Mine

class Elections {
      
      public: 
              void ReadData();        
              void CalculateAndPrintResults();
              
      private:
              
              PartyDB parties;
              VoterDB voters;
              BallotVec ballots;
              
}; 

class PartyDB {
      
      public:
             
             void AddParty(const string& id);
             void RemoveParty(const string& id);
             Party* GetPartyByName(const string& id);
             Party* GetPartyByIndex(unsigned int index);
             unsigned int PartyCount() const;
             ~PartyDB();             
             
      private:
              
             PartyVec parties; 
};