CS 261 Assignment #1

Introduction

Teams

Brendan Bell and Lucas Takiff
Bonacic Bonacic and Rohan Crossland
Asa Bonner and Jacob Endrina
Liam Bradley and Ella Slattery
Lucas Calaff and Mireia Pujol
Jinwoo Choi and Gabriel Guinn
Brett Garon and Stephen Rice
Mackenzie Leibee and Grey Roppolo
Noah McCullough and Devan Meyer
Cian Monaghan and Noah Sprenger
Spencer Racca-Gwozdzik, Noah Zimmer, and Ethan Spence

Overview

Your task for this assignment is to create several subclasses of the Player class that make moves automatically: RandomPlayer, CornerPlayer, and NextOpenPlayer. (These classes are all described in the online documentation.) The interactions below show the creation of a Board object, and invocation of several of its methods. The fillPosition method takes a zero-based column and row number, and the symbol to put in the specified position. (Note that there are no players involved in the interactions below. It's just highlighting some methods in the Board class.)

> Board b = new Board();
> System.out.println(b);
 .  .  . 
 .  .  . 
 .  .  . 
 
> b.fillPosition(1, 2, Board.O);
> System.out.println(b);
 .  O  . 
 .  .  . 
 .  .  . 
 
> b.isOpen(1,2)
 false  (boolean)
> b.boardFilled()
 false  (boolean)

The following interactions show a pair of Player instances making moves on the board instance, b, from above. The Player constructor takes a constant from the Board class describing which symbol they're playing, and a name as a string. The user inputs are in blue:

> Player x = new Player(Board.X, "Kasparov");
> Player o = new Player(Board.O, "Karpov");
> x.makeMove(b);
The current board:
 .  O  . 
 .  .  . 
 .  .  . 

Kasparov, enter col: 
2
Kasparov, enter row: 
0
> o.makeMove(b);
The current board:
 .  O  . 
 .  .  . 
 .  .  X 

Karpov, enter col: 
0
Karpov, enter row: 
1
> System.out.println(b);
 .  O  . 
 O  .  . 
 .  .  X 

The Assignment

1. Start by downloading the Board and Player classes, and starting a project in either BlueJ or Eclipse with them. You don't need to know anything about how these classes work (just which methods they support, which you can get from the documentation), and you should not modify them.
2. The Player class has a makeMove method that gets advice from the user. It displays the current game board, then asks the user to enter the column and row for the position on the board that they'd like to fill. That's no fun. Define a NextOpenPlayer class that makes moves without getting help from the outside world. Your class should extend Player and override the makeMove method with a new version that selects the first open space it comes across, starting in the upper-left corner and working left to right. If no open spaces are found on the board, return without making a move. The interactions below show a NextOpenPlayer object in action. (Well, they show it cheating — it makes three moves in a row after an initial "O" is placed on the board, but that's what we get if we call fillPosition three times in a row as player O.)

   > Board b = new Board();
   > b.fillPosition(1, 2, Board.O);
   > System.out.println(b);
    .  O  . 
    .  .  . 
    .  .  . 
    
   > NextOpenPlayer x = new NextOpenPlayer(Board.X, "Spassky");
   > x.makeMove(b);
   > System.out.println(b);
    X  O  . 
    .  .  . 
    .  .  . 
    
   > x.makeMove(b);
   > System.out.println(b);
    X  O  X 
    .  .  . 
    .  .  . 
    
   > x.makeMove(b);
   > System.out.println(b);
    X  O  X 
    X  .  . 
    .  .  . 
    
   > x.toString()
    "Spassky"   (String)
   

3. Extend Player again to create a RandomPlayer class. Objects of this type select from among the open positions on the board randomly. (You can generate random row and column values until you find a position that's open.) If the board is already full, your method should return without modifying the board. Here's a couple of random players in action, though you'll obviously get different results:

   > Board b = new Board();
   > RandomPlayer x = new RandomPlayer(Board.X, "I'm X");
   > RandomPlayer o = new RandomPlayer(Board.O, "I'm O");
   > x.makeMove(b);
   > o.makeMove(b);
   > System.out.println(b);
    .  .  O 
    .  X  . 
    .  .  . 
    
   > x.makeMove(b);
   > o.makeMove(b);
   > System.out.println(b);
    .  .  O 
    X  X  . 
    .  O  . 
    
   > x.makeMove(b);
   > o.makeMove(b);
   > System.out.println(b);
    .  O  O 
    X  X  X 
    .  O  .  
    
   > b.getWinner() == Board.X
    true   (boolean)
   

4. Next, write a third and final player class called CornerPlayer that extends RandomPlayer. (No, that's not a typo — it extends RandomPlayer and not Player.) Objects of type CornerPlayer look first to see if any of the corners are open, and fill a corner if they find one. The order in which the corners are inspected isn't important. If none of the corners are available, it should select its move randomly from among the open positions. For full credit, your new makeMove method should not generate any random numbers. Instead, it should invoke makeMove from the superclass (RandomPlayer) if no corners are open.

   > Board b = new Board();
   > CornerPlayer x = new CornerPlayer(Board.X, "Corner X");
   > CornerPlayer o = new CornerPlayer(Board.O, "Corner O");
   > x.makeMove(b);
   > o.makeMove(b);
   > System.out.println(b);
    X  .  . 
    .  .  . 
    O  .  . 
    
   > x.makeMove(b);
   > o.makeMove(b);
   > System.out.println(b);
    X  .  X 
    .  .  . 
    O  .  O 
    
   > x.makeMove(b);
   > o.makeMove(b);
   > System.out.println(b);
    X  O  X 
    .  .  X 
    O  .  O 
   

   You can pit competing strategies against each other by creating instances of two different player classes and having them alternate turns on a board. (It would look like the interactions above, but with a CornerPlayer and a RandomPlayer, for example.) It's a bit of a pain to organize this all manually, but we'll write something for the next assignment that automates the process.

5. Finally, create a new Tournament class. In it, define a playGame method that takes two player instances and plays a single round of Tic-Tac-Toe between them. You should treat the first argument to playGame as the player using X and the second as O. (You'll want to use the setSymbol method to ensure that the players are using the proper symbols too.) Your method should print the output from the winner's celebrate method and the loser's mourn method, then return the winning player (or null if the game ends in a draw).

Style Guide

• No unused variables or commented-out code is left in the class
• All instance variables are used in more than one method (if not, make them local)
• Javadoc comment at the top of each class
• All methods have Javadoc comments
• Specific values have been replaced with constants (i.e. no "magic numbers")
• Proper capitalization of variables, methods, and classes
• Use of white space to separate different sections of your code
• Consistent and appropriate indentation

Grading

• [20] RandomPlayer class organized and implemented properly
• [20] CornerPlayer class organized and implemented properly
• [20] NextPlayer class organized and implemented properly
• [25] Tournament class organized and implemented properly
• [15] Style and commenting

Extending the Assignment

Submitting