CS 10, Fall 2008
Assignment 3

Due: Wednesday, November 5, 9:00pm
Worth: 100 homework points

1. Complete ColorGrid.java as specified in this ColorGrid interface.
   • You may begin with this ColorGrid.java skeleton. Notice the javadocs are done for you!
   • Your job is to implement the three constructors and the ten public methods defined in the interface. Read that interface to know exactly how all of these features should work.
   • Use a copy of this application, SampleGridTester.java (with a copy of CS10Display.class in your default directory). Your results must match this part 1 display from our solution, and the following line should not print to standard output:
     
     grid() method returns original array, not a copy
2. Complete the Java application named GridMaker.java as specified below to allow a user to create new grids of various sizes, affect the colors of individual cells or areas of the grid, and display the grid on request.
   • Ultimately your program should allow interaction with the user to match these sample part 2 runs from our solution.
   • You may begin with this GridMaker.java skeleton - it solves a significant part of the problem for you. Completed are the main method and six helper methods we found useful in our solution. The main method already handles the DISPLAY and QUIT cases, and it calls seven (now incomplete) methods to handle the other cases. Your only job, if you decide to start with this skeleton, is to implement these seven methods. You may invoke the helper methods as needed - in fact, please at least use the printError methods for consistency - and you may add other helper methods if you want.
   • Notice that each of the incomplete methods in the skeleton is passed a Scanner reference as its first parameter. In main, this reference was associated with the line of text last entered by the user, and the first token was removed (it was a command, like SET). So if there is another token (s.next() is true), then it must be one of the allowable arguments for that command. See this explanation of commands and rules.
   • The second parameter in each of the skeleton's incomplete methods is a reference to the current ColorGrid object. All are void methods except newGrid. Normally that method returns a reference to a new ColorGrid, but it just returns the existing grid reference if valid data are not entered.
   • Whether you start with the skeleton or write your own complete solution, we strongly suggest you implement and test your methods one at a time instead of all at once.
   • By the way, by using input redirection you can enter commands from a file (i.e., "batch processing"). For example, all of the commands used in the "Second run" of the sample runs are in this error test file, testdata.txt. You could type the following to input these commands:
     
     java GridMaker < testdata.txt
     Then the output should match these batch results.
3. Verify that your classes compile and execute (albeit without displays) at CSIL. Then turn them both in at once from your engineering account as follows:
   
   turnin hw3@cs10 ColorGrid.java GridMaker.java
   Late projects may not be accepted.

Updated 10/22/08 (CS10Display note 10/30/08) by C. Michael Costanzo