Held: Wednesday, 10 February 2016

Back to Outline 10 - Documenting Programs and Procedures. On to Outline 12 - Testing Your Procedures.

Summary

We consider sipmle textual interactive programs, programs that read input from the user and produce output.

Related Pages

• Reading: Simple Output in Scheme
• Reading: Simple Input in Scheme
• Lab: Input, Output, and Side Effects
• EBoard 11 (Source 11)

Overview

• Simple output in Scheme.
• Using output to trace program behavior.
• Reading lines of text with read-line.
• Reading Scheme values with read.
• Side effects.

Administrivia

• New partners!
• Please take a goldenrod card.
• I had hoped to shorten the pre-class administrivia today, but with the distribution of an exam, that's not possible.
• Apologies for the effects of the MathLAN downtime. (Yes, it affected me, too.)
• I've rearranged the schedule slightly, so you'll need to read over the documentation reading for Friday, as well as the normal Friday reading on testing.
• When you hit more than nine hours outside of class in a week (ten hours in an exam week), let me know how you are spending your time so that I can try to cut the workload.

Reminders

• Office hours: MTWF 10-11, Tu 1-2.
  • Sign up at http://rebelsky.youcanbook.me.
  • 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 Stupendous Sarah!
  • Thursday at 10am in this room with Sarcastic SamR!
  • Thursday at 8pm in the CS Commons with Amazing Alex.

Upcoming Work:

• Readings for Friday:
  • Documenting Your Procedures
  • Testing Your Procedures
• Assignment 3 due tomorrow night at 10:30 p.m. (optional, only positive effect on your grade)
• Exam 1
• Quiz Friday
  • Defining procedures with section
  • Procedures with lambda
  • Documentation
  • Order-of-evaluation
  • Simple output (particularly annotating procedures)
  • Some reading ("what does this code do?"), some writing ("write a procedure that ...")
• Lab Writeup: Exercise _
  • Send email titled CSC 151 Lab Writeup 11 (Your Names)
  • Do not include the underscores.
  • Send to CSC151-02-grader@grinnell.edu
  • Due before class on Monday.

Exam 1

• We'll take a few minutes to look over exam 1.
• Please pay particular attention to the policies.
• Please bring questions on Friday (and Monday, and Tuesday).

Extra Credit

• Send to rebelsky@grinnell.edu with subject "CSC 151 Extra Credit".

Academic

• This week's Rosenfield Symposium on Campaign Finance.
• This week's Carnival and Creativity series.
• CS Extras tomorrow: Q&A with alums.
• Convocation next week: Hilary Mason '00 on Data Science and Social Good.
• CS Extras next week: Hilary Mason on Fast Forward Labs.

Peer

• Track and Field February 13.
• Love Notes. If the $2 is a stretch, Sam will pay. Email JS the elder.
• Shanghai Express Saturday at 4:30 p.m. in JRC 101.

Regular Peer

• Social Dance Workshop Tuesdays 7:00-8:00 in Bucksbaum Dance Studio (starting next 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

No Extra Credit, But Still Good

• High School Large Group Speech Presentations Saturday at 6:30 p.m. at the high-school auditorium. Sam will reimburse you for the $5 entry fee (or give it to you in advance).

Output

• Use display to print values.
• Use newline to print a newline.

Using Output to Trace Program Behavior

• By inserting appropriate calls to display and newline, we can better see what our program does.

Input

• Read a line of text with read-line.
• Read the next Scheme value with read.
• Use these to write interactive programs.
• We'll revisit these again in the future as we learn more copmlicated forms of Scheme expressions.

Side Effects

• All of these procedures are procedures with side effects - in addition to returning a value (assuming they return a value) they also change the state of the environment.
• Procedures with side effects tend to complicate our understanding of programs and can sometimes lead to unexpected behavior.