QuizViewController.h

#import <UIKit/UIKit.h>

@interface QuizViewController : UIViewController
{
    int currentQuestionIndex;

    // the model objects, pointers here. Referenced in QuizViewController.m
    NSMutableArray *questions;
    NSMutableArray *answers;
    
    // the view objects - don't worry about IBOutlet, we'll get there shortly
    IBOutlet UILabel *questionField;
    IBOutlet UILabel *answerField;
//    IBOutlet UILabel *thingField;
//    IBOutlet UILabel *fooField;
//    IBOutlet UILabel *NBSField;
//    These show up in the Outlets section when right clicking on the File Owner
}

- (IBAction)showQuestion:(id)sender;
- (IBAction)showAnswer:(id)sender;
// These show up in the Received Actions section when clicking on File Owner

// IBOutlet and IBAction let me connect the controller and view objects in the Storyboard/XIB file

@end

QuizViewController.m

#import "QuizViewController.h"

@interface QuizViewController ()

@end

@implementation QuizViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    // call the init method implemented by the superclass
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // create two arrays and make the pointers point to them
        questions = [[NSMutableArray alloc] init];
        answers = [[NSMutableArray alloc] init];
        
        // add quetions and answers to the arrays
        [questions addObject:@"What is 7 + 7?"];
        [answers addObject:@"14"];
        
        [questions addObject:@"What is the capitol of Vermont?"];
        [answers addObject:@"Montpelier"];
        
        [questions addObject:@"From what is cognac made?"];
        [answers addObject:@"Grapes"];
    }
    // return the address of the new object
    return self;
}

- (IBAction)showQuestion:(id)sender
{
    // Step to the next question
    currentQuestionIndex++;
    
    // Am I past the last question?
    if (currentQuestionIndex == [questions count]) {
        // Go back to the first question
        currentQuestionIndex = 0;
    }
    
    // Get the string at that index in the questions array
    NSString *question = [questions objectAtIndex:currentQuestionIndex];
    
    // Log the string to the console
    NSLog(@"displaying question: %@", question);
    
    // Display the string in the question field
    [questionField setText:question];
    
    // Clear the answer field
    [answerField setText:@"???"];
}

- (IBAction)showAnswer:(id)sender
{
    // What is the answer to the current question?
    NSString *answer = [answers objectAtIndex:currentQuestionIndex];

    // Display it in the answer field
    [answerField setText:answer];
}

- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end