다형성은 C++에서 위임 및 이벤트 처리를 어떻게 지원합니까?

#include <iostream>

using namespace std;

class Base {
public:
  virtual void print() const { cout << "Base" << endl; }
};

class Derived : public Base {
public:
  void print() const override { cout << "Derived" << endl; }
};

int main() {
  Base* b = new Derived();  // 多态性：Base 指针可以指向 Derived 对象
  b->print();  // 调用派生类函数
  return 0;
}

#include <iostream>

using namespace std;

class Button {
public:
  void click() const { if (_listener) _listener->buttonClicked(); }
  void setListener(ButtonListener* listener) { _listener = listener; }
private:
  ButtonListener* _listener = nullptr;
};

class ButtonListener {
public:
  virtual void buttonClicked() {}
};

class Form {
public:
  Form() : _button(new Button()) {}
  void setButtonListener(ButtonListener* listener) { _button->setListener(listener); }
private:
  Button* _button;
};

class MyListener : public ButtonListener {
public:
  void buttonClicked() override { cout << "Button clicked!" << endl; }
};

int main() {
  Form form;
  form.setButtonListener(new MyListener());
  form._button->click();
  return 0;
}