text: #ifndef NOTEBOOK_H
  #define NOTEBOOK_H
  #include <iostream>
  #include <stdexcept>
  #include <map>
  using namespace std;
  #include "Direction.hpp"
  using ariel::Direction;
  struct defaultChar
  {
      char c = '_'; // this is the default value of each character types in our board
  };
  struct defaultRow
  {
      int c = 1; // this is the default value of each character types in our board
  };
  namespace ariel
  {
      class Notebook
      {
          map<int, map<int, defaultChar[100]>> notebook;
          map<int, defaultRow> maxRows;
          char deleted = '~';
  
      public:
          Notebook();
          void write(int page, int row, int column, Direction Dir, string const &str);
          string read(int page, int row, int column, Direction Dir, int count);
          void erase(int page, int row, int column, Direction Dir, int count);
          void show(int page);
      };
  }
  #endif