1. Best Free Chess Programs

I'm supposed to be writing a program for a programming class that involves taking an infinitely scalable chess board, and randomly placing queen pieces on it in such a way that no two can take each other. I've got almost all of my code busted out, it displays and all, but I keep getting an issue where one of. Hi I need to make a chess board and I'm pretty stuck m gives the thickness of the square and n th size Code: #include void main() { in.

Initially, use an 8. 8 integer array to represent the chess board.

You can start programing using this notation. Give point values for the pieces. For example:.White.

9 = white queen 5 = white rook 3 = bishop 3 = knight 1 = pawn.black.9 = white queen -5 = white rook -3 = bishop -3 = knight -1 = pawn White King: very large positive number Black King: very large negative number etc. (Note that the points given above are approximations of trading power of each chess piece) After you develop the basic backbones of your application and clearly understand the working of the algorithms used, try to improve the performance by using bit boards. In bit boards, you use eight 8 -bit words to represent the boards. This representation needs a board for each chess piece.

In one bit board you will be storing the position of the rook while in another you will be storing the position of the knight. Etc Bit boards can improve the performance of your application very much because manipulating the pieces with bit boards are very easy and fast. As you pointed out, Most chessprograms today, especially those that run on a 64 bit CPU, use a bitmapped approach to represent a chessboard and generate moves. X88 is an alternate board model for machines without 64 bit CPUs. For a serious chess engine, using bitboards is an efficient way to represent a chess board in memory. Bitboards are faster than any array based representation, specially in 64-bit architectures where a bitboard can fit inside a single CPU register.

Bitboards Basic idea of bitboards is to represent every chess piece type in 64 bits. In C/C# it will be ulong/UInt64. So you'll maintain 12 UInt64 variables to represent your chess board: two (one black and one white) for each piece type, namely, pawn, rook, knight, bishop, queen and king. Every bit in a UInt64 will correspond to a square on chessboard. Typically, the least significant bit will be a1 square, the next b1, then c1 and so on in a row-major fashion.

The bit corresponding to a piece's location on chess board will be set to 1, all others will be set to 0. For example, if you have two white rooks on a2 and h1 then the white rooks bitboard will look like this: 0000 Now for example, if you wanted to move your rook from a2 to g2 in the above example, all you need to do is XOR you bitboard with: 0000 Bitboards have a performance advantage when it comes to move generation. There are other performance advantages too that spring naturally from bitboards representation. For example you could use which are an immense advantage when parallelising your search algorithm. Further Reading The ultimate resource for chess engine development is the. I've recently written which implements bitboards in C#. An even better open source chess engine is which also implements bitboards but in C.

The simple approach is to use an 8x8 integer array. Use 0 for empty squares and assign values for the pieces: 1 white pawns 2 white knights 3 white bishops 4 white rooks 5 white queens 6 white king Black pieces use negative values -1 black pawn -2 black knight etc 8 -4 -2 -3 -5 -6 -3 -2 -4 7 -1 -1 -1 -1 -1 -1 -1 -1 6 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 2 1 1 1 1 1 1 1 1 1 4 2 3 5 6 3 2 4 - 1 2 3 4 5 6 7 8 Piece moves can be calculated by using the array indexes. For example the white pawns move by increasing the row index by 1, or by 2 if it's the pawn's first move. So the white pawn on 21 could move to 31 or 41. However this simple 8x8 array representation of has chessboard has several problems. Most notably when you're moving 'sliding' pieces like rooks, bishops and queens you need to constantly be checking the indexes to see if the piece has moved off the board.

Most chessprograms today, especially those that run on a 64 bit CPU, use a bitmapped approach to represent a chessboard and generate moves. X88 is an alternate board model for machines without 64 bit CPUs.

When creating my chess engine I originally went with the 88 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 88 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 88 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: Adam Berent.

There are of course a number of different ways to represent a chessboard, and the best way will depend on what is most important to you. Your two main choices are between speed and code clarity. If speed is your priority then you must use a 64 bit data type for each set of pieces on the board (e.g.

White pawns, black queens, en passant pawns). You can then take advantage of native bitwise operations when generating moves and testing move legality. If clarity of code is priority then forget bit shuffling and go for nicely abstracted data types like others have already suggested. Just remember that if you go this way you will probably hit a performance ceiling sooner. To start you off, look at the code for (C) and (C#). I know this is a very old post which I have stumbled across a few times when googling chess programming, yet I feel I must mention it is perfectly feasible to model a chessboard with a 1D array e.g.

Chessboard64; I would say this is the simplest approach to chessboard representation.but of course it is a basic approach. Is a 1D chessboard array structure more efficient than a 2D array (which needs a nested for loop to access and manipulate the indices)? It is also possible to use a 1D array with more than 64 squares to represent OffBoard squares also e.g. Chessboard120; (with the array sentinel and board playing squares correctly initialised).

