• Sit wherever you feel like, including with Wednesday's partner.

Overview

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

Preliminaries

Admin

• Office hours today and next week
  • Normal (MThF 1:45-3:15; walking 1:15-1:45)
• Reminder: I put useful information in the "CSC 151.01" emails. Please try to read them (or at least skim them).
• Welcome to our visiting prospective student!
• Please don't ask the tutors for any help on exam 2 (or any exam).
• We are having network issues. Try to get Gimp/DrRacket set up before the quiz.
• I love that we currently have a wireless network named GrinnellCollegeBOT.
• This week's PSA. It's 10/10. Remember that you do not need to drink; many students choose not to. Reflect in advance on choices you might make this weekend. If you do choose to drink, please drink responsibly. And remember that it is unlikely that you or your partner can give or receive consent if you are drunk.

Upcoming Work

• Writeup: Problems 4 and 5 (due Monday): http://bit.ly/151-2014F-w25
• Exam 2 due Tuesday.
  • Optional prologue due 10:30 p.m. tonight.
• Reading for Monday:
  • Recursion with Helper Procedures

Cool Things Coming to Campus

• Two versions of Anna Christie!
• Live Streaming of Verdi's Macbeth, Saturday at 11:55 a.m.

Extra Credit Opportunities

Academic

• CS Table Today: Evolutionary Art (readings in the hallway outside my office)
• BCC Faculty Chat, Tuesday, October 14, 7pm

Peer Support

• Football (Saturday at 1pm)
• Swimming October 18: Alumni Weekend
• Karan's radio show 11pm Thursday nights on KDIC
• Evan's radio show 5pm Friday nights on KDIC
• Donna's radio show Sunday midnight on KDIC
• The College's version of Anna Christie, Oct. 9-12 (SB plays Marthy)
• Men's Tennis (???)
• Women's Tennis (???)

Miscellaneous

• Fill in the Grinnell College Web Survey at http://bit.ly/1ncPO5V
  • The folks who've filled it in report that it is more fun than normal surveys.

Exam Advice

Some good comments on doing well on the exam (from exam 1 epilogues and exam 2 prologues).

• Split up the work more evenly.
• Check over the work before submitting.
• Divide into small sections so I'm more likely to get work done, so it doesn't look so intimidating.
• Email Sam. Visit Sam. Sam says: You can ask me anything. My answer may be "Sorry, I can't tell you that." But you can ask.
• Once stuck, move on and come back later
• Refer back to notes and readings makes it easier.
• Read all of the question (I didn't do that last time and missed a part).
• If I find myself particularly stuck on a certain problem, I should move on or take a break. I found that trying to work for too long on a frustrating part just led to more frustration and less clarity.
• Look at Sam's notes on exam 1 for ideas.
• Don't freak out when something isn't working. Often, it's just a paren of syntax issue, and you can ask Sam about those.
• It isn't something I should do differently, but I found that doing the problems in my own order (e.g., I started with 7) made the test seem less daunting and working through the problems I was most comfortable with first gave me a little boost of confidence that I needed to do the more challenging problems.
• Look at the topics of each problem as they often contain hints as to how to approach the problem.

Questions

Can we use car and cdr on the exam?

Yes, but I don't think they'll be useful.

Can we use recursion on the exam?

Yes, except on problems in which it is explicitly forbidden, such as problem 5. Recursion will also lead to a longer solution to problem 4 than we'd like.

The exam does not need recursion.

Quiz

Lab

Is it really okay that (product null) is 1?

Yes. We were okay that (sum null) is 0. 0 is the additive identity and 1 is the multiplicative identity.

Can I make the base case test in product something like "if there is one element in the list?"

Yes. You'd use the following pattern

    (if (null? (cdr numbers))
        CONSEQUENT
        ALTERNATE)

Reflection