state design pattern for sql recordset function

Question

I have to implement state design pattern in c++ for sql recordset

I would like to implement movefirst(),moveNext(),movelast(),movePrevious() function in c++

RecExtractionSystem.h:

class RecExtractionSystem
{
    States *m_CurrentState;
        public:
            RecExtractionSystem();
             bool ProcessCurrentRec();
             bool ProcessNextRec();
             bool ProcessFirstRec();
             bool ProcessPrevRec();
             bool ProcessLastRec();
             void SetCurrentState(States* currentState);
};

States.h:

class States
{
public:
      virtual bool ProcessCurrentRec(RecExtractionSystem *pRecExtractionSystem);
      virtual bool ProcessNextRec(RecExtractionSystem *pRecExtractionSystem);
      virtual bool ProcessFirstRec(RecExtractionSystem *pRecExtractionSystem);
      virtual bool ProcessPrevRec(RecExtractionSystem *pRecExtractionSystem);

      virtual bool ProcessLastRec(RecExtractionSystem *pRecExtractionSystem);
};

class StopProcessingRec: public States
{
public:
       bool ProcessCurrentRec(RecExtractionSystem *pRecExtractionSystem);
};

class ProcessinCurrentRec: public States
{
public:


    bool ProcessFirstRec(RecExtractionSystem *pRecExtractionSystem);
    bool ProcessNextRec(RecExtractionSystem *pRecExtractionSystem);
    bool ProcessPrevRec(RecExtractionSystem *pRecExtractionSystem);

    bool ProcessLastRec(RecExtractionSystem *pRecExtractionSystem);
};

Void main()
{
      RecExtractionSystem *pRecExtractionSystem = new RecExtractionSystem(); 
            pRecExtractionSystem->ProcessNextRec();

}

When I call the ProcessNextRec(), it is calling the function of

State::ProcessNextRec()

But it should call the

ProcessinCurrentRec::ProcessNextRec().

What is wrong here?

Answer 1

You'll need to add the override key to each virtual function you reimplement from the base class

https://en.cppreference.com/w/cpp/language/override

class ProcessinCurrentRec: public States
{
public:

  bool ProcessNextRec(RecExtractionSystem *pRecExtractionSystem) override;

};