// Declaration of class Board, used by knights tour program
// bds 11/98
#include <stdlib.h>
#include <iostream.h>

/* a knight at position (x,y) can legally move to position
   (x + xstep[ i ], y + ystep[ i ] ), for i = 0, 1, ..., 7, provided
   that position is on the board and not occupied by another piece of 
   the same player */
const int xstep[8] = { 1,  1,  2,  2, -1 , -1, -2, -2 };
const int ystep[8] = { 2, -2,  1, -1,  2 , -2,  1, -1 };
// remark: rather than global, these should be static members of class Board

class Board {
 public: 
  int goal;  // the number of squares to be filled
  int last;  // the number of pieces on board (and index to last position). 

  Board(int m, int n); // construct a m by n board

  int validMove( int i ); // true if move number i is a valid move 
		          // on current configuration.

  void extend( int i ); // add move i to current configuration.  Must be valid.

  void unextend(); // remove last move;

 private:
  int rows;  // number of rows on this board
  int cols;  // number of columns on this board
  int* x; // array of x-coordinates of the pieces on board in order placed
  int* y; // array of y-coordinates of the knights on board in order placed
  int** board; // 2 dim array representing board

}; // class Board declaration