Class 55: Queues

Held: Thursday, 11 December 2003

Summary: Today we consider another important data structure, the queue.

Related Pages:

• EBoard.
• queues.scm.
• Reading on Queues.
• Lab on Queues.

Notes:

• Tomorrow you get the joy of filling out class evaluations.
• Do not consider today's food a bribe.

Overview:

• Review of stacks.
• Quick introduction to queues.
• Lab.

Review of Stacks

• A simplified mechanism for storing information.
• Basic operations: push (add an item) and pop (give me an item).
• Other operations: create a new stack, peek at the next item, compute the size, determine if empty.
• Implementation: use a vector that contains a list.
• Questions on the lab?

Queues

• Like stacks in that the basic operations are add an item and give me an item.
• Unlike stacks in that the item returned is the least recently added rather than the most recently added.
• Often harder to implement than stacks.
• Uses different names for the key operations (enqueue, dequeue, and front).

Lab

• Any questions?
• Do the lab.
• Be prepared to reflect.