在通过值传递对象时防止切片(继承)

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

class Derived : public Base {
public:
    void display() const override {
        std::cout << "Derived class" << std::endl;
    }
    void newFeature() const {
        std::cout << "New feature in Derived class" << std::endl;
    }
};

void printObject(const Base& obj) {
    obj.display();
}

int main() {
    Derived d;
    printObject(d); // 调用的是Derived类的display方法
    return 0;
}

void printObject(Base* obj) {
    obj->display();
}

int main() {
    Derived d;
    printObject(&d); // 调用的是Derived类的display方法
    return 0;
}