A Queue of Cards
You are going to parallel the development done in the lesson on inheritance where we constructed some base classes, StackNode and Stack, and derived FloatNode and FloatStack from them. You can work best by referring to those modules all through the development of your program. These are the differences between what we did in the lesson and what you will do for your assignment.
- Instead of a Stack data structure, you will create a Queue data structure. A Stack is last-in-first-out (LIFO). A Queue is first-in-first-out (FIFO).
- Instead of deriving a FloatNode from the basic Node class, you will derive a CardNode from Node. CardNode will use the Card class of Week 1.
Here are the details:
Base Class Node
You can use the same class for a base class that was used in the modules. However, I want you to give this class a different name. Call it Node (not QueueNode or StackNode, just Node).
Base Class Queue
Next, do almost the same thing as we did with the Stack class, except make sure that this class works like a Queue, not a Stack. That means
- We add items to the Queue using Add() not Push(). Push() does not appear in our Queue class.
- We retrieve items from the Queue using Remove() not Pop(). Pop() does not appear in our Queue class.
- Remove() removes and returns the oldest item in the Queue. This is different from Pop() which removed and returned the youngest item in the Queue.
- Provide a ShowQueue() method that displays all the items in the Queue from oldest to youngest.
- Instead of one Node pointer member, top, you'll need two Node pointer members, and neither should be called top (since top is not meaningful in a Queue). Examples are head/tail, front/back, oldest/youngest, etc. Select two names and use them accordingly.
Once you have written these two classes, write a simple test main() just like I did in the modules - show a run that displays some (generic node)s. Test the ShowQueue() method and also build a simple loop in your main() to remove and display nodes as they are removed. Compare the output of these two techniques -- they should be identical. You will not hand this in. It is just for your use in developing the full program.
Add() and Remove() will be slightly more complicated than Push() and Pop() because you have two pointers, front and back (or head and tail, or whatever you call them) to manage. This may take some time and debugging. Test it carefully. Even after you get it to work, you may find that it still needs debugging later, since your "(generic node)" screen results won't tell you if things are coming off in the correct order. You won't know that until you have real data in your Nodes. That's the next part.