编辑代码

#include<iostream>
#include<string>
using namespace std;

//声明基类Student 
class Student                                                       
{
    public:
        Student(int, string, float); //声明构造函数
        virtual void display();      //声明虚函数，允许多态
    protected:                         //受保护成员,派生类可以访问 
        int num;
        string name;
        float score;
};

//Student类成员函数的实现
Student::Student(int n, string nam, float s) //定义构造函数
{num = n; name = nam; score = s;}
void Student::display()                      //定义输出函数
{cout << "num: " << num << "\nname: " << name << "\nscore: " << score << "\n\n";}

//声明公用派生类Graduate 
class Graduate : public Student
{
    public:
        Graduate(int, string, float, float); //声明构造函数
        void display();             //重写输出函数
    private:
        float wage;
};

//Graduate类成员函数的实现
Graduate::Graduate(int n, string nam, float s, float w) : Student(n, nam, s), wage(w) {}
void Graduate::display()                     //定义输出函数
{cout << "num: " << num << "\nname: " << name << "\nscore: " << score << "\nwage: " << wage << endl;}

//主函数
int main()
{
    Student stud1(1001, "Li", 87.5);  //定义Student类对象stud1
    Graduate grad1(2001, "Wang", 98.5, 1200); //定义Graduate类对象grad1
    Student *pt = &stud1;             //定义指向基类对象的指针变量pt, 指向stud1
    pt->display();                    //输出Student(基类)对象stud1中的数据

    pt = &grad1;                      //pt指向Graduate类对象grad1
    pt->display();                    //输出Graduate类对象grad1中的数据
    return 0;
}