0f, 100.0f, 30.0f)];
    self.textField.delegate = self;
    self.textField.borderStyle = UITextBorderStyleRoundedRect;
    [self.view addSubview:self.textField];

    UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    button.frame = CGRectMake(120.0f, 230.0f, 150.0f, 30.0f);
    [button addTarget:self action:@selector(buttonPressed) forControlEvents:UIControlEventTouchUpInside];
    [button setTitle:@"Tap to Display Tabs" forState:UIControlStateNormal];
    [button setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
    [self.view addSubview:button];

    self.credit = [[UILabel alloc] initWithFrame:CGRectMake(120.0f, 600.0f, 140.0f, 30.0f)];
    self.credit.text = @"Jim Goodin, 2015";
    self.credit.textColor = [UIColor blackColor];
    [self.view addSubview:self.credit];
}

- (BOOL)textFieldShouldReturn:(UITextField *)textField {
    // may not be necessary but implemented
    [textField resignFirstResponder];
    return NO;
}

- (void)buttonPressed {
   // launches TabBar view(s) 
   [self createTabBar];
}

- (void)buttonPressed2 {
    // return to home view viewController
    [self.tbc dismissViewControllerAnimated:self.tbc completion:nil];
}

- (void)createTabBar {
    // create and load tabbar with number of tabs created
    // based on user input
    NSInteger a;

    self.tbc = [[UITabBarController alloc] init];
    UIViewController *firstVC = [[UIViewController alloc] initWithNibName:nil bundle:nil];
    firstVC.view.backgroundColor = [UIColor blueColor];
    UIViewController *secondVC = [[UIViewController alloc] initWithNibName:nil bundle:nil];
    secondVC.view.backgroundColor = [UIColor redColor];
    UIViewController *thirdVC = [[UIViewController alloc] initWithNibName:nil bundle:nil];
    thirdVC.view.backgroundColor = [UIColor greenColor];
    UIViewController *fourthVC = [[UIViewController alloc] initWithNibName:nil bundle:nil];
    fourthVC.view.backgroundColor = [UIColor orangeColor];
    UIViewController *fifthVC = [[UIViewController alloc] initWithNibName:nil bundle:nil];
    fifthVC.view.backgroundColor = [UIColor darkGrayColor];

    firstVC.tabBarItem.title = @"1";
    secondVC.tabBarItem.title = @"2";
    thirdVC.tabBarItem.title = @"3";
    fourthVC.tabBarItem.title = @"4";
    fifthVC.tabBarItem.title = @"5";

    [self evaluateTabBar:a];
    a = [self.textField.text integerValue];
    if (a == 1) {
        NSArray *array = [[NSArray alloc] initWithObjects:firstVC, nil];
        self.tbc.viewControllers = array;
        [self addButtonToEachView];
    }
    if (a == 2) {
        NSArray *array = [[NSArray alloc] initWithObjects:firstVC, secondVC, nil];
        self.tbc.viewControllers = array;
        [self.view addSubview:self.tbc.view];
        [self addButtonToEachView];
    }
    if (a == 3) {
        NSArray *array = [[NSArray alloc] initWithObjects:firstVC, secondVC, thirdVC, nil];
        self.tbc.viewControllers = array;
        [self.view addSubview:self.tbc.view];
        [self addButtonToEachView];
    }
    if (a == 4) {
        NSArray *array = [[NSArray alloc] initWithObjects:firstVC, secondVC, thirdVC, fourthVC, nil];
        self.tbc.viewControllers = array;
        [self.view addSubview:self.tbc.view];
        [self addButtonToEachView];
    }
    if (a == 5) {
        NSArray *array = [[NSArray alloc] initWithObjects:firstVC, secondVC, thirdVC, fourthVC, fifthVC, nil];
        self.tbc.viewControllers = array;
        [self.view addSubview:self.tbc.view];
        [self addButtonToEachView];
    }
}

- (NSInteger)evaluateTabBar:(NSInteger)answer {
    // user responds to prompt for how many tabs he wants on the bar
    return answer;
}

- (void)addButtonToEachView {
    [self presentViewController:self.tbc animated:YES completion:nil];
    UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    button.frame = CGRectMake(120.0f, 200.0f, 130.0f, 30.0f);
    [button addTarget:self action:@selector(buttonPressed2) forControlEvents:UIControlEventTouchUpInside];
    [button setTitle:@"Unload TabBar" forState:UIControlStateNormal];
    [button setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
    [self.tbc.view addSubview:button];
}
@end