CSC 171
Homework assignment 4

Fall, 1998

In class:

Rules:

• Do not change any of the code already in the file; merely add your own in the body of the writeC method.
• Do not use the setPosition or setHeading methods. Assume that fred is at position (1,1), facing EAST, before he is told to writeC.
• You must leave fred in the position shown above, in the bottom row, two squares to the right of the letter C, facing EAST. Again, do not use setPosition or setHeading to do this (but brushUp() and brushDown() are OK).
• Do not assume fred is already painting in the right color; he should set his color according to the letter_color parameter before painting anything.

Big deal, you say: betty knew how to draw a C two weeks ago. But watch this: open the CSC171_BuggleWorld.java file, find the run() method, and add just after fred.writeC(red); the additional statement fred.writeC(green);. If you've done everything according to the above rules, this one additional line should produce a second C, in green, properly positioned to the right of the first one.

To be done outside class:

Method in their Buggleness

Next, modify the program so that it writes "CSC171" with each letter in a different color. You should be able to do this by adding only a few lines to the run() method.

Fred is so excited by being able to spell the name of the course that he wants to be able to do it any time he likes. Write another method named CSC171 which writes "CSC171" with each letter in a different color.

Finally, let's give Fred more opportunity to practice his writing: we'll have him write "CSC171" along the bottom of the Buggle grid, then again sideways along the right-hand edge of the screen (moving up), again upside-down along the top of the grid, and one more time sideways along the left side, ending up where he started. Note that at each corner Fred will have to move a few squares and change directions before starting his next CSC171; this is a good opportunity for another method.

To be turned in:

Homework 4a: Fred's Excellent Adventure

Homework 4b: Enough with the Buggles, already; let's read a book

• allNovels, which returns true or false to indicate whether the stack consists entirely of Novels;
• containsANovel, which returns true or false to indicate whether the stack contains at least one Novel; and
• countNovels, which returns an int indicating how many Novels were in the stack.

What to turn in for BookPiles

1. A class diagram showing how all the classes you defined relate to one another (this may be drawn and turned in on paper, or turned in by email -- your choice).
2. A Java source file, BookPiles.java, containing definitions of the classes and a main program to test them. In particular, for each of the methods and constructors, you are to write
   1. A "contract" showing what kind of information the method or constructor expects to be given, and what kind of information it promises to produce (this should be in a Java comment at the beginning of the method)
   2. A list of several examples of how the method or constructor could be used, along with the "correct" answer you would expect the method or constructor to produce (also in a Java comment, just after the contract)
   3. The "head" of the method or constructor (corresponding to

       boolean onlyOnions () { 

      in the book)
   4. The "body" of the method or constructor
   5. Several lines in the main program that actually try the method on the examples you listed above, so that I can see that they produce the correct answer.