CSC151.01 2015F, Class 39: Trees (well, really vectors)

Overview

Preliminaries

Continue partners!
We will finish the Vectors lab today and do the Trees lab another day.
Review sessions this week:
- Wednesday, 8pm (Caleb)
- Thursday, 10am (SamR)
- Thursday, 8pm (Erin)
Office hours this week and next: MWF 8:30-9:00, 11:00-11:45, 1:00-2:00; Tu 1:00-2:00.
I am home sick today. Because of that, you have an extension on the exam until Thurday night. When I have a chance, I will answer questions sent via email.
When asking for help, it's important that you choose your procedure and variable names well, and that you document your procedures a bit. Neither I nor the tutors appreciate the overhead of dealing with something like
```
(define fiddledidee
  (lambda (a b)
    (let kernel ([thinga ""]
                 [mabob (cons a b)])
      ...)))
```
I've gotten reinforcement that Problem 5 is really easy once you think it through (of course, the statement was preceded by "Sam, you are evil").
So, to reiterate the Q&A section:
- for-each typically takes a procedure and a list as parameters.
- Think about the form of the list that you will give as an argument to for-each in this problem.
- Think about what type of value the procedure you give as an argument to for-each will take as its input.
- For example, what do you know about x in (for-each (lambda (x) ...) (iota 10))?

Readings for Wednesday:
Elements and Principles of Two-Dimensional Design and About the Project
Today's Lab writeup (due before class Friday)
- Email to grader-151-01@cs.grinnell.edu
- Subject: CSC 151 Lab Writeup Class 38 (Your Names)
- Exercises:

Pals of PALS, pals@grinnell.edu, normally Saturday at 7:45 am (breakfast included; felines only), and Mondays at 4:45. Requires sign up in advance. MORE HELP NEEDED!
Socrates Cafe', Saturdays, Younker, 2pm.
Pun Club, Saturdays, 4pm, Way over Younker.

Finish the vetor lab.

If you have time, start the tree lab. We will continue it another day.