CSCI1120 Introduction to Computing

CSCI1120 Introduction to Computing Using C++, Fall 2024/25

Assignment 6: Mathable Using OOP

Due: 23:59, Sat 7 Dec 2024 Full marks: 100

Introduction

The objective of this assignment is to practice the use of inheritance and polymorphism. Usage of strings, vectors and pointers is also included. You will implement the Mathable board game again but using an OOP approach this time.

In Assignment 4, we used static arrays and separate functions to implement the board game with two variant settings, namely classical Mathable and Mathable Junior, which differ in board size, rack size and number of tokens. In this assignment, you are to reimplement the board game in an OOP style by developing several classes that model the game components.

For simplicity,

• Only the Junior variant of the game is required. Its configuration is recapped in Table 1 below.

• You may assume the board size, rack size, and total number of tokens are fixed (in Mathable.h).

• No need to implement the “swap tokens” functionality – i.e., the option 'S' for the player’s action does not exist this time.

Table 1: Game configuration parameters of Mathable Junior

However, there are some new features to support:

• The number of players can be varied between 2 and 4 at the program start.

• Besides human players, we also implement computer players that make moves automatically.

• The new game has to support two special types of squares in the original Mathable. Recall that

o Restriction squares are those blue squares (in Figure 1 GUI) marked with an addition, subtraction, multiplication or division sign. To occupy a square of this kind, the player must make an equation that corresponds to the sign of that square.

One of the original game rules reads 代寫 CSCI1120 Introduction to Computing “If a player places a token on a restriction square, he may, at that moment, take an extra token (from the bag) if he so wishes. This may not be postponed to a later turn.” To make it simple, we won’t implement this rule.

o Bonus squares are those marked with “2x” or “3x” . A purple square marked 2x doubles the amount of point of the token on that square; an orange square marked 3x triples the number of points.

Game Board Representation

The gameboard is represented by a text-based grid as shown in Figure 1 below.

Figure 1: A GUI screenshot of the Mathable app versus our text-based game board representation

Program Specification

This section describes the starter code, class hierarchy, player actions, game-over conditions, the TODO classes that require your major work, and the program flow.

Starter Code

• To help you get started, you are provided with all the required source files. There is a total of 17 files implementing this program – 8 classes (header and source files) plus the main client source.

• Your task is to fill in your code for the missing parts marked with TODO comments in only 8 of these files. The last column of the Table 2 and 3 indicates whether the file has some TODO task(s) for you. Search the word “TODO:” to locate where you should fill in the missing code. Read the instructions in the TODO comment to know what is expected to do. You may remove the TODO comments after finishing the missing code.

Table 2: Header files for class definitions

	File	Description		TODO
1	Square.h	Square interface	A base class modeling a square on board	N
2	BonusSquare.h	BonusSquare interface	A subclass modeling a bonus square	Y
3	RestrictionSquare.h	RestrictionSquare interface	A subclass modeling a restriction square	N
4	Player.h	Player interface	An abstract base class modeling a player	N
5	Bot.h	Bot interface	A subclass modeling a computer player	N
6	Man.h	Man interface	A subclass modeling a human player	N
7	Mathable.h	Mathable interface	A class modeling game board and bag	N
8	RandomNumberGenerator.h	RandomNumberGenerator interface	A custom random number generator	N

Note: The constants P = 4, N = 10, R = 5, and T = 60 are defined in Mathable.h, which correspond to maximum # players, board size, rack size, bag size (total # tokens) respectively.

Table 3: Source files for class implementations and client code

	File	Description	Relation with other classes	TODO
9	Square.cpp	Square implementation	Base class	N
10	BonusSquare.cpp	BonusSquare implementation	Subclass of Square	Y
11	RestrictionSquare.cpp	RestrictionSquare implementation	Subclass of Square	Y
12	Player.cpp	Player implementation	Abstract base class	Y
13	Bot.cpp	Bot implementation	Subclass of Player	Y
14	Man.cpp	Man implementation	Subclass of Player	Y
15	Mathable.cpp	Mathable implementation	Player subclasses access board or bag via this object	Y
16	RandomNumberGenerator.cpp	RandomNumberGenerator implementation	Mathable’s setupBag() uses it for shuffling tokens	N
17	math-game.cpp	Mathable game client program	The main() function here	Y

• We suggest the following development order.

o The subclasses of Square: RestrictionSquare and BonusSquare;

o Next is the Mathable class;

o Then finish the base classes first: Player;

o Followed by subclasses of Player: Bot and Man;

o Finally, the game client program: math-game.cpp.

Class Hierarchy

Figure 2: The class inheritance hierarchies and relationship between classes

The Mathable class has a 2-D array of Square pointers, namely board[N][N], which implements the game board. BonusSquare and RestrictionSquare are subclasses of Square. They override the virtual function toString() to return more specific information like “3x” or “+” . The Player class keeps a pointer, namely mGame, which points to a Mathable object. Then methods in the Player class or its subclasses can make moves, i.e., placing tokens on the game board, by calling the methods provided by Mathable. Note that the Player class is abstract since it has a pure virtual method called makeMove(). You cannot create objects of this class. Man and Bot are concrete subclasses of the Player class modeling a human player and a computer player respectively. They reuse the parent-level data such as score and rack as well as methods such as getScore() and rackSize(). They override their parent’s virtual makeMove() method to exhibit different behaviors in making moves – a human player enters a move via the keyboard whereas a computer player picks the move that obtains the highest points from all possible moves.

Besides the classes, we also define a type alias of int called Token in Square.hand we tend to use this alias for the type of variables storing a token. For example, a player’s rack is implemented as a vector storing the tokens, instead of writing vector rack, we would write vector rack, which looks more readable.

Human Player Actions:

There are 3 options of game actions that a human player (Man) can choose in each turn:

1. Play (P): play a move, i.e., select a token on the rack to place at a specified cell on the board.

2. End (E): end the current turn (if the player can’t see any more moves to make).

3. Terminate (T): terminate the game (prematurely). Then players’ current total scores are compared to see who wins the game.

You may refer to Assignment 4 specification for their description.

Computer Player Actions:

A computer player (Bot) has no options for actions. It keeps playing all playable moves in a greedy manner, i.e., pick a combination of a token on its rack and a square on the board that can maximize the points gained by the current move, until there are no more possible moves. Then it passes the turn to the next player.

Game-over Conditions:

In this assignment, there are three game-over conditions:

(1) There are no tokens left in the bag and one player has used up all tokens on his rack.

(2) Every player has passed their turn to the next since they have no more possible moves.

• Note: This situation can happen even if the bag is not empty (since the swap-tokens function is not supported in this assignment).

• Hint: The possibleMoves() method provided by the Mathable class, to be discussed, can facilitate the detection of this situation.

(3) A human player enters option T to terminate the game. (This allows us to end a game earlier as we wish, making program testing more flexible.)

Like Assignment 4, a draw game can happen if more than one players attain the same highest score.