ACM输入输出--保护继承

#include <iostream>
using namespace std;
class Student
{
public:
    void get_value()
    {
        cin>>num>>name>>sex;
    }
    void display( )
    {
        cout<<"num: "<<num<<endl;
        cout<<"name: "<<name<<endl;
        cout<<"sex: "<<sex<<endl;
    }
private :
    int num;
    string name;
    char sex;
};
class Student1:public Student
{
    public:
    void get_value1()
    {
        get_value();
        cin>>age>>address;
    }
    void display1()
    {
        display();
        cout<<"age: "<<age<<endl;
        cout<<"address: "<<address<<endl;
    }
    private:
    int age;
    string address;
};
/* C++代码 */
int main()
{
    Student1 stud1;
    stud1.get_value1();
    stud1.display1();
    return 0;
}