---
title: Eboard 39  Presentation prep
number: 39
section: eboards
held: 2018-05-04
link: true
---
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](../exams/exam04) 
    * 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.