Overview

• Preliminaries.

  • Admin.
  • Questions.

• Debriefing from previous class.

• Students discuss programming techniques.

Preliminaries

Admin

• Enjoy Happy Exciting Liberal Learning Week (Aka Well week)
• Candy and Fruit!
• Study break tonight 8-10. Smoothies! (May run out, so get there early.)
  • Yes, 151 students are welcome to attend CS study breaks!
• Upcoming extra credit opportunities:
  • CS Extras Thursday at 4:30: Mediascripting
  • Math/Stats Talk Today at 4:15
  • Math/Stats Talk Tomorrow at 4:15
  • CS Table Friday: TBD.
• Handouts from Sam's talk last week http://www.cs.grinnell.edu/~rebelsky/Department/cs-summer.html

Questions on Exam 3

On 4b, you ask us to summarize what we learn. How much do you want?

It should be pretty obvious why Sam gets frustrated by code like this. A sentence should suffice.

I can't get recursion to work with a named let

(define sum (lambda (lst) (let kernel ([sum-so-far 0] [remaining lst]) (if (null? remaining) sum-so-far (kernel (+ sum-so-far (car remaining)) (cdr remaining))))))

Does that let me change values?

Kind of

Why did you give us my-length?

So that we can count what's really going on, and see why Sam is annoyed.

And is it how length is normally implemented?

Yes

Should we provide the modified my-length?

Yes

Can we use your list for the vector-assoc problem?

Yes

For Problem 5 (Steganography), what is your grading plan?

• One lambda and correct code: Full credit
• Two lambdas and correct code: Less than full credit
• Three lambdas and correct code: Much less than full credit
• Only lambdas and parentheses (AND CORRECT): Double credit
• Zero lambdas and correct code: More than full credit
• Zero lambdas and ugly code: TBD

_Don't we always need at least one lambda?)

No

(define increment (l-s + 1))

Can you clarify due stuff?

If you email me the exam by 10:30 p.m. CT on Monday, 9 December 2013 and hand me a paper copy by 1:15 p.m. on Tuesday, 10 December 2013, you get two more points on the exam. So, if you had 125 points, you now have 127.

If you email me the exam by 10:30 p.m. CT on Tuesday, 10 December 2013 and hand me a paper copy by 1:15 p.m. on Wednesday, 11 Decmeber 2013, you get your normal score on the exam.

If you fail to achieve either of those cases, and you haven't arranged an alternative with me, your grade is likely to be significantly lower.

Question that is so confusing that Sam can't even write it down

Let's talk one on one.

Can we resubmit our electronic version?

It depends on whether I've started grading it or not. Once I've started grading, your copy, you may not give me a new copy.

What should we do if there's another final at the same time as your final?

Talk to me about rescheduling.

Debriefing from previous class

Students discuss programming techniques