ifndefPOSITION.docVIP

#ifndef POSITION #define POSITION class Position { ?? ?protected: ?? ? ? ?int row,column; ?? ?public: ?? ? ? ?Position(); ?? ? ? ?Position (int row, int column); ?? ? ? ?int getRow() const; ?? ? ? ?int getColumn() const; int getnum_of_queen() const; void setPosition(int newRow,int newColumn); }; // class Position #endif #ifndef BACKTRACK #define BACKTRACK #include Application.h; #include Position.h; class BackTrack ? { ?? ?public: ?? ? ? ?BackTrack (const Application app); ?? ? ? ?bool tryToSolve (Position pos); ?? ?protected: ?? ? ? ?Application app; }; // class BackTrack #endif #ifndef APPLICATION #define APPLICATION #include iostream #include Position.h using namespace std; class Application { ?? ?friend ostream operator(ostream stream, Application app); ?? ?public: ?? ? ? ?// Postcondition: the initial state for this Application has been ?? ? ? ?// ? ? ? ? ? ? ? ?generated -- from input or assignments -- and ?? ? ? ?// ? ? ? ? ? ? ? ?the start position has been returned. ?? ? ? ?Position generateInitialState(); ?? ? ? ?// Postcondition: true has been returned if pos can be on the path ?? ? ? ?// ? ? ? ? ? ? ? ?to a goal. ?Otherwise, false has been returned. ?? ? ? ?bool valid (const Position pos); ?? ? ? ?// Precondition: pos represents a valid position. ?? ? ? ?// Postcondition: pos has been recorded as a valid position. ?? ? ? ?void record (const Position pos); ?? ? ? ?// Postcondition: true has been returned if pos is the final ?? ? ? ?// ? ? ? ? ? ? ? ?position for this application. ?Otherwise, false ?? ? ? ?// ? ? ? ? ? ? ? ?has been returned. ?? ? ? ?bool done () const; ?? ? ? ?// Postcondition: pos has been marked as not being on the path to ?? ? ? ?// ? ? ? ? ? ? ? ?a goal. ?? ? ? ?void undo (const Position pos); ? ? ? ?? ?class Iterator ?? ?{ protected: ?? ? ? ? ? ?void* fieldPtr; ?? ? ? ?public: ?? ? ? ? ? ?// Postcondition: this Iterator has been initialized to ?? ? ? ? ? ?// ? ? ? ? ? ? ? ?iterate from pos. ?? ? ? ? ? ?Iterator (const Position