How do I model a chessboard when programming a computer to play chess?

Question

What data structures would you use to represent a chessboard for a computer chess program?

Answer 1

An array would probably be fine. If you wanted more convenient means of "traversing" the board, you could easily build methods to abstract away the details of the data structure implementation.

Answer 2

When creating my chess engine I originally went with the [8][8] approach, however recently I changed my code to represent the chess board using a 64 item array. I found that this implementation was about 1/3 more efficient, at least in my case.

One of the things you want to consider when doing the [8][8] approach is describing positions. For example if you wish to describe a valid move for a chess piece, you will need 2 bytes to do so. While with the [64] item array you can do it with one byte.

To convert from a position on the [64] item board to a [8][8] board you can simply use the following calculations:

Row= (byte)(index / 8)

Col = (byte)(index % 8)

Although I found that you never have to do that during the recursive move searching which is performance sensitive.

For more information on building a chess engine, feel free to visit my blog that describes the process from scratch: www.chessbin.com

Adam Berent