Finally and again for completeness for this post I feel I must mention the 0x88 board array representation. This is quite a popular way to represent a chessboard which also accounts for offboard squares.

Initially, use an 8. 8 integer array to represent the chess board. You can start programing using this notation. Give point values for the pieces.

For example:.White. 9 = white queen 5 = white rook 3 = bishop 3 = knight 1 = pawn.black.9 = white queen -5 = white rook -3 = bishop -3 = knight -1 = pawn White King: very large positive number Black King: very large negative number etc. (Note that the points given above are approximations of trading power of each chess piece) After you develop the basic backbones of your application and clearly understand the working of the algorithms used, try to improve the performance by using bit boards. In bit boards, you use eight 8 -bit words to represent the boards.

This representation needs a board for each chess piece. In one bit board you will be storing the position of the rook while in another you will be storing the position of the knight. Etc Bit boards can improve the performance of your application very much because manipulating the pieces with bit boards are very easy and fast. As you pointed out, Most chessprograms today, especially those that run on a 64 bit CPU, use a bitmapped approach to represent a chessboard and generate moves. X88 is an alternate board model for machines without 64 bit CPUs.

For a serious chess engine, using bitboards is an efficient way to represent a chess board in memory. Bitboards are faster than any array based representation, specially in 64-bit architectures where a bitboard can fit inside a single CPU register. Bitboards Basic idea of bitboards is to represent every chess piece type in 64 bits. In C/C# it will be ulong/UInt64. So you'll maintain 12 UInt64 variables to represent your chess board: two (one black and one white) for each piece type, namely, pawn, rook, knight, bishop, queen and king. Every bit in a UInt64 will correspond to a square on chessboard.

Typically, the least significant bit will be a1 square, the next b1, then c1 and so on in a row-major fashion. The bit corresponding to a piece's location on chess board will be set to 1, all others will be set to 0. For example, if you have two white rooks on a2 and h1 then the white rooks bitboard will look like this: 0000 Now for example, if you wanted to move your rook from a2 to g2 in the above example, all you need to do is XOR you bitboard with: 0000 Bitboards have a performance advantage when it comes to move generation. There are other performance advantages too that spring naturally from bitboards representation. For example you could use which are an immense advantage when parallelising your search algorithm. Further Reading The ultimate resource for chess engine development is the.

I've recently written which implements bitboards in C#. An even better open source chess engine is which also implements bitboards but in C. The simple approach is to use an 8x8 integer array. Use 0 for empty squares and assign values for the pieces: 1 white pawns 2 white knights 3 white bishops 4 white rooks 5 white queens 6 white king Black pieces use negative values -1 black pawn -2 black knight etc 8 -4 -2 -3 -5 -6 -3 -2 -4 7 -1 -1 -1 -1 -1 -1 -1 -1 6 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 2 1 1 1 1 1 1 1 1 1 4 2 3 5 6 3 2 4 - 1 2 3 4 5 6 7 8 Piece moves can be calculated by using the array indexes.

For example the white pawns move by increasing the row index by 1, or by 2 if it's the pawn's first move. So the white pawn on 21 could move to 31 or 41. However this simple 8x8 array representation of has chessboard has several problems. Most notably when you're moving 'sliding' pieces like rooks, bishops and queens you need to constantly be checking the indexes to see if the piece has moved off the board. Most chessprograms today, especially those that run on a 64 bit CPU, use a bitmapped approach to represent a chessboard and generate moves.

X88 is an alternate board model for machines without 64 bit CPUs. When creating my chess engine I originally went with the 88 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 88 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 88 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: Adam Berent. There are of course a number of different ways to represent a chessboard, and the best way will depend on what is most important to you. Your two main choices are between speed and code clarity. If speed is your priority then you must use a 64 bit data type for each set of pieces on the board (e.g.

White pawns, black queens, en passant pawns). You can then take advantage of native bitwise operations when generating moves and testing move legality.

If clarity of code is priority then forget bit shuffling and go for nicely abstracted data types like others have already suggested. Just remember that if you go this way you will probably hit a performance ceiling sooner. To start you off, look at the code for (C) and (C#).

Best Free Chess Programs

I know this is a very old post which I have stumbled across a few times when googling chess programming, yet I feel I must mention it is perfectly feasible to model a chessboard with a 1D array e.g. Chessboard64; I would say this is the simplest approach to chessboard representation.but of course it is a basic approach.

Is a 1D chessboard array structure more efficient than a 2D array (which needs a nested for loop to access and manipulate the indices)? It is also possible to use a 1D array with more than 64 squares to represent OffBoard squares also e.g. Chessboard120; (with the array sentinel and board playing squares correctly initialised). Finally and again for completeness for this post I feel I must mention the 0x88 board array representation. This is quite a popular way to represent a chessboard which also accounts for offboard squares.