实验5

task4：

pets.hpp:