Queues

Description

• FIFO
• Perfect line
• Useful in many data management situations

Queue ADT

• offer(E e) - Adds an item to the end queue
• E peek() - Returns, but does not remove an item from the front of the queue
• E poll() - Returns and removes an item from the front of the queue
• Java's Queue

Array Implementation

• Keep track of two pointers, front and end
• Set front and end initially to 0
• On offer, insert at end, and increment end
• On poll, return front, and increment front
• Allow both front and end to wrap around array (use modulus)

In-lab exercise

• Show how you can use two stacks to create a queue
• Show how you can use two queues to create a stack