C++从父类获取子类

#include <iostream>

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

class Derived : public Base {
public:
    void display() override {
        std::cout << "Display from Derived class" << std::endl;
    }

    void showExtra() {
        std::cout << "Extra feature in Derived class" << std::endl;
    }
};

int main() {
    Base* basePtr = new Derived();
    basePtr->display(); // 调用的是Derived类的display方法

    // 如果需要调用Derived类的特定方法，需要进行类型转换
    Derived* derivedPtr = dynamic_cast<Derived*>(basePtr);
    if (derivedPtr) {
        derivedPtr->showExtra();
    } else {
        std::cout << "Cast failed!" << std::endl;
    }

    delete basePtr;
    return 0;
}

Derived* derivedPtr = dynamic_cast<Derived*>(basePtr);
if (derivedPtr) {
    derivedPtr->showExtra();
}