Project 1 - Battleship Game

Transcription

1 Project 1 - Battleship Game Minimal Submission Due: Friday, December 22 th, 2006 Revision History Final Project Due: Sunday, January 21 th, 2007 Dec 7th, 2006, v1.0: Initial revision for faculty review. Dec 11th, 2006, v1.6: Final revision released to students. Jan 8th, 2006, v1.7: The output format for the board was changed to match the try submission. To clarify, there should be no space at the end of each row. Overview In this project, you will be required to write a simple one sided battleship game. Your program will start by specifying a board size, and then reading an input file with ships placements. From there you will have a chance to fire missiles to try to sink the ships. You will also be able to view the board, view the ship placement (cheat mode) and get the game statistics. Objectives Gain further experience using two dimensional arrays Practice using Scanner with System.in Obtain additional experience writing programs in Java Gain more experience designing classes Getting Help You may get help from your instructor(s) and the teaching assistants. Anything else is not allowed and is subject to the penalties listed in the DCS Policy on Academic Dishonesty. This includes but is not limited to: Obtaining detailed help from any other people Providing detailed help to other people Sharing source code with anyone, by any means or medium. We certainly do not expect there to be absolutely no communication between the students of this class; we know that people tend to learn very well that way. However, we expect that you will limit your discussion of this project to determining the specification of the problem. If you have any doubt if what you would like to do might violate our rules, please see your lecture instructor for clarification. Don't forget that the CS tutoring center is available to you. Program Requirements

2 Battleship is a popular game played on a board representing a rectangular portion of the sea. It is broken up into a grid of square cells, each one having a unique pair of coordinates. Battleships are placed on the board in a straight horizontal or vertical line. The opponent does not know where the battleships are; he or she fires missiles into the sea, specifying coordinates, and is only told if it was a hit or a miss. The player who fired the missile uses this information to guess the locations of the battleships. A battleship is sunk when all of its sections have been hit by a missile. The goal is to sink all the battleships. Usually it is a two-player game, each one having his/her own board. You will create a one-player game, where the program places battleships on a board and the user is the opponent trying to sink them. Your program must be able to create a new board, place the ships as specified in a file, be able to fire missiles at the user-specified the locations, and keep track of the game's state. The ships cannot be placed off the board or on top of each other. Game statistics must be kept throughout the game, including keeping track of the number of hits and misses, the total number of missiles fired, and the number of ships sunk. Command Line The game shall be started as follows: java Battleship N filename The value N represents the dimensions of the board. Since a board is always square, there are N columns and N rows. (For a board of size N, the legal row and column coordinates are 0 to N-1.) Because single letters will be used to label the rows and columns of the board, the maximum size allowed will be 26. For example, with N=10, the range of letters will be A-J. Input Format The filename is the name of a file whose first line contains the number of ships, followed by one line each for each ship position, in the following format: startrow startcolumn endrow endcolumn startrow and startcol are each single letters which specify the starting position of the ship. endrow and endcol are each single letters which specify the ending position of the ship. For this project, you are guaranteed that the orientation of the ships will be either horizontal or vertical (no diagonals). You will also be guaranteed that the file will contain no more than 26 ships, for output purposes. An example input file can be found here. Example If a board size of 10 has been specified and the input file contains the following:

3 2 C C C E D E H E then the initial board setup would be as follows: A C - - A A A D B E B F B G B H B (More on output format later.) If any errors occur in the data used by the game upon startup, an error message must be printed on standard error and the program halted. Here is a table of possible error situations and the messages displayed as a consequence. error Illegal number of arguments* message to be displayed (all terminate with a new line) Usage: java Battleship N config-file 1 st command line argument is not an integer* Usage: java Battleship N config-file 1 st command line argument < 5* Board must be at least 5 by 5. 1 st command line argument > 26* Board must be at most 26 by 26. File named by second argument cannot be opened. Specifications of ships cause them to overlap. Specifications of ships extend beyond the boundaries of the board. Cannot open file filename. Fig. 1: Error Situations and Messages *required for minimum submission Overlapping or out-of-bounds ships in file filename. Overlapping or out-of-bounds ships in file filename. The first thing that happens after the program is started is that the board layout is displayed as if the user had typed "board". The user will then be prompted for a command by displaying "> " on a new line. The commands are as follows: Command Description Print out the placement of the water and missiles on the board. Water must be marked with a hyphen: -

