CPSC 120 Assignment #2

CPSC 120 Assignment #2
Due, Friday October 14, 2004 by 5:00 p.m.

In Lab 3, you created an applet to play a game of darts. Clearly that implementation was very simplistic - it provided a visual representation, but didn't even keep score. For this assignment, you are going to rework the darts applet to work with classes and conditional statements to provide a more robust (and fun!) game.

There are two major types of objects that we want to use for this game: Darts and DartBoards.

The Dart Class: Just like the lab, we will represent the dart with an "X" on the screen. Hence the Dart class should have the following:

Instance data that specifies the location of the dart (x,y), and the color.
A constructor that initializes the color - the color should be passed to the constructor as a parameter.
A method "Toss" that randomly assigns a location for the dart. This method should take two parameters that specify the upper limits of the dart's location. The method should make sure that the random location generated is no larger than the limits passed in.
If you choose to generate your random x and y using a generator object from the Random class, you need to declare the object to be a class (static) variable and instantiate it as follows:
```
      private static Random generator = new Random();
```
This should be placed with your declarations of instance variables. (NOTE: You could also use the random method from the Math class. It behaves in the same way as nextDouble from the Random class.)
Two accessor methods, one for each component of the location (x,y)
A method that draws the dart on the screen. Note: location should specify the center of the X (which is probably different from what you did in lab 3).

The DartBoard Class: For this program, a dartboard consists of 4 concentric circles, with a bullseye (inner-most circle) that has a radius of at least 40. The DartBoard class should have:

Instance data that specifies the size of the board (the diameter of the largest ring) and the interval (difference in size of rings).
A constant representing the minimum radius of the inner circle (in this case the 40).
A constructor that initializes the instance data. Additionally, the constructor should verify that the interval is not too big. (The interval is too big if the smallest circle has a radius smaller than 40.) If the interval specified is too big, the constructor should set the interval to the largest interval. For example, if the size of the board is 300 and the interval is 70 then the inner circle will be size 90 (radius 45) which is ok. On the other hand, if the size of the board is 300 and the interval is 80 then the inner circle will be size 60 (radius 30) which is too small. Hence in that case, the interval should be set to 73 (figure out how this is calculated in general).
A method to draw the board. Your board should have have 4 concentric circles that are different colors.
A method that takes a location (x, y) and returns a score. The scoring works as follows. Innermost ring = 50 points, 2nd ring = 25 points, 3rd ring = 10 points, 4th ring = 5 points, off the board = 0 points.

Click here for a note on positioning of the dart board.

Your applet should draw a dartboard, throw 3 darts, and report the cumulative score.

Some Hints: Do your work in small chunks testing each before going to the next. A suggested order is as follows.

First write the Dart class and an applet that draws the 3 random darts.
Next write a basic DartBoard class that has a simple constructor (with no testing for correct size) and draws the board. Add statements in your applet to test the class (try several different values for size and interval).
Next add the conditional statements to the DartBoard constructor to test for correct size. Be sure to test this by modifying the applet to try to construct dart boards that violate the size criteria.
Finally add the method to the DartBoard class that calculates the score for a given position. Note that which ring the dart is in is determined by its distance to the to the origin. So you need to compute the distance of the dart from the center of the dart board (you had the distance formula in an earlier lab). Your statement to assign points (determine which ring the dart is in) should be a cascading if.
Add calls to this method in your applet to compute the number of points for each dart. Your applet will also need to add the points up and draw the result on the applet window, appropriately labeled.

Additional requirements:

Use good programming style -- meaningful variable names, named constants, use of white space, proper indentation (note the proper style for indenting if statements). See the requirements for the last assignment.
Document your program. Have header documentation at the top of each file that gives your name, the date, the file name, and a description of the purpose of the program or the class. Have header documentation at the beginning of each method describing what the method does, including what it takes as parameters and what it returns. Have internal documentation that delineates and succinctly (and clearly) indicates what each major part of the code is doing.

Grading: Your program will be graded both on style and correctness. Style includes adherence to rules for naming of identifiers and use of white space; it also includes coding style such as the absence of unnecessary code (extra comparisons in if's or extra assignments); it includes appropriate documentation. Style will be 20% of the grade on the assignment. Correctness includes meeting all the specifications of the assignment. A program that does not compile has an automatic deduction of 70%; one that does not run has an automatic deduction of 40% no matter how "close" it is to compiling or running. Come see me if you have problems with the assignment. It is important that you get in the habit of producing correct programs!

Academic Integrity Reminder!!! Programming assignments are to be your own work. You may get help on the specifics of the assignment from no one except the instructor. You may not show your program to anyone or look at anyone else's program or share ideas with anyone about how to write the program.

Hand IN: A printed copy of your program files (the 3 Java files - you do not need to hand in the HTML file). Tar the .class, .html, and .java files and email the .tgz file to your instructor with a subject of cpsc120 project2.

CPSC 120 Assignment #2 Due, Friday October 14, 2004 by 5:00 p.m.

CPSC 120 Assignment #2
Due, Friday October 14, 2004 by 5:00 p.m.