CODEWITHSUNDEEP
xcoderandomnsmutablearray
user1759949
user1759949

Reputation: 199

Creating array of quiz questions that do not repeat

I'm trying to create a basic quiz app where the questions will not repeat. I've looked at several examples and believe I should be storing the questions in an array and then removing one from the array each time its used. I've tried the following code.

- (void)viewDidLoad
{
//The array of questions
NSMutableArray *questionArray = [[NSMutableArray alloc] initWithObjects: 
    [NSMutableArray arrayWithObjects:@"First Question",@"Answer A", nil],
    [NSMutableArray arrayWithObjects:@"Second Quesiton",@"AnswerA",@"AnswerB", nil],
                                 nil];


//remove used question from array
for (int i = questionArray.count; i>=0; --i) {
    _questions = [questionArray objectAtIndex:arc4random() % questionArray.count];

    [questionArray exchangeObjectAtIndex:i withObjectAtIndex:_questions];
}

//use array object
self.lblQuestion.text = [_questions objectAtIndex:0];
[self.btnA setTitle:[_questions objectAtIndex:1] forState:UIControlStateNormal];

[super viewDidLoad];
}

I'm getting the following warning: Incompatible pointer to integer conversion sending NSMutableArray*_strong to parameter of type 'NSUInteger'

I take it this means I shouldn't be using another array to store the random question as I can't use this to remove the question from the array. However I don't know how else to do this?

Am I completely misunderstanding how I should go about this?

Upvotes: 0

Views: 1453

Answers (1)

Jad El Jerdy
Jad El Jerdy

Reputation: 46

Since your goal here is to get non-repeating questions...

I believe that instead of removing the question you have already used, you should SHUFFLE your array at the beginning and then loop through the array one index at a time using a simple counter.

I hope you can find this piece of code helpful -- give it a shot:

-(NSMutableArray *)shuffleArray:(NSMutableArray *)anArray
    NSUInteger count = [anArray count];
    for (NSUInteger i = 0; i < count; ++i) 
    {
        int nElements = count - i;
        int n = (arc4random() % nElements) + i;
        [anArray exchangeObjectAtIndex:i withObjectAtIndex:n];
    }

    return anArray;
}

-(void)viewDidLoad
{
    //The array of questions
    NSMutableArray *questionArray = [[NSMutableArray alloc] initWithObjects: 
    [NSMutableArray arrayWithObjects:@"First Question",@"Answer A", nil],
    [NSMutableArray arrayWithObjects:@"Second Quesiton",@"AnswerA",@"AnswerB", nil],
                             nil];

    //Shuffle the question array -- Now all indexes are shuffled and Random
    questionArray = [self shuffleArray:questionArray];

    //Every time you want to move to the next question, all you have to do is connect a button to the nextIndex action and let it do all the work!
    //Use the nextIndex method to initialise -- we call it manually the first time so things would get going and something is displayed -- you can remove the line below if you want it to initialise on first button click! Your call the shots sir!
    [self nextIndex];


    [super viewDidLoad];
}

//Edit -- This method shows how to change question array index using a method
int currentIndex = 0;
-(IBAction)nextIndex
{
    if ( currentIndex == [questionArray count] )
    {
        currentIndex = 0; //Resets the var when getting to the final Index
        //The above line will result in a question loop -- meaning if you arrive at the last question, the next question will be the first! Pacman mode!
        //If you want to stop at the last question just change the above line to return; and you're all set!
    }

    //Set _questions object to the current Index Array element
    _questions = [questionArray objectAtIndex:currentIndex];

    //Increment currentIndex for next use
    currentIndex++;

    //use the array object to set your objects' values
    self.lblQuestion.text = [_questions objectAtIndex:0];
    [self.btnA setTitle:[_questions objectAtIndex:1] forState:UIControlStateNormal];
}

You will end up having totally different questions that are shuffled every time.

I hope you find this helpful.

Upvotes: 1

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