4 Each previous fired missile destination must be marked with either an X or an O signifying a hit or a miss, respectively. board This printout must not show the placement of the ships. For the precise format of the output, see the Output Format section later in this document. Note that you must allow for a single letter for the row and column, separated by a single space. Print out the placement of the ships on the board. Water must be marked with a hyphen: - ships Each ship must be represented by a letter corresponding to its position in the input file. For example, the first ship should be marked as A, the second ship as B, and so on. This printout must not show the placement of the missiles. For the precise format of the output, see the Output Format section later in this document. Note that you must allow for a single letter for the row and column, separated by a single space. Fire a missile at the square at the given row and column. Both coordinates will be given as single letters separated by a single space. The status of the missile must be changed depending on if it is a hit or a miss at the current spot on the board. If there is a missile already there, the user will get the error message "Coordinates previously fired upon." on standard output. If the coordinates are out of range, the user will get the error message "Illegal coordinates." on standard output. fire row col If the missile hits a part of the sea, the user will get the message "Miss!" on standard output. If the missile hits a part of a ship, the user will get the message "Hit!" on standard output. If the missile hits a part of a ship, causing it to sink, the user will get the message "Sunk!" on standard output. If the wrong number of arguments is provided, or the row and columns specified are not letters in the valid range, the user will get the error message "Illegal coordinates." Afterwards the program will behave as if "board" had been entered by the user. If, after a "fire" command, all the battleships are sunk, the game will display, on a separate line: You win!

5 After a win has been determined, the program will behave as if the commands "stats" and "quit" have been entered. stats help quit garbage Print the number of missiles fired, the number of hits, the number of misses, the hit ratio percentage, and the number of ships sunk. When computing the percentage for the hit ratio, perform the operation as: percentage = * numberofhits / totalmissilesfired Displays the following usage message: Possible commands: board - displays the user's board ships - displays the placement of the ships fire r c - fires a missile at the cell at [r,c] stats - prints out the game statistics quit - exits the game Exit the program. A blank command, or a command with just whitespace, should quietly cause a reprompting. If any other command is entered, the user will get the error message "Illegal command." on standard output. Fig. 2: User Command Input Semantics Output Format When the board is printed, it will be printed as a grid. Rows are horizontal, increasing in coordinates downward, and columns are vertical, increasing in coordinates to the right. Column letters are displayed above the first row starting with "A" as the first column and incrementing thereafter. Row letters are displayed to the left of the first column, starting with "A" as the first column and incrementing thereafter. Un-fired-upon water is indicated with a hyphen. Water that has been fired upon is indicated with the letter "O". Un-fired-upon ship locations are indicated by their position in the input file, "A" for the first, "B" for second, and so on. Ship locations that have been hit by a missile are marked with an "X". All items displayed are placed in a 2-space field, left-justified. rev1.7 - For the last column, you should not print an extra space after it. An example output with correct spacing can be found here. Project Design You are required to use three technologies when designing this project: inheritance, exceptions, and file input. Uses of Inheritance 1. [Required] You shall use several different classes to represent the current contents of a cell on the board. For example, the board can be be composed of abstract Cell references, which is then populated with instances of concerete subclasses such as Water, ShipSection (OK or damaged), or MissedMissile.

6 2. [Optional] Use several different classes to represent the actions of the six user commands. Populate a container with associations between instances of these new classes and the string name of the first word in each command listed in Figure 2. When the user types something in, a command is looked up and executed. Use of Exceptions Should an error occur that cannot be handled at the point of detection in the code, an exception should be raised and caught somewhere where the program can gracefully handle it or terminate. For example, you will likely want to use exceptions to deal with file input errors. You may define your own exception classes. Use of System.exit( int ) for any purpose is forbidden in this project. Sample Run As you follow the sample run below, assume that the file input-2.2 contains the following data: 5 D H H H C B F B C D C F H D I D F C F D Any text that the user types in is shown in this way. %java Battleship 10 input-2.2 A C D E F G H > ships A C - B - C C C D - B A - - E - B A - - F - B E E A - - G A - - H D A - - I D > fire Illegal coordinates. > fire A Z Illegal coordinates.

7 > fire A A Miss! A O C D E F G H > fire F C Hit! A O C D E F - - X G H > fire F D Hit! Sunk! A O C D E F - - X X G H > ships A C - B - C C C D - B A - - E - B A - - F - B E E A - - G A - - H D A - - I D > stats Number of missiles fired: 3 Number of hits: 2 Number of misses: 1 Hit ratio: % Number of ships sunk: 1 > help Possible commands:

8 board - displays the user's board ships - displays the placement of the ships fire r c - fires a missile at the cell at [r,c] stats - prints out the game statistics quit - exits the game > abacab Illegal command. > > quit Project Submission Minimal Submission In order to meet minimum submission qualifications you must submit the following: Your Battleship class: It must contain a main program that error-checks the command line arguments. The board size must be correct, and the user must specify some input file. You do not need to verify the existence of the input file for this part. In order to verify the board size, you will have to use exceptions so that you can guarantee the argument is a number. Your abstract class or interface for the objects that will be placed on the board. Your concrete class that represents empty water in a board Code that creates the board and populates all the cells with water. Code that responds to a "board" command and displays the board with the water cells. Code that responds to a "quit" command and terminates the program. Code that reprompts correctly, and can handle blank user commands. When you have these classes working to the standard set by your professor, submit all your source code using the following command: try 232-grd project1-min Battleship.java... The ellipsis ("...") means that you may submit as many other java files as your design requires. Final Submission When you are satisfied and confident that your project meets final submission standards, submit all your source code using the following command: try 232-grd project1 Battleship.java... $Id: writeup.html,v /01/08 16:57:56 vcss232 Exp vcss232 $