CSC 151.01, Class 41: Project presentations

Overview

• Preliminaries
  • Notes and news
  • Upcoming work
  • Extra credit
  • Questions
• About the presentations
• Lightning presentations

News / Etc.

• I expect you all to attend class on Friday.

Upcoming work

• Exam 4
  • Exam due Thursday
  • Cover sheets due Friday
  • Epilogues due Friday
• Optional final during finals week (Wed 2pm, Thu 9am, or Fri 9am).

Extra credit (Academic/Artistic)

• CS Extras Thursday: Summer opportunities in CS. 4:15 p.m. in Science 3821. Food at 4:00 in the CS Commons.
  • Handouts available for those who can’t make it.

Extra credit (Peer)

• Musical: Next to Normal Friday at 7:30, Saturday and Sunday at 2:30. Tickets no longer at box office. Show up early (Roberts).

Extra credit (Misc)

Other good things

• Stay healthy and sane during week 14.

Questions

Any more hints on problem 2?

“Trust the magic recursion fairy.” You’ve determined that lst is a pair. You tally the rest with (nested-list-tall (cdr lst) pred?). What do you do next?

Any hints on problem 4?

Use the debugger.

Follow the steps through by hand.

Can I have a more comprehensive test suite for problem 4?

Sure.

(check-equal? (next-larger 1/2 (vector 1 2 3 4 5 6)) 1)
(check-equal? (next-larger 1 (vector 1 2 3 4 5 6)) 2)
(check-equal? (next-larger 3/2 (vector 1 2 3 4 5 6)) 2)
(check-equal? (next-larger 2 (vector 1 2 3 4 5 6)) 3)
(check-equal? (next-larger 5/2 (vector 1 2 3 4 5 6)) 3)
(check-equal? (next-larger 3 (vector 1 2 3 4 5 6)) 4)
(check-equal? (next-larger 7/2 (vector 1 2 3 4 5 6)) 4)
(check-equal? (next-larger 4 (vector 1 2 3 4 5 6)) 5)
(check-equal? (next-larger 9/2 (vector 1 2 3 4 5 6)) 5)
(check-equal? (next-larger 5 (vector 1 2 3 4 5 6)) 6)
(check-equal? (next-larger 11/2 (vector 1 2 3 4 5 6)) 6)
(check-equal? (next-larger 6 (vector 1 2 3 4 5 6)) #f)
(check-equal? (next-larger 13/2 (vector 1 2 3 4 5 6)) #f)

Can’t you write something more concise?

Yes. But I thought this was clearer.

Does nested-list-tally? have to work correctly if the predicate is list?.

No. It doesn’t have to work for pair? or null? either.

How should I get started on problem 3?

Find out how big the result vector should be. (recursive helper)

Make a vector of that size.

Copy you things over (recursive helper). (vector-set newvec newpos (vector-ref vec pos)).

Do you have hints on problem 6?

Read the list of topics. That should tell you what vss! does and give you a clue to the parameters.

Look at how vss! calls ioe.

Sam remembers the names of these two procedures. That may suggest that they have something to do with what the procedures do.

Make sure to use unordered vectors when you try vss! and ioe.

Any hints on problem 5?

Problem 5 is incredibly straightforward.

Problem 5e: The helper is the way to go. When you first call it, you’ll call (helper tree null).

On 5d, you’ve thought a bit about ordering.

About the presentations

• I’ll use the clock.
• I realize that there will be some transition time.
• Do your best!
• Plan to take questions (and to ask questions).

Lightning presentations

You can volunteer or our mentors will choose