Stacks and Queues

Fundemental data types

Value: collection of objects.
Operations: insert, remove, iterate, test if empty.
Intent is clear when we insert.
Which item do we remove?
- Stack : Last In First Out - LIFO
- Queue: First in First Out - FIFO

Bag

Adding items to a collection and iterating ( Order does not matter )

Implementation is similar to stack / queue without pop / dequeue respectively