CSC151.01 2006S, Class 22: Discussion of Exam 1

Admin:
* EC
  * Tuesday Extra: Installing Linux.  1:00 p.m. 2424.  Snacks at 12:45
* Wednesday and Friday this week: A Short Project.
* Reading for Tuesday: Randomness and Simulations

Overview:
* Notes on Homework 8
* Notes on exam 1.
* Time to work on the Local Procedures Lab.

/Notes on Homework 8/

* (intersect (list 'a 'b 'c) (list 'd 'd 'b 'a))
  * Can be (a b)
  * Can be (b a)
  * How do we write a test?
    (test! (member? 'a (intersect ...)) #t)
    (test! (member? 'b (intersect ...)) #t)
    (test! (length (intersect ...)) 2)
  * Use test-permutation!
    (test-permutation! (intersect ...) (list 'a 'b))
* Should 5 and 5.0 be the same for the purposes of this homework?
  * No, they are not the same in general.  Exact numbers should not be
    the same as inexact numbers.
  * IRRELEVANT: The assignment says "lists of symbols"
* Do we need to check preconditions?
  * Nah.

/Notes on Exam 1/

* Policy: I return your exams after discussing them.
* If you did poorly, make an appointment with me
  * Think about Tutors
  * Think about regular appointment with Sam

* Big picture issues:
  * Use whitespace, please
  * Theadventofaspacemadeitmucheasiertoreadsequencesofwords
  * Lng g w lrnd t s vwls
* Use tab to format (select all, hit tab)

//Problem 1: type-of//

* A fancy way to write
  * What types have you learned, and what are the predicates for those types?
  * What is the "hierarchy" of numbers?
* Danger of test-driven development