虚函数基础写法

题目描述

补全 Base 类的定义，使得程序符合下文规定的输入输出行为。

关于输入

无

关于输出

见样例输出

核心技巧

• 不声明虚函数时，按照变量声明类型确定访问对象。

参考答案

#include <iostream>

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

class Derived : public Base {
public:
    void f() {
        std::cout << "Derived::f" << std::endl;
    }
    void g() {
        std::cout << "Derived::g" << std::endl;
    }
};

int main() {
    Base* ptr1 = new Base{};
    ptr1->f();
    ptr1->g();
    delete ptr1;

    Base* ptr2 = new Derived{};
    ptr2->f();
    ptr2->g();
    delete ptr2;

    auto obj3 = Derived{};
    obj3.f();
    obj3.g();
}