CS 10, Fall 2008
Assignment 4

Due: Wednesday, November 19, 9:00 pm
Worth: 100 homework points

1. Complete FigurePrinter.java to provide the public interface described in the javadocs. Be sure to read the method descriptions in those javadocs too, as they are more detailed than the following notes.
   • Start with this FigurePrinter skeleton, and follow the instructions there (in upper case). Notice the javadocs are complete for all public parts. Do not change the existing method signatures, but you may add methods if you want.
   • Mind these implementation notes too.
   • Use FigureTester.java to test your class. Results should almost exactly match this generic test run (the compareTo results might vary, but the signs of these results should match).
2. Write the two subclasses, RectanglePrinter and TrianglePrinter, to have the same public interface shown in our solution's javadocs (your solution should have javadoc comments too, but they are not required). Both subclasses store data in addition to the data stored in FigurePrinter, and both classes must override print() and equals(Object other). FigureTester.java should be used to test these classes too - but first remove the six lines labelled "/*TEMP" or "TEMP*/" and run it with either r (for rectangle) or t (for triangle) as the first command line argument. See the test runs below.
   1. Write RectanglePrinter.java.
      • See part 2a of the implementation notes.
      • If you run FigureTester as follows (after deleting the TEMP comment delimiters):
        
        java FigureTester r
        results should match this rectangle test run.
   2. Write TrianglePrinter.java
      • See part 2b of the implementation notes.
      • If you run FigureTester as follows (after deleting the TEMP comments):
        
        java FigureTester t
        results should match this triangle test run.
3. Write an application called FigureDisplayer.java to display a user-specified number of random rectangle and triangle figures.
   • Process 0 to 2 command line arguments. If there is a first argument, assume it is an integer, parse it, and use it as the number of figures to print; otherwise set that number to 5. If there is a second argument, assume it is an integer, parse it, and use it as the seed for a random number generator; otherwise create the random number generator without any seed. [See java.util.Random.]
   • Create an ArrayList<FigurePrinter> to store random figures (either 5 or the number requested on the command line). For each figure, randomly select: (1) rectangle or triangle - our solution uses the nextBoolean method of Random to select a boolean value (true means rectangle); (2) a random character in the printable range of the ASCII codes (33 to 126, by proper use of the nextInt method of Random) - you can run this ListOfPrintable.java to see the complete list of these characters and codes; (3) a random offset in the range 0 to 50; (4) a random width less than or equal to 20; and if a rectangle, then (5) a random height less than or equal to 10.
   • Sort the list. If you wrote the compareTo method of FigurePrinter correctly, you can use the Collections.sort method to do so in a single statement. [See java.util.Collections.]
   • Print every figure in the list in sorted order, separated by one blank line between each pair of figures.
   • Here is a sample run where the user requested 30 figures (no seed, so the results are completely random):
     
     java FigureDisplayer 30
     

     And here are two runs, where a seed is specified:

     java FigureDisplayer 3 765 and java FigureDisplayer 3 792
     Your results can match the results of these runs if you make random selections in the order listed above, and use these same seeds. But it is not necessary to exactly match our results.
4. Be sure your classes will compile and execute correctly at CSIL. Additional copies of FigureTester.java, the FigurePrinter.java skeleton and other files are in ~mikec/cs10/hw4/. There are four files to turn in:
   
   turnin hw4@cs10 FigurePrinter.java RectanglePrinter.java TrianglePrinter.java FigureDisplayer.java
   Alternatively, you can use the following procedure if you want:

   • Create a new directory (if necessary), and copy each of the required files to it.
   • Change to that directory. Verify that it contains no other .java files. Then type:
     turnin hw4@cs10 *.java

   Late projects may not be accepted.

Updated 11/5/08 by C. Michael Costanzo