Harvard University Complexity of Algorithms and Efficiency of Programs Questions

There will be a total of 7 required Java classes created for this assignment: Piece.java,

SlowPiece.java, FastPiece.java, SlowFlexible.java, FastFlexible.java, Board.java and

GameDemo.java. You are free to create extra classes if needed.

Start by defining a Piece class with the following fields:

• Name: A String (eg. ‘Jedi’, ‘Droid’, etc.)

• Colour: A String (eg. ‘Black’, ‘Red’, etc.)

• Position: A point described by a pair of integers (eg. [2, 4], [1, 1], etc.).

Assume that the game board is an 8 X 8 grid. The position is a coordinate ([x, y]) on the board, with

the values of x and y each taking a value between 0 and 7. The top left corner of the board is taken

to be the origin ([0, 0]). You can define Position in a separate class or use classes from the Java

standard library if you wish.Implement the following methods:

• Constructor: A constructor that creates a Piece object with the given name, colour and

position.

• Getters and Setters: Appropriate methods to set, change and access fields.

• toString(): A method to display the Piece Object’s fields.

Next define a SlowPiece class – A Piece that moves left or right exactly one step per move. Your

SlowPiece should extend the Piece class, implementing a constructor and redefining the inherited

toString method via overriding.

In addition, implement the following method:

• move (String direction): A method to move the piece left or right by one space. This method

will accept a direction parameter. If a move is requested that would take the Piece off the

edge of the board, simply return without doing anything.

Define a FastPiece class – A Piece that moves left or right a specified, arbitrary number of steps

per move. Your FastPiece should extend the Piece class, implementing a constructor and redefining

the inherited toString method via overriding.

In addition, implement the following method:

• move (String direction, int n): A method to move the piece left or right by a specified

number of spaces. This method will accept a direction parameter and a number of spaces.

If a move is requested that would take the Piece off the edge of the board, simply return

without doing anything.

A flexible Piece is one that can move up or down as well as right or left. Extend the class hierarchy

developed so far to include these two new kinds of Pieces. Define a SlowFlexible class that extends

the SlowPiece class and a FastFlexible class that extends the FastPiece class. Define methods in

these classes as needed.

Next define a Board class – The Board class will hold the 8 X 8 game board. Each position of the

board either contains a Piece or is empty. Since the pieces move around on the game board, any

location may contain any type of Piece. Consider what data structure you wish to use to represent

the board.

Implement methods to do the following in the Board class:

• Add a new Piece to the game board.

Note: a new Piece can be added to a location only if none exist at that location; display an error

message if the Piece cannot be added.

• Move a Piece at a given location in a given direction by a given number of spaces. Display

an error message if the Piece cannot be moved.

• Display the game board, showing the name, color and type of each Piece on the game board

at its current location. You can use a simple text-based display to show the board and the

Pieces on it. For example, your display might look like this:

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JediBlueS CloneRedF

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DroidBlueFF-

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CloneBlueSF

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TroigRedF

In the above display, there is a Jedi (blue colour, slow piece) and a Clone(red colour, fast

piece) in the first row. There is a Droid (blue colour, fast flexible piece) in the second row…

and so on.

Finally define a GameDemo class – The GameDemo class should accept commands from a user

to create Pieces and move them on an 8 X 8 game board, and display the game board.

You should use the following command syntax, with each command appearing on a new line.

Words in plain, Roman script should appear verbatim in the command. Words in Italic script take

one of several possibilities that are explained. Square brackets imply optional parameters.