#ifndef DIGIT_H
#define DIGIT_H

#include "param.h"

class Digit {
friend ostream& operator<< (ostream &, Digit &);
friend istream& operator>> (istream &, Digit &);
public:
  Digit();
  Digit(int);
  ~Digit();
  int getvalue();
  void setdigit(int);
  void display();
  void showcell(int, int);
  void operator=(int);
  void operator+=(Digit);
  void operator-=(Digit);
  Digit operator+(Digit);
  Digit operator-(Digit);
  bool operator==(Digit);
  bool operator!=(Digit);
  bool operator<=(Digit); 
  bool operator<(Digit);
  bool operator>=(Digit); 
  bool operator>(Digit);
  Digit operator++();
  Digit operator--();
  bool isvalid();
private:
  void setvalue(int);
  void setgrid(int);
  int value;
  char grid[ROWS][COLS];
};

#endif