CSC151.02 2016S, Class 09: Writing Your Own Procedures, Continued ================================================================= _Overview_ * Preliminaries. * Admin. * Upcoming Work. * Extra Credit. * Questions. * More about procedures. * Lab, continued. * Questions and reflection. Preliminaries ------------- ### Admin * Old partners! * Today's lab is a continuation from Friday's class. * Our graders sent back preliminary grades on your lab writeups. Those will generally be on a 0/1 scale (not submitted or significantly incorrect gets a 0; everything else gets a 1). * If you would like to be added to the CS Department's Mailing List for events, please send me email. * Quiz 2 returned. We need to talk about the last problem. * Prospie! ### Reminders * Office hours: MTWF 10-11, Tu 1-2. * Sign up at . * Also feel free to stop by when my door is open. * Or to email me for an appointment. * Tutor hours * Sunday, 3-5 p.m. * Sunday-Thursday, 7-10 p.m. * Weekly review sessions: * Wednesday at 8pm in the CS Commons with ? * Thursday at 10am in this room with SamR * Thursday at 8pm in the CS Commons with ? ### Upcoming Work: * Readings for Tuesday: * [Simple Output in Scheme](../readings/output-reading.html) * [Simple Input in Scheme](../readings/simple-input-reading.html) * [Assignment 3](../assignments/assignment.03.html) due tomorrow at 10:30 p.m. * Lab Writeup: Exercises 3 ab and 5 * Send email titled __CSC 151 Lab Writeup 9 (Your Names)__ * Do not include the underscores. * Send to * Due before class on Wednesday. ### Extra Credit * Send to with subject "CSC 151 Extra Credit". #### Academic * This week's Rosenfield Symposium on Campaign Finance * Monday, February 8, 4:15 p.m. in Bucksbaum 152, Miriam Langer enjoins you to "Do Your Work in Public" (part of the series "Digital in Public: Intellectual and Technical Skills for Making a Difference") * Monday, February 8, 7:30-9:00, JRC 101: The Complex Relation Between Alcohol and Sexual Assault * Noon Tuesday in the White PDR: Bowie, Mickey, and the NFL: Copyright in the 21st century (copies of the reading outside Sam's office) * 7:30 pm Tuesday in ARH 131 - Funding for unfunded internships * Thursday at 4:15 in 3821 - Life After Grinnell (for CS students) * Anything in next week's Carnival and Creativity series #### Peer * Track and Field February 13. * Love Notes. If the $2 is a stretch, Sam will pay. Email JS the elder. #### Regular Peer * Social Dance Workshop Tuesdays 7:00-8:00 in Bucksbaum Dance Studio (starting this week) * Pun club Saturdays at 4pm in Younker (max 2) * Socrates Cafe' Saturdays (max 2) email [socratescafe] to be added to the mailing list to hear about the top secret meeting location * Electronic Potpourri on KDIC Fridays at Five * Wednesday, 7:30, ARH 120, Environmental Movie ### No Extra Credit, But Still Good * High School Large Group Speech Presentations Saturday at 6:30 p.m. (I think) at the high-school auditorium. ### Quiz (define fave (irgb 250 0 42)) (define fave2 (irgb-lighter (irgb-darker fave))) (irgb-complement fave) * The way we express values is important, so "250/0/42" (that's for `(irgb->string fave)`. * `(irgb-complement fave)` does not change `fave`; it just computes a new color The last problem: Write a procedure that adds 32 to each component. Three possible strategies: * `lambda`. * `section`. * `compose`. We need to use compose. (define irgb-much-lighter (compose irgb-lighter irgb-lighter)) ; not allowed (define irgb-much-lighter (compose irgb-redder irgb-greener irgb-bluer)) (define irgb-much-lighter (compose irgb-complement irgb-darker irgb-darker irgb-complement)) Similar questions were in the mentor sessions and in the notes. (And no, we did not intend to give a particular advantage to those folks.) ### Questions _Can we write `define` in the middle of a procedure?_ > No. _Did you even look at what you wrote for problem 4?_ > I thought so. I'll fix it during class. _How much info should we provide when citing other groups?_ > Approximately: "I talked to Tulah's Two Taylors about problem 4 and they provided me with advice on it." _How should we cite code from the assignment?_ > I don't require you to cite code from assignments. > If you choose to cite such code, use something like "Taken from assignment 3 at ." > Or Curtsinger, C., Davis, J., Rebelsky, S. A., and Weinman, J. (2016). _Assignment 3: Color Transformations and Image Filters._ Grinnell College, Dept. of CS. Online document at , last modified 2016-02-01; visited yesterday. _How can we wrap around given that the remainder function doesn't take decimals?_ > Option 1: Round to the nearest integer. > Option 2: Use a more clever calculation. More about procedures --------------------- (define square (lambda (num) (* num num))) (define square (lambda (renn) (* renn renn))) (define square (lambda (color) (* color color))) Scheme doesn't care what you call your parameters! So choose a name that makes sense to your human reader. Be careful about what you name your parameters, as they can override existing names. (define square (lambda (*) (* * *))) (define square (lambda (+) (* + +))) Ugh. Lab, continued -------------- Writeup: 3 ab and 5 Questions and reflection ------------------------