public static bool isMate(King king,
ChessPiece[,] positions)
{
for (int i = 0, rank = king.Rank - 1; i < 3;
i++, rank++)
{
for (int j = 0, file =
king.File - 1; j < 3;
j++, file++)
{
if (rank < 0 || rank > 7
|| file < 0
|| file > 7
|| rank == file)
continue;
if (king.
isValidMove (rank,
file,
positions,
ChessBoardConstants.
MOVE_EXCHANGE))
return false;
}
}
return true;
}