COMP90041 - Assignment 1 - Solved

1           Nim: A Game of Strategy
This project is the first in a series of three, with the ultimate objective of designing and implementing a simple variant of the game of Nim in Java. Nim is a two-player game, and the rules of the version used here are as follows:

•    The game begins with a number of objects (e.g., stones placed on a table).

•    Each player takes turns removing stones from the table.

•    On each turn, a player must remove at least one stone. In addition, there is an upper bound on the number of stones that can be removed in a single turn. For example, if this upper bound is 3, a player has the choice of removing 1, 2 or 3 stones on each turn.

•    The game ends when there are no more stones remaining. The player who removes the last stone, loses. The remaining player wins.

•    Both the initial number of stones, and the upper bound on the number that can be removed, can be varied from game to game, and must be chosen before a game commences.

1.1         Example Gameplay
Here is an example play-through of the game, using 12 initial stones, and an upper bound of 3 stones removed per turn:

•    12 stones on the table.

•    Player 1 removes 3 stones. 9 stones remain.

•    Player 2 removes 1 stone. 8 stones remain.

•    Player 1 removes 1 stone. 7 stones remain.

•    Player 2 removes 2 stones. 5 stones remain.

•    Player 1 removes 3 stones. 2 stones remain.

•    Player 2 removes 1 stone. 1 stone remains.

•    Player 1 removes 1 stone. 0 stones remain.

•    Player 2 wins.

2           Assignment: Implement Nim’s Basic Game Mechanics
For this first project, the focus will be on creating two players and playing for multiple games:

1.        Your program will begin by displaying a welcome message.

2.        The program will then prompt for a string (no space in the string) to be entered via standard input(the keyboard) - this will be the name of Player 1. You may assume that all inputs to the program will be valid.

3.        The program will then prompt for another string (no space in the string) to be entered - this will bethe name of Player 2.

4.        The program will then prompt for an integer to be entered - this will be the upper bound on thenumber of stones that can be removed in a single turn.

5.        The program will then prompt for another integer to be entered - this will be the initial number ofstones.

6.        The program will then print the number of stones, and will also display the stones, which will berepresented by asterisks ‘*’.

7.        The program will then prompt for another integer to be entered - this time, a number of stones to beremoved. Again, you may assume this input will be valid and will not exceed the number of stones remaining or the upper bound on the number of stones that can be removed.

8.        The program should then show an updated display of stones.

9.        The previous two steps should then be repeated until there are no stones remaining. When thisoccurs, the program should display ‘Game Over’, and the name of the winner.

10.    The program should then ask user whether the players wanted a play again. The user is promptedto enter ‘Y’ for yes or ‘N’ for no. If the user enters ‘Y’, that is, the user wants to play another game, repeat steps 4-10. Otherwise, the program should terminate. Note, any input apart from ’Y’ should terminate the game.

2.1         Example Execution
After executing your program, the flow should be something like this:

Welcome to Nim

Please enter Player 1’s name:

Luke

Please enter Player 2’s name: Han

Please enter upper bound of stone removal:

3

Please enter initial number of stones:

12

12 stones left: * * * * * * * * * * * *

Luke’s turn - remove how many? 3

9 stones left: * * * * * * * * *

Han’s turn - remove how many? 1

8 stones left: * * * * * * * *

Luke’s turn - remove how many? 1

7 stones left: * * * * * * *

Han’s turn - remove how many? 2

5 stones left: * * * * *

Luke’s turn - remove how many? 3

2 stones left: * *

Han’s turn - remove how many? 1

1 stones left: *

Luke’s turn - remove how many? 1

Game Over Han wins!

Do you want to play again (Y/N):

Y

Please enter upper bound of stone removal: 5

Please enter initial number of stones: 15

15 stones left: * * * * * * * * * * * * * * *

Luke’s turn - remove how many? 1

14 stones left: * * * * * * * * * * * * * *

Han’s turn - remove how many?

2

12 stones left: * * * * * * * * * * * *

Luke’s turn - remove how many? 3

9 stones left: * * * * * * * * *

Han’s turn - remove how many? 4

5 stones left: * * * * *

Luke’s turn - remove how many? 5

Game Over Han wins!

Do you want to play again (Y/N):

N

2.2         Some Hints
Please note that:

•    You need to create a class called Nimsys with a main() method to manage the above game playing process.

•    When a player’s name is entered, a new object of the NimPlayer class should be created. You need to create the class NimPlayer. Player 1 and Player 2 are two instances of this class. This class should have a String typed instance variable representing the player name. This class should also have a removeStone() method that returns the number of stones the player wants to remove in his/her turn. You will lose marks if you fail to create two instances of NimPlayer.

•    Add other variables and methods where appropriate such that the concept of information hiding and encapsulation is reflected by the code written.

•    There is NO blank line before the first line, i.e., no println() before ‘Welcome to Nim’.

•    There is a withespace between stones left : sentence and * * *, and also between all * * *, but NO withespace at the end of * * *.

•    The line that prints the winners name should be a full line, i.e., ‘Han wins!’ is printed out using println().

•    And there are NO blanks after the last stone in lines displaying asterisks.

•    Keep a good coding style.

You do not need to worry about changing your output for singular/plural entities, i.e., you should output ‘1 stones’, etc.

3           Important Notes
Computer automatic test will be conducted on your program by automatically compiling, running, and comparing your outputs for several test cases with generated expected outputs. The automatic test will deem your output wrong if your output does not match the expected output, even if the difference is just having an extra space or missing a colon. Therefore it is crucial that your output follows exactly the same format shown in the examples above.

The syntax import is available for you to use standard java packages. However, please DO NOT use the package syntax to customize your source files. The automatic test system cannot deal with customized packages. If you are using Netbeans as the IDE, please be aware that the project name may automatically be used as the package name. Please remove the line like package ProjA; at the beginning of the source files before you submit them to the system.




1.    Upload to the server your Java code files named “Nimsys.java” and “NimPlayer.java”, and the test input data files “test0.txt”.

2.    Run command: javac *.java (this command will compile all your java file in the current folder)

3.    Run command: java Nimsys < test0.txt > output.txt (this command will run the Nimsys using contents in ‘test0.txt” as input and write the output in output.txt)

4.    Run command: more output.txt (this command will show the your program’s output)

5.    Compare your result with the provided output file test0-output.txt. Fix your code if they are different.

6.    When you are satisfied with your project, submit and verify your project using the instructions givenin the Section 6.