Macfeteria

// ------- Interface -------------------------
@interface NSMutableArray (QueueAdditions)
- (id) dequeue;
- (void) enqueue:(id)obj;
@end
 
 
 
 
// ------- Implement -------------------------
@implementation NSMutableArray (QueueAdditions)
// Queues are first-in-first-out, so we remove objects from the head
- (id) dequeue {
    // if ([self count] == 0) return nil; // to avoid raising exception (Quinn)
    id headObject = [self objectAtIndex:0];
    if (headObject != nil) {
        [[headObject retain] autorelease]; // so it isn't dealloc'ed on remove
        [self removeObjectAtIndex:0];
    }
    return headObject;
}
 
// Add to the tail of the queue (no one likes it when people cut in line!)
- (void) enqueue:(id)anObject {
    [self addObject:anObject];
    //this method automatically adds to the end of the array
}
@end

// ------- Interface -------------------------
@interface NSMutableArray (StackAdditions)
- (id)pop;
- (void)push:(id)obj;
@end
 
// ------- Implement -------------------------
@implementation NSMutableArray (StackAdditions)
- (id)pop
{
    // nil if [self count] == 0
    id lastObject = [[[self lastObject] retain] autorelease];
    if (lastObject)
        [self removeLastObject];
    return lastObject;
}
 
- (void)push:(id)obj
{
     [self addObject: obj];
}
 
@end