CSC 160 Fall 2008 - Homework 2
Assigned Sept 8, due MONDAY Sept 22

Read Chapters 3-4 of Dr. Bloch's textbook.

Read this Definition of a Program.

Read this article on Pair Programming.

Do the following exercises from the textbook in DrScheme:
  • Exercise 2.1.3:
    Store a picture in a variable. Then define another variable named two-copies whose value is two copies of that picture, side by side, by using the previous variable. Then define a third variable named six-copies whose value is a six-pack of the picture, 2 wide by 3 high, by using two-copies.
  • Exercise 3.1.3
          a) Define a variable named solid-green-box whose value is a solid green rectangle. Use a width of 10 and a height of 20.
          b) Define a variable named outline-blue-box which is what it sounds like. Use a width of 10 and a height of 20.
          For parts c-g, use only the variable names. Do not use the pictures of the rectangles or the expressions using the rectangle operation, or only half credit will be given.
          c) Write an expression to put the solid box above the outline of a box.
          d) Write an expression to put the solid box on top of (not above) the outline of a box.
          e) Write an expression to put the outline of a box on top of (not above) the solid box.
          f) Write a full sentence describing why the results of d) and e) different. Make sure you put a semicolon at the start of that line to comment it out.
          g) Create a two by two checkerboard where the upper left and bottom right corners have the solid box, and the upper right and lower left corners have the outline of a box.
  • Exercise 3.2.1:
    Write the function contracts for ellipse and circle only. For each argument, include its data type then describe what that argument is in parentheses. (Make sure this exercise is commented out, as discussed in Section 3.3). Note: The contract for triangle will be given in class, so it is omitted from this exercise.
  • Exercise 3.4.4:
    Hint: A circle's width and height are each twice the radius.
  • Exercise 3.4.5:
    Note: For full credit, you must write a single expression to do this. However, that single expression will have subexpressions within it.
  • Exercise 3.5.2:
    Note: You may use any picture of a person's face for this question. It does not have to be the picture in the textbook.


    • Do the following box diagram exercises from the textbook on paper:
  • 2.4.2: Draw a box diagram to prove that (rotate-cw calendar) is a legal expression. Assume that calendar is already defined.
  • 2.4.3: Draw a box diagram for each of the three expressions in your solution to Exercise 2.1.3 to prove they are all legal expressions.
  • 3.7.2: Draw a box diagram to prove that (define tri (triangle 15 "solid" "orange")) is a legal expression. Assuming that tri is not already defined.

    Submitting your Assignment
    For this assignment, and all future assignments, your DrScheme files (Definitions and Interactions) may not be submitted on paper.

    Please submit your Definitions Pane and Interactions Pane through Moodle. Be sure to include your first and last name as a comment in the first line of your Defintions and Interactions panes.

    Please submit your Box Diagrams on paper in class by the due date.

    The file name for the Definitions Pane needs to be "hw2[LastName]Def.scm" where:
  • [LastName] is replaced with your last name.
  • For example, if I were submitting this assignment, I would name the file "hw2WittensteinDef.scm".

    Similarly, the file name for the Interactions Pane needs to be "hw2[LastName]Int.scm".

    Please let me know if this is not clear or if you are unsure exactly what filename to use. Part of your grade is using the correct filenames.


    GRADING
    Question Point Value
    2.1.3 10
    2.4.2 5
    2.4.3 15
    3.1.3 35
    3.2.1 10
    3.4.4 10
    3.4.5 10
    3.5.2 10
    3.7.2 10
    Filenames 5
    Total 120




    Last Modified: 9/21/08