CSC 160
Homework 6

Assigned 22 Oct, due 3 Nov

Links to textbook

• Chapter 15 of the textbook
• Worked Exercises from my textbook

Problems

• Do but don't turn in Exercise 15.1.1 (practice with posns)
• Do but don't turn in Exercise 15.3.2 (above-diagonal?)
• Exercise 15.3.4 (coordinate-difference)
• Exercise 15.3.5 (distance)
• Exercise 15.3.6 (posn=?)
• Exercise 15.3.7 (distance-to-origin)
• Exercise 15.5.2 (swap-x-y)
• Exercise 15.5.3 (scale-posn)
• Exercise 15.5.4 (add-posns)
• Exercise 15.5.5 (sub-posns)
• Exercise 15.5.7 (choose-posn)
• Exercise 15.6.2 (random jumping dot animation)
  Hint: you could do this with an image as the model, but the next exercise is built on this one, and it requires a posn as the model. So use a posn as your model!
• Exercise 15.6.3 (reflex video-game animation)
• Choose one or more ("more" is extra credit) of
  • Exercise 15.6.4 (add "q" key to animation)
  • Exercise 15.6.5 (add "jump to mouse location" to animation)
  • Exercise 15.6.6 (dots colored red or green depending on coordinates)
  • Exercise 15.6.7 (Brownian motion)
  • Exercise 15.6.8 (wrapping around edges of screen)

What to turn in and how

All of the problems are programming problems, and many of them depend on one another, so it's probably a good idea to write them all in one Definitions pane. But three (or more) of them are animations, so I recommend commenting out the (run-animation...) line for all but one of the animations. If I want to see other ones run, I can un-comment it myself.

Also turn in a log of how many errors of different kinds you encountered in the assignment, with brief comments describing each one ("mismatched parentheses" is self-explanatory, but more complex errors might need more description). Note that "errors" means not only error messages from DrScheme, but also wrong answers. You may do this using the PSP forms, or simply by keeping track in a text file or on paper and turning it in.

General advice

For every function you write, be sure to follow the design recipe. If a particular animation requires writing two or three functions, that means go through all the steps of the design recipe two or three times for that animation.

Be sure to choose meaningful names for functions and parameters, and watch for opportunities to re-use functions you (or the textbook) have already written.

This assignment is to be done in pairs, using the ideas from the "kindergarten" article. Choose a partner ASAP and schedule time to work together on the assignment. When you're finished, turn in one assignment with both names on it. You'll have a different partner for homework 6, so if you don't get along with this partner, remember it's only for a week.

Grading standards

Error log:       /20
(I'm not grading on how many or how few errors you encountered, only on whether you recorded them correctly.)

I sha'n't actually grade all the problems; consider the others "practice". For each function I grade, see the table below, which has columns for each step in the design recipe. You won't turn in a separate skeleton, inventory, and definition, but rather write a skeleton, then add an inventory, then add a body to turn it into a complete definition. However, if you don't get the definition working, comment it out and you'll still get partial credit for a correct skeleton and/or inventory.

General skills:

Total:         /???