Creating array of quiz questions that do not repeat - xcode

Question

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?

Answer 1

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.