CSC 151.01, Class 39: Presentation prep

Overview

• Preliminaries
  • Notes and news
  • Upcoming work
  • Extra credit
  • Questions
• Quiz
• Presentation format
• Preparation time

Preliminaries

News / Etc.

• Sit with project teams.
• I will provide food for presentations on Monday. What would you like?
  • OJ
  • Fruit
  • Cheese and crackers
  • Graham crackers
  • Donut holes

Upcoming work

• Materials for presentations due Sunday at 7pm.
  • We’ll talk about the materials.
  • I do need time to put things together.
• Exam 4
  • Prologue due TONIGHT. Please don’t forget.
  • Exams due Tuesday at 10:30 p.m..
  • Cover sheets due Wednesday.
  • Epilogues due Wednesday.

Extra credit (Academic/Artistic)

• CLS Public Engagement in Science Symposium TODAY
  • Up Goer Five Challenge Poster Display May 4, 10 a.m. – 5 p.m., Bucksbaum Rotunda
  • Poster Reception May 4, 3 p.m., Bucksbaum Rotunda
  • “Our Journeys: From (Star Wars) Grinnell to Minute Physics & Minute Earth” Alex ’11 and Henry ’09 Reich May 4, 4 p.m., Faulconer Gallery

Extra credit (Peer)

• Grinnellian this Saturday, May 5 on Commencement Stage. “No” plays around 5pm. Jay Beard plays at 3pmish.

Extra credit (Recurring peer)

• Listen to KDIC Wednesdays at 6pm - Witty banter with other personalities and/or co-host. Also Indian, Arabic, and Farsi music.
  (Up to two units of extra credit.)
• Listen to KDIC Thursday at 7pm - Classic Rock. (60’s and 70’s)
• Peer editing with SS. Talk to SS about the details. Make your English Lit more literate.

Extra credit (Misc)

Other good things

• Waltz (at Country Club so that you can feel sufficiently upper-crust) Shuttles from JRC.
• Vocal recitals Friday.
• (Lots of other music stuff, too.)

Potentially less-good things

• RHPS
• Alice
• Pre-Waltz parties (?)

Friday PSA

• Moderation
• The bubble is contracting
• Consent is essential

Quiz 12

• I saw the most issues with the binary search problem.
• lower: 0, upper: 28, middle: 14, value: “Leo”, observation “Titus comes after Leo”
• lower: 15, upper: 28, middle: 21, value: Sam”, observation: “Titus appears after Sam”
  • We know Titus is not at 14, so why include it?
• lower: 22, upper: 28, middle: 25, value: “Violet”, observation: “Titus should appear before Violet”
• lower: 22, upper: 24, middle: 23, value: “Tess”, observation: “Titus should appear after Tess
• lower: 24, upper: 24, middle: 24, value: “Urkle”, observation: “Titus should appear before Urkle”
• lower: 24, upper: 23, WHOOPS! That describes an empty range.

Notes

• Issue one: Once you see that the value you are looking at is not in the middle, you should not include that index in the recursive call.
• Issue two: There are two reasons to stop:
  • You find the value you’re looking for.
  • The range becomes empty (lower exceeds upper)
• There was some correlation between forgetting to exclude the middle element and beign unsure as to when to stop.

Questions

I have no idea how to go about the second problem with the trees.

• That’s not a question.
• At least for the “straightforward” solution, you need to use direct recursion and “trust the magic recursion fairy”
  • Recurse on the left subtree
  • Recurse on the right subtree
  • Look at the root value
  • Combine!

What should we count on problem 6?

• Calls to car, cdr, cons, and null?

I have little idea as to how to work on problem 4

• There are three parameters. Figure out their types based on context.
• Run it “by hand” on a simple input, sketching out what happens.
• Either do the wonderful “expand code” approach that we used for sum or build a table like we do for tail-recursive procedures or both.

How do we show that our file-append solution works?

• I’d suggest something like the following.

> (file->lines file1)
("This" "is" "a" "file")
> (file->lines file2)
("This" "is" "not" "a" "fly")
> (merge-files file1 file2 result)
> (file->lines result)
("This" "is" "a" "file" "This" "is" "not" "a "fly")

Quiz

Sadness! It’s our last quiz.

Presentation format

• 2-3 minutes of talk
• 2-3 minutes of questions (and answers, we hope)
• Format
  • Option 1: Use Powerpoints (or equivalent). Send me Powerpoints or share Google slides or ….
  • Option 2: Live demo with talking. Send me code and data.
  • Option 3: Board talk (with optional handout).
• Suggested content
  • Who you are
  • Your goals
  • Your data (showing a sample line may be good)
  • What you accomplished
    • Perhaps: Data transformations
    • Perhaps: Code
    • Perhaps: Output
    • Perhaps: Analysis
• Don’t forget to cite sources, including not only your pages but also images you grab.

Questions

• Do we all have to talk? No, but you should all contribute to the design of the presentation.

Preparation time

• I realize that 45 minutes isn’t quite enough time to make a presentation, but I hope it moves you forward appropriately.