Assessment #3 (Object Oriented Programming) – (13/8/2018)

Weighting 30%

Instructions

Time Allowed: 2 hours

Upload a .zip of your Java files (Game.java and Player.java) to moodle. You have been provided with files DiceRollerApp.java, PairOfDice.java and Die.java. No changes are allowed to these files. They must be used as they are. Make certain that the code you submit compiles. Code containing compilation errors may attract zero marks. NB Make certain you upload the correct file. This assessment is open book.

Code should be well formatted – i.e. correct indentation, placing of curly brackets...

1. Make a new package called com.ait.game.
2. Add a classes called DiceRollerApp.java, Die.java, PairOfDice.java (provided), Game.java, and Player.java to the newly created package.

└── 📁 com.ait.game
    ├── 📄 DiceRollerApp.java
    ├── 📄 Die.java
    ├── 📄 Game.java
    ├── 📄 PairOfDice.java
    └── 📄 Player.java

---

UML Diagram

+-----------------------------------+             +----------------------------------+
|         + DiceRollerApp           |             |            + Player              |
+-----------------------------------+             +----------------------------------+
|                                   |             | -name : String                   |
+-----------------------------------+             | -totalScore : int                |
|                                   |             +----------------------------------+
+-----------------------------------+             | +getName() : String              |
                  | 1                             | +getTotalScore() : int           |
                  |                               | +setTotalScore(score: int) : void|
                  | 1                             | +toString() : String             |
+-----------------------------------+             | +Player(name : String)           |
|             + Game                |             +----------------------------------+
+-----------------------------------+                              ^
| -sc : Scanner                     |                              | 2
| -numDiceRolls : int               |                              |
| -SCORE_TO_WIN : int               | 1                            | 
+-----------------------------------+------------------------------+
| +start() : void                   |
+-----------------------------------+
                  | 1
                  |
                  |
                  |                            1  +----------------------------------+            +----------------------------------+
                  +------------------------------ |          + PairOfDice            |            |             + Die                |
                                                  +----------------------------------+ 1        2 +----------------------------------+
                                                  |                                  |------------| -value : int                     |
                                                  +----------------------------------+            | -SIDES : int                     |
                                                  | +roll()                          |            +----------------------------------+
                                                  | +getValue1() : int               |            | +roll()                          |
                                                  | +getValue2() : int               |            | +getValue() : int                |
                                                  | +getSum() : int                  |            +----------------------------------+
                                                  +----------------------------------+

---

Application

The application works as follows:

1. When the application starts, it outputs a welcome slogan and asks the user to enter names for "player one" and "player two".
2. When both names have been input, it asks if you want to roll the dice.

Console Output:
Welcome to the Dice Roller application
Please enter player one name:
John
Please enter player two name:
Tom
Roll the dice? (y/n):

1. If the user enters 'n', then the "Good bye!" is output and the game ends.

Console Output:
Welcome to the Dice Roller application
Please enter player one name:
John
Please enter player two name:
Tom
Roll the dice? (y/n):
n
Good bye!

1. If the user enters 'y', then a pair of dice are rolled for each player. The program outputs the scores for each player as shown. The player to reach 20 (SCORE_TO_WIN) first is the winner. If no player reaches 20, the user is given the option of rolling the dice again.
2. If the user selects 'n' at this point, then "Good bye!" is output and the game ends.

Console Output:
Die 2 is 3
Rolling dice for player two
Die 1 is 1
Die 2 is 3
Current score for John is 7
Current score for Tom is 4
No winner yet
Roll the dice again? (y/n):
n
Good bye!

1. If there is no winner after the first round and the user enters 'y' to roll the dice again, the dice is rolled again and the scores output as shown.

Console Output:
Round 1:
Rolling dice for player one
Die 1 is 5
Die 2 is 4
Rolling dice for player two
Die 1 is 6
Die 2 is 2
Current score for John is 9
Current score for Tom is 8
No winner yet
Roll the dice again? (y/n):
y
Round 2:
Rolling dice for player one
Die 1 is 2
Die 2 is 4
Rolling dice for player two
Die 1 is 6
Die 2 is 1
Current score for John is 15
Current score for Tom is 15
No winner yet
Roll the dice again? (y/n):

1. The game continues until one or both players reaches SCORE_TO_WIN (set to 20). The first player to reach 20 is the winner. If both players reach 20 or more in the same round, then the result is a "DRAW". The game ends when a result is reached.

Console Output:
Round 3:
Rolling dice for player one
Die 1 is 4
Die 2 is 3
Rolling dice for player two
Die 1 is 2
Die 2 is 3
Current score for John is 22
Current score for Tom is 20
DRAW
Good bye!

1. Another sample is show here.

Console Output:
Welcome to the Dice Roller application
Please enter player one name:
John
Please enter player two name:
Tom
Roll the dice? (y/n):
y
Round 1:
Rolling dice for player one
Die 1 is 6
Die 2 is 1
Rolling dice for player two
Die 1 is 1
Die 2 is 3
Current score for John is 7
Current score for Tom is 4
No winner yet
Roll the dice again? (y/n):
y
Round 2:
Rolling dice for player one
Die 1 is 3
Die 2 is 3
Rolling dice for player two
Die 1 is 6
Die 2 is 6
Current score for John is 13
Current score for Tom is 16
No winner yet
Roll the dice again? (y/n):
y
Round 3:
Rolling dice for player one
Die 1 is 2
Die 2 is 3
Rolling dice for player two
Die 1 is 2
Die 2 is 4
Current score for John is 18
Current score for Tom is 22
Tom wins
Good bye!

---

Coding

DiceRollerApp.java is a class with a main method that creates an instance of the Game class and calls the start() method in the game class.

package com.ait.game;

public class DiceRollerApp 
{
    public static void main(String args[])
    {
        Game game=new Game();
        game.start();
    }
}

You are also given the classes Die.java and PairOfDice.java to represent a single die and a pair of dice respectively.

Code the start() method of Game.java to,

• Output the welcome slogan
• Use Scanner to input the names for two players as shown.
• Create 2 Player objects, and save their references in variables called player1 and player2. Player.java has a constructor that takes in the player's name as an argument.

+-----------------------------------+
|              Player               |
+-----------------------------------+
| -name : String                    |
| -totalScore : int                 |
+-----------------------------------+
| +getName() : String               |
| +getTotalScore() : int            |
| +setTotalScore(score: int) : void |
| +toString() : String              |
| +Player(name : String)            |
+-----------------------------------+

• Create a PairOfDice object and store in a variable call dice.
• Ask the user to enter y or n to roll the dice.
• If the user enters 'n', output the slogan "Good bye!" and the programme ends.
• If the user enters 'y', the roll method is called on the PairOfDice object. The values are retrieved using .getValue1 and getValue2 methods and getSum is used to get the overall score.
• Update the score for each player using setTotalScore method. In Player.java, the setTotalScore method adds the score received to the existing totalScore. It stores the accumulated score.

public void setTotalScore(int score) {
    totalScore += score;
}

• The total score for each player can be fetched using getTotalScore.
• Use an overridden toString method in the Player class to print the data below for each player.

Console Output:
Current score for John is 18
Current score for Tom is 22

• In Game.java, after the dice roll, check and output the result, draw, player one wins, player two wins or no winner yet. If there was no winner, ask the user to enter y or n to roll the dice again or not.

---

DiceRollerApp.java
Die.java
Game.java
PairOfDice.java
Player.java