Objectives:

• Write a simple class and test it.
• Use a class that you have written in a larger program.
• Increase your skill in using Java WorkShop.

Check-off procedure:

You must attend the recitation and sign in. You are considered to be checked off if you make a reasonable effort to complete the lab. You should try to do most of this lab prior to lab time, so that you can ask questions of the TA.

Laboratory details:

This lab involves the programming of a variation of the frog problem. In Exercise I, you will implement and test a dice class that will be used in the other two parts of this laboratory and in other laboratories later. In Exercise II you will implement the Frog class using a specification similar to that used in lecture. In Exercise III you will generalize the Frog class.

• Exercise I: The Dice Class

  Write a Dice class that encapsulates an n-sided die (n is an integer greater than 0). The constructor is:

         public Dice (int nsides) {
                 ...
         }
  

  The Dice class has accessor methods that return the number of sides and the current number rolled. The Dice class has a modifier method called Roll that picks a random number between 1 and the number of sides and returns this value.

  Create a standalone project containing the Dice class and a main program that tests the Dice class. Be sure to try calls to all of the methods.

• Exercise II: The Hopping Frog

  In this exercise, you will implement the Frog class as described and implemented during the lecture:

  A frog lives on a lily pad in LiliWorld, a straight line of lily pads stretching in two directions. The frog's home position (lily pad) is represented by 0. The frog moves in LiliWorld by tossing a coin. Heads indicates a step to the right (add one to current position) and tails indicates a step to the left (subtract one from current position). This (most intelligent) frog keeps track of how many steps it has taken and its current position. The Frog class also keeps track of the farthest points from home it reaches (in both the positive and negative directions), and the number of times it visits its home lily pad.

  Create a new standalone project to develop and test the hopping frog. The project will have a main test program, a Frog class definition (in the file Frog.java). Add the Dice class from Exercise I (using Add File under the Project menu). You do not need to copy the source file. Note: a coin is a two-sided dice. Use your Dice class for the coin.

• Exercise III: The Gambling Frog

  This exercise involves modifications to the Frog class developed in Exercise II. Create a new standalone project to implement the gambling frog. Copy the Frog.java from Exercise II into the project directory and add the copied Frog class to the project. You should also add the Dice class from Exercise I into this project, but there is no need to copy the Dice.java file since you aren't going to change it.

  Like the hopping frog, the gambling frog lives in LiliWorld. The gambling frog has both a coin and an n-sided die. This frog flips its coin to determine the direction of movement (heads for positive). It then rolls its die to see how many positions to move in the selected direction. Implement the gambling frog class by modifying your hopping frog from Exercise II. Test the program for various values of n.

  Note: the gambling frog reduces to the hopping frog when it uses a 1-sided die to determine the number of positions to move.