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

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. chessboard[64];

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. chessboard[120]; (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.