CS 5010 F '09
Pair Programming
The Recipes
The Style
Set 1
Set 2
Set 3
Set 4
Set 5
Set 6
Set 7
Set 8
Set 9
Set 10
Set 11
Set 12

Problem Set 12


Due date: 12/09


The purpose of this problem set is to understand the mechanisms of abstractions in an object-oriented programming language, especially (abstract) classes, inheritance, and overriding.


HtDC: All problems in part iv. Ignore all problems that ask you to draw things.

Required Problems:

Note: You must use the Module language level in DrScheme and you must use the language #lang scheme.

  1. "Edit" your solution of problem 10.1/11.1. Then add a class for representing subtraction expressions, which have exactly two sub-expressions.

  2. Turn your solution of 10.2/11.2 into a complete class-oriented solution, using the base class world% from the class-universe.ss teachpack. The teachpack exports four items: world<%>, world%, place-image, and empty-scene. The first two describe a base class for creating world programs. The latter two are from universe.ss.

    Then "edit" your solution of problem 10.2/11.2.

last updated on Wed Dec 2 17:58:10 EST 2009generated with PLT Scheme