W3School TIY Editor

#include <iostream> using namespace std; class Animal { public: virtual void sound() { cout << "动物声音\n"; } }; class Dog : public Animal { public: void sound() override { cout << "狗吠叫\n"; } }; int main() { Animal* a; Dog d; a = &d; a->sound(); // 输出：狗吠叫 return 0; }