CS1101C Lab 4 (Odd Week)

Let's Play Chess!

The deadline for this lab question is Wednesday 30 March 2005, 23:59:59 hours.

The name of your C program file must be called chess.c, files with any other name will not be marked.

Background

Chess is a fascinating game of skill and strategy where expert players pit their intelligence and wit against each other on a square board. Each chess board is an 8 x 8 board containing 64 squares.

The Teams

The two teams are called “White” (abbreviated as “W”) and “Black” (abbreviated as “B”). A chess piece is either a White piece or a Black piece.

The Pieces

There are six different types of chess pieces. Their names and abbreviations are shown in the following table:

Piece
 Abbreviation
Pawn
P
Knight
N
Bishop
B
Rook
R
Queen
Q
King
K

A chess piece is abbreviated by its colour followed by the type of piece. Here are some examples:

The Board

The chess board consists of an 8 x 8 square board with 64 squares. The initial position of a chess board is shown below: 
BR BN BB BQ BK BB BN BR
BP BP BP BP BP BP BP BP
.. .. .. .. .. .. .. ..
.. .. .. .. .. .. .. ..
.. .. .. .. .. .. .. ..
.. .. .. .. .. .. .. ..
WP WP WP WP WP WP WP WP
WR WN WB WQ WK WB WN WR

Note that we use two periods (or full-stops) to indicate an empty square. Each square can only be occupied by one piece at a time. So, the top left hand corner is occupied by the Black Rook, and on its right is the Black Knight, and so on. The four middle rows begin as all empty squares.

Each square has coordinates in the form (r,c), where r is the row number and c is the column number. The top-left square has coordinates (0,0). The bottom right square has coordinates (7,7). So, in the initial position of a chess board shown above, the Black Queen (BQ) has coordinates (0,3).

Chess Moves

A chess move is simply specified by a source coordinate and a destination coordinate. It means that the piece at the source coordinate is to be moved to the destination coordinate. So, if the source coordinate is (6,4) and the destination coordinate is (4,4), it means that the White Pawn which is in front of the White King will move two steps forward.

Each chess move is stored in a data file as four integers; source_row, source_column, destination_row, destination_column. The above chess move will be stored as:

6 4 4 4

Suppose another chess move is:

0 1 2 3

this means that the piece at coordinate (0,1) will be moved to coordinate (2,3).

The data file contains a list of such chess moves. The number of moves in each data file is unknown.

Captures

If the source coordinate and the destination coordinate represent two pieces of different colour, the piece at the destination coordinate is captured and removed by the piece at the source coordinate. The piece at the source coordinate then moves to the destination coordinate.

Invalid Move

For simplicity, we assume that the data file contains mostly legal moves. There are only two types of erroneous moves we want to catch and disallow:

  1. “Friendly fire” errors: the piece at the source coordinate is the same colour as the piece at the destination coordinate.
  2. “No one’s there” errors: there is no piece at the source coordinate.

We are not concerned with all other errors, including pieces not moving as they do in a normal chess game, pieces jumping over pieces, players not taking turns, etc. You may also assume that all the coordinates are always between 0 to 7 inclusive.

Purpose

The purpose of your program is to simulate a chess game starting from the initial chess board position, and reading a list of moves from a data file. Your program must then show the final chess board position as well as print a list of statistics showing the number of each type of erroneous moves and the number of each piece captured.

Statistics

The statistics we want to capture are:
  1. Number of each type of piece captured (e.g. WP, WR, ...)
  2. Number of “friendly fire” erroneous moves.
  3. Number of “no one’s there” erroneous moves.

Sample Run

Assume that the text input file is always called chess1.txt. You may copy the file into your current directory by typing the following cp (copy) command at the Unix prompt. Highlight the entire line, right-click on the mouse and choose “Copy”, then switching to your Secure Shell Window, right-click on the mouse and choose “Paste”. Press Enter to execute the command.

cp ~cs1101cl/www/lab4/oddweek/chess1.txt .

The following shows one sample run. Your program must work with other chess1.txt files that contain different text. Note that $ indicates the Unix prompt. Follow the sample output exactly, else marks will be deducted.

Sample Run 1

The following shows a sample run for the sample text input file chess1.txt. 
$ gcc -Wall chess.c -o chess
$ ./chess
Final position:
BR .. BB BK .. BB .. BR
BP BP BP .. .. BP BP BP
.. .. BP .. .. .. .. ..
.. .. .. .. WP BN .. ..
.. .. .. .. .. .. .. ..
.. .. .. .. .. WN .. ..
WP WP WP .. .. WP WP WP
WR WN WB .. .. WR WK ..

Capture statistics:
WP: 1
WR: 0
WN: 0
WB: 1
WQ: 1
WK: 0

BP: 1
BR: 0
BN: 1
BB: 0
BQ: 1
BK: 0

Error statistics:
Friendly fire: 1
No one's there: 1
$

Things To Notice

  1. The first line in the text input file chess1.txt contains a “friendly fire” erroneous move.
  2. The last line in the text input file chess1.txt contains a “no one’s there” erroneous move.
  3. The two possible types of errors can occur anywhere in the file, not necessarily just the first and last lines. The above is just an example text input file.

All The Best!

Luck does not feature in programming.

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