C++ 연계, 제휴 관계 (Association)

연계, 제휴 관계 (Association)

• 의사 클래스와 환자 클래스로 비유

  #include <iostream>
  #include <vector>
  
  using namespace std;
  
  class Doctor;
  
  class Patient
  {
    string            name_;
    vector<Doctor*>    doctors_;
  
  public:
    Patient(const string &name_in)
      : name_{name_in}
    {}
  
    void    addDoctor(Doctor* new_doctor)
    {
      doctors_.push_back(new_doctor);
    }
  
    void    meetDoctors();
  
    friend class Doctor;
  };
  
  class Doctor
  {
    string                name_;
    vector<Patient*>    patients_;
  
  public:
    Doctor(const string &name_in)
      : name_{name_in}
    {}
  
    void    addPatient(Patient* new_patient)
    {
      patients_.push_back(new_patient);
    }
  
    void    meetPatients()
    {
      for (auto& e : patients_)
        cout << "Meet patient : " << e->name_ << '\n';
    }
  
    friend class Patient;
  };
  
  void    Patient::meetDoctors()
  {
    for (auto& e : doctors_)
      cout << "Meet doctor : " << e->name_ << '\n';
  }
  
  int        main()
  {
    Patient* p1 = new Patient("Jack Jack");
    Patient* p2 = new Patient("Dash");
    Patient* p3 = new Patient("Violet");
  
    Doctor* d1 = new Doctor("Doctor K");
    Doctor* d2 = new Doctor("Doctor L");
  
    p1->addDoctor(d1);
    d1->addPatient(p1);
  
    p2->addDoctor(d2);
    d2->addPatient(p2);
  
    p2->addDoctor(d1);
    d1->addPatient(p2);
  
    cout << "p1\n";
    p1->meetDoctors();
  
    cout << "\nd1\n";
    d1->meetPatients();
  
    delete p1, p2, p3, d1, d2;
  
  }
  
  /* stdout
  p1
  Meet doctor : Doctor K
  
  d1
  Meet patient : Jack Jack
  Meet patient : Dash
  */