Question

I have built a specialized card application. What it does is allow a user to ‘draw’ a card, then view the card, and place it back in a random place in the deck. The only problem that I am having is that, more often than not, the card is being placed at the top of the deck.

Here is the contents of the .h file:

@class _Card;

@interface _Deck : NSObject

@property (readonly) NSString *deckData;
@property (readonly) NSUInteger count;
@property (readonly) NSUInteger deckCount;
@property (readonly) BOOL needsReset;
@property (readonly) NSArray *cards;

- (id)initWithArray:(NSArray *)array;
- (id)initWithContentsOfFile:(NSString *)filePath;

- (void)shuffle;
- (NSArray *)draw;
- (void)reset;
- (void)changeEdition;

@end

Now, here is my draw method, which will draw a card (more than one if the cards so specify it) and then place that card back into the deck, if it is allowed:

- (NSArray *)draw {

    // first, we create an array that can be returned, populated with the
    // cards that we drew
    NSMutableArray *drawArray = [[[NSMutableArray alloc] init] autorelease];

    // next, we get the top card, which is actually located in the 
    // indexArray (I use this for shuffling, pulling cards, etc.)
    NSNumber *index = [[[indexArray objectAtIndex:0] retain] autorelease];

    // now we get the card that the index corresponds to
    // from the cards array
    _Card *card = [cards objectAtIndex:[index integerValue]];

    // now I remove the index that we 
    // got from the indexArray...don't worry,
    // it might be put back in
    [indexArray removeObject:index];

    // if the card is supposed to discard after
    // draw, we leave it out
    if(!card.discard) {

        int insertIndex = arc4random_uniform(indexArray.count);

        // then I insert the card into the deck using the random, random 
        // number
        [indexArray insertObject:index atIndex:insertIndex];
    }

    _Card *cardCopy = [card copy];

    // we add the card to the array 
    // that we will return
    [drawArray addObject:cardCopy];

    // next, if the card is not the final card...
    if(!card.final) {

        // ...and the card has an 
        // additional draw specified...
        if(card.force) {

            // we keep drawing until we need to stop
            [drawArray addObjectsFromArray:[self draw]];
        }
    }

    return drawArray;
}

Is there anything that I may be doing wrong? If you need any more information, please let me know. Thanks in advance for any help that you can provide.

Answer 1

If I am understanding this correctly, the problem is that it is inserting the card at index 0 in indexArray?

Okay, have you tried something like this:

(don’t use this line yet [indexArray removeObject:index];)

if(!card.discard)
{
    int insertIndex = arc4random_uniform(indexArray.count);
    id obj = [indexArray objectAtIndex:index];
    [indexArray removeObjectAtIndex:index];
    [indexArray insertObject:obj atIndex:insertIndex];
NSLog(@"insertIndex is %i and obj is %@", insertIndex, obj);
}
else
{
    [indexArray removeObjectAtIndex:index];
}

Your code seems to be okay, I’m guessing it just doesn’t like removing the object before… I added the log just so you could see if it really was inserting it at the top each time. Give me an update- if this doesn’t work, I could take a look at your project file.