CSC151.02 2016S, Class 46: Analyzing Procedures

Overview

Preliminaries

New partners!
I will continue to bring you food (or food-like substances) until I am caught up on grading.
- Today: Cookies!
Reminder: 161 is an awesome course.
- I'm sorry that you have not gotten enough feedback on whether you've been doing well. I think most of you can tell.
- Talk to me if you'd like my feedback on whether I think you're ready.
I should have comments on proposals by Friday.

Office hours this week
- See http://rebelsky.youcanbook.me.
- Ask me about other available times.
Tutor hours
- Sunday, 3-5 p.m.
- Sunday-Thursday, 7-10 p.m.
Review Sessions
- Wednesday at 8pm in CS commons with Sarah
- Thursday at 10 am with SamR
- Thursday at 8pm in CS commons with Kumar

Reading for Wednesday: Association Lists
Lab Writeup: Assorted questions (see end of eboard)
- Send email titled CSC 151 Lab Writeup 46 (Your Names)
- Do not include the underscores.
- Send to CSC151-02-grader@grinnell.edu
- Due before class on Friday.
Projects due NEXT TUESDAY.
Quiz Friday.

Send your reports to rebelsky@grinnell.edu with subject "CSC 151 Extra Credit". (Do not include the quotation marks.)
Send opportunities to me before class with subject "CSC 151 EXTRA CREDIT OPPORTUNITY!"

Open Listening Session, Tuesday, April 26, 6:00 p.m. - 7:00 pm, JRC 209
Scholars' Convocation: Dutch Global Horizons, Thursday, April 28, 11 am, JRC 101
Damon Williams: Bigger Than The Cops, April 28, 4pm or 5:15 pm

Social Dance Workshop Tuesdays 7:00-8:00 in Bucksbaum Dance Studio
Post-break ExCo on British Politics Wednesdays at 8:00 in JRC 203.
Just show up; you don't need to sign up.
Pun club Saturdays at 4pm in Younker
Electronic Potpourri on KDIC Fridays at Five
Space Odyssey KDIC Fridays at Six
Bollywood, Fridays, 7:30-8:30, Younker
Effective Altruism club, 2:30-3:30 Sundays in JRC 226.

Third year students, design a logo or something for a vinyl sticker.
Gift card to PC!

Should we write separate helper procedures on the project?

Please! It makes it easier for me to read. It makes it easier for you to experiment.

How upset will you be if we write a cond with 999 different options?

I'll be sad rather than mad.

How can I break an integer into a list?

One somewhat silly way

    (map (r-s - (char->integer #\0)) (map char->integer (string->list (number->string num))))

But math is your friend

    (list (quotient num 100) (quotient (remainder num 100) 10) (remainder num 10))

What if I want all sorts of numbers?

    (list (remainder num 5) (remainder num 7) (remainder num 11)
          (remainder num 13))

The lab makes much more sense if you've done the reading.

For list-reverse-2, make sure that you count calls to the kernel proc.

Remember! When you are counting calls to cons and company, you'll need to count the calls within append.

Writeup:

How many calls to cons do you expect when you use list-reverse-1 to reverse a list of N values?
(You should give a formula in terms of N.)
How many calls to cons do you expect when you use list-reverse-2 to reverse a list of N values? (You should give a formula in terms of N.)
What do you take as the primary "morals" of this lab?