CS 312 Assignment 4 - Conditional Execution

Programming Assignment 4: Individual Assignment. You must complete this assignment by yourself. You cannot work with anyone else in the class or with someone outside of the class. You may not copy solutions from the world wide web. You are encouraged to get help from the instructional staff.

Placed online: Wednesday, September 24
20 points, ~2% of total grade
Due: no later than 11 pm, Friday, October 3
General Assignment Requirements

The purposes of this assignment are:

  1. To practice creating a structured program to solve a problem.
  2. To write methods that use parameters.
  3. To write an interactive program.
  4. To practice writing programs that use conditional execution.

For this assignment you are limited to the language features in chapters 1 through 4 of the textbook and the logical operators from section 5.3. (&& -logical AND, || - logical OR, and ! -  logical NOT)


TIP: Start early. Start now. This program is in some ways more difficult that the first three. You must write methods that return values, get input from the user with Scanner, and use conditional logic (if - else).

Description: Write a program to allow a human to play a game of Rock, Paper, Scissors versus the computer. The sample programs (rps1.txt, rps2.txt, and rps3.txt) show 3 runs from my solution to this problem using the default random player.

Give the same human name and computer choices, your program must match this output exactly. Use a diff tool such as the one at this website ( www.quickdiff.com) to ensure your program produces the correct output. Even minor differences in characters will cause you to fail grading tests and lose points.

The program:

This is not an easy program, mostly due to the size of the program. The individual steps are not too difficult, but their are many steps. The program description above gives you a rough idea of how to break the program up into parts.

Have a high level structure and then implement parts of that structure (the individual methods) one at a time, testing to make sure they work before going on. You may have to write some testing code that will not be part of the final program. Do not write the whole program in main and then try and break it up into methods.

Here are some tips on the various parts of the program.

1. main method.

The main method creates the an object of type RandomPlayer. If no values are sent to main a default RandomPlayer is created. If you send an argument to the main method it is assumed it is a single value that can be parsed to an int. (These pages describe how to send an argument to the main method in BlueJ or Eclipse). Pass the RandomPlayer object to the methods that need it. Feel free to share examples of your output for non default players on Piazza.

In the main program declare a Scanner variable that is hooked up to System.in. You need to include the line of code

import java.util.Scanner;

at the top of your program.

Pass the Scanner object you create as a parameter to any methods that need it. The main method should not have a lot of statements, instead it shall call other methods.

2. ask the user for their name. This is a good candidate for a separate method that returns a String.

3. ask the user how many rounds of Rock, Paper, Scissors they want to play. This is another good candidate for a separate method that returns an int. You do not have to do any error checking on the user input. If they enter something that is not an int it is appropriate for the program to end due to a runtime error.

Recall that if you use the nextInt() method from the Scanner class you will have to call the nextLine() method after that to advance the Scanner past the end of line character. The nextInt() method does not advance past the end of line character.

4. playing the rounds of the game Given our current programming tools this will be the largest and most complex method. It is in turn broken down into several parts. You will need a number of local variables in this method.

5. ask the user what their choice is. The user will enter an integer as their choice. You do not need to error check their input. Recall that if you use the nextInt() method from the Scanner class you will have to call the nextLine() method after that to advance the Scanner past the end of line character. The nextInt() method does not advance past the end of line character.

6. have the computer make a random choice. To do this call the getComputerChoice method on the RandomPlayer object created in main and passed as a parameter.

You must use the provided RandomPlayer.java file. Do not change it..  Do not use Random() (from java.util) directly and do not use Math.random().  Keep RandomPlayer.java in a separate fil. Do not turn in RandomPlayer.java.

7. print out each player's choice. You will find it useful to have a method that is passed an  int parameters and returns the correct String for that int. In this program 1 represents "Rock", 2 represents "Paper", and 3 represents "Scissors".

8. print the results of that round. This is the most algorithmically difficult part of the assignment because there are nine possible outcomes and using the programming tools of chapters 1 - 4 and section 5.3 it is difficult to remove redundancy.

The nine possible outcomes are

Computer Choice Human Choice Result
Rock Rock Draw
Rock Paper Human Wins
Rock Scissors Computer Wins
Paper Rock Computer Wins
Paper Paper Draw
Paper Scissors Human Wins
Scissors Rock Human Wins
Scissors Paper Computer Wins
Scissors Scissors Draw

You must follow the format as shown in the sample output.

9. after playing the specified number of rounds display how time the user won, how many times the computer won, and how many draws occurred.   The method that runs the rounds shall call a method to display this information.

10. declare who the better player was based on the number of wins.  This can be part of the results method but will require some conditional execution with if statements. \

Additional tips. You may find it useful to have class constants for the integers representing rock, paper, and scissors. Recall class constants are declared at the top of the class outside any methods:

public static final int ROCK = 1;

Style issues. We will grade style as well as correctness. Did you provide a good structure to the program using static methods? Did you use meaningful identifiers? Did you provide consistent tabbing and spacing for code inside loops and if statements? Did you provide comments for you methods and your code.

When finished turn in your RockPaperScissors.java file via Canvas.

Provided File Responsibility
RandomPlayer.java (Provided file) Provided by me. Do not turn in. Do not alter.
RockPaperScissors.java (Provided shell) You and me. (Okay, mostly you.)

Checklist: Did you remember to:


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