• New partners!

Overview

• Preliminaries.
  • Admin.
  • Upcoming Work.
  • Extra Credit.
  • Questions.
• Lab.

Preliminaries

Admin

• Congratulations to MN! (No, not to EG's home state.)
• A moment of silence for the peoples of Beirut and Paris, and to the many others who will be affected by the events there and the responses to those events.
• Exams returned at the end of class.
• Review sessions this week:
  • Monday, 8pm (Zachary)
  • Wednesday, 8pm (Caleb)
  • Thursday, 10am (SamR)
  • Thursday, 8pm (Erin)

Upcoming Work

• Project Proposal: TONIGHT at 10:30 p.m.
• Project Pictures: Tuesday at 10:00 a.m.
• Projects: Next Tuesday at 10:00 a.m.
• Reading for Tuesday: Higher-Order Procedures
• Today's Lab writeup (due before class Wednesday)
  • Email to grader-151-01@cs.grinnell.edu
  • Subject: CSC 151 Lab Writeup Class 42 (Your Names)
  • Exercises: Exercise 4

Extra Credit Opportunities

• If possible, send me these in advance.

Academic

• Any visit to the current show in the Faulconer gallery.
• Learning Deconstructed Workshop Series, Tuesdays at 11 in JRC 209.
• CS Table Tuesday: Social Media and Emergency Response
• Scholars' Convocation Thursday: Cosmic Secrets: Soviet Space Exploration, Censorship, and the Cold War.
• Metropolitan Opera Simulcast, November 21, 11:30 a.m. Lulu by Berg, Harris Cinema.

Peer Support

• Translations (a play). 7:30 p.m. Thursday through Saturday, 2:00 p.m. Sunday. Tickets at the Box Office.

Regular Peer Support

• 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.

Upcoming Peer Support

• Women's Basketball vs. Beloit, Nov. 28 at 3:00 p.m.
• Women's Basketball vs. St. Norbert, Dec. 5 at 3:00 p.m.
• One-act Festival Dec. 5 & 6.
• Grinnell Singers, Dec. 6
• Women's Basketball vs. Carroll, Dec. 12 at 3:00 p.m.

Questions

Will you penalize me for missing class next Wednesday because the idiotic College thinks that noon buses are a good idea on a day when we have classes?

No.

Will you still teach something that day that I'm expected to know?

Yes. Do the lab on your own.

I've discovered that you can seed the random number generator. If you give it the same seed, it gives you the same sequence of numbers. Can I use that idea?

I suppose so. But you should still have something other than the randomly generated numbers that is computed based on N and guarantees 1000 different images.

Do you have a good sample proposal?

No.

How detailed should the initial technical statement be?

It can be pretty high-level. Make sure you indicate the three different techniques and how you are using them. Make sure to argue for 1000 different images using something other than "predictably random".

Lab

Helper recursion will not work well for sum. Use direct recursion, using the pattern you've seen.

number-tree-largest will need a variant of tree recursion. (You'll need to think about different base cases and different recursive cases.)

• There are probably two base cases
  • The empty tree is an error
  • ...
• There are probably three recursive cases * * *

Make sure to check (number-tree-largest (leaf -3)), which should be -3.

number-tree? can be written elegantly using and and or.

Writeup: Exercise 4.