CSC151.02 2003F, Class 55: Queues

Admin:
* Please show up and fill out evaluations tomorrow.
* I'll distribute grades tomorrow.
* Food!
  * Lunchmeat, Cheese, Lettuce/Tomatoes, Croissants in SciDiv Office
  * Blue Drinks, Clementines, and Candy in here

Overview:
* What is a stack?
* Questions on previous lab?
* About queues
* Lab

What is a stack?
* A Scheme thingy
* An Abstract Data Type
* An encapsulated way to store information
* The three P's: Push, Pop, Peek
  * Add something
  * Get something
  * See what you might get
* Policy: The thing you get with pop is the thing most recently pushed (that's still there).
  + LIFO: Last in, first out

Questions from the last lab?
* How to you write match-tags?
* See matchtags.scm

What is a Queue?
* A lot like a stack, except that it implements the FIFO policy.

Try lab for fifteen minutes.