CSC151.02, Class 32: Input and Output in Scheme

Admin
* Exam distributed.  Bring questions soon!
* Reading: Files in Scheme.
* In your extra time (ha ha ha), work on the vectors lab.
* Sam needs to return a lab writeup (hint hint hint).

Overview:
* Short reflection: Why did we get different animal results?
* Interacting with computer programs
* Lab
* Reflection

Short reflection completed.

Ways of interacting with programs
* The "prompt" model: You start the program and it prompts you for info.
* The "user-centric" model: You start the program and then tell it what to do (from a limited selection of options).
* DrScheme in general seems to be more user centric.
* How do you interact with the Scheme programs (or procedures) you write?
  * You write a procedure call.
  * Scheme chugs away and gives you a result.

Scheme provides access to the prompt model through three key procedures:
* (display value) - Prints a prompt
* (newline) - Print a newline (useful in results)
* (read) - Get a value from the user

Do the lab.