派生类

#include<iostream>
#include<string>
using namespace std;
class Student
{
public:
    Student(int n,string nam)
    {
        num=n;
        name=nam;
    }

    void display()
    {
        cout<<"num:"<<num<<endl;
        cout<<"name:"<<name<<endl;

    }

protected:
    int num;
    string name;
};

class Student1:public Student
{
public :
    Student1(int n,string nam,int a):Student(n,nam)
    {
        age=a;
    }
    void show()
    {
        display();
        cout<<"age:"<<age<<endl;
    }

private:
    int age;
};

class Student2:public Student1
{
public:
    Student2(int n,string nam,int a,int s):Student1(n,nam,a)
    {
        score=s;
    }
    void show_all()
    {
        show();
        cout<<"score:"<<score<<endl;
    }

private:
    int score;
};

int main(){
    Student2 stud(10010,"Li",17,89);
    stud.show_all();
    return 0;
}