How to Share View Controllers for iPhone and iPad Using Nibs for Reuse and Portability

AppDelegate.m

#import "SLMainViewController.h"

AppDelegate_2.m

// Override point for customization after application launch.
SLMainViewController *mainViewController = [[SLMainViewControlleralloc] init];
self.window.rootViewController = mainViewController;

SLMainViewController.m

-(NSString *)nibName {
  return @"SLMainViewController"
}

SLMainViewController_2.m

@interface SLMainViewController ()
@property (weak, nonatomic) IBOutlet UILabel *greetingLabel;
@end

SLMainViewController_3.m

- (void)viewDidLoad {
  [super viewDidLoad];
  // Do any additional setup after loading the view from its nib.
  self.greetingLabel.text = [NSString stringWithFormat:"%@ %@", self.greetingLabel.text, "Vinny"];
}