Modern C++ Design Pattern/Chatper 8. 컴포지트

  class Creature
  {
    int strength, agility, intelligence;
  public:
    int get_stringth() const
    {
      return strength;
    }

    void set_strength(int strength)
    {
      Creture::strength = strength;
    }
    // Other getter/setter....
    int sum() const {
      return strength + agility + intelligence;
    }

    double average() const {
      return sum() / 3.0;
    }

    int max() const {
      return ::max(::max(strength, agility), intelligence);
    }
  };

  class Creature
  {
    enum Abilitis { str, agl, intl, count };
    array<int, count> abilities;
    int get_strength() const { return abilities[str]; }
    void set_strength(int value) { abilities[str] = value; }
    // Other getter/setter ...

    int sum() const {
      return accumulate(abilities.begin(), abilities.end(), 0);
    }

    double average() const {
      return sum() / (double) count;
    }

    int max() const {
      return *max_element(abilities.begin(), abilities.end());
    }
  };

  struct GraphicObject
  {
    virtual void draw() = 0;
  };

  struct Circle : GraphicObject
  {
    void draw() override
    {
      cout << "Circle" << endl;
    }
  };

  struct Group : GraphicObject
  {
    string name;

    explicit Group(const string& name)
      : name{name} {}

    void draw() override
    {
      cout << "Group " << name.c_str() << " containes:" << endl;
      for (auto&& o : objects)
        o->draw();
    }

    vector<GraphicObject*> objects;
  };

  Group root("root");
  Circle c1, c2;
  root.objects.push_back(&c1);

  Group subgroup("sub");
  subgroup.objects.push_back(&c2);

  root.objects.push_back(&subgroup);

  root.draw();