使用友元函数从多态类中检索类型信息？

class Base {
public:
    virtual ~Base() {}
    friend void GetType(const Base* obj);
};

void GetType(const Base* obj) {
    if (dynamic_cast<const Derived1*>(obj)) {
        std::cout << "Object is of type Derived1" << std::endl;
    } else if (dynamic_cast<const Derived2*>(obj)) {
        std::cout << "Object is of type Derived2" << std::endl;
    } else {
        std::cout << "Object is of unknown type" << std::endl;
    }
}

class Derived1 : public Base {
public:
    void PrintType() const {
        GetType(this);
    }
};

class Derived2 : public Base {
public:
    void PrintType() const {
        GetType(this);
    }
};

int main() {
    Base* obj1 = new Derived1();
    Base* obj2 = new Derived2();

    obj1->PrintType();  // Output: Object is of type Derived1
    obj2->PrintType();  // Output: Object is of type Derived2

    delete obj1;
    delete obj2;

    return 0;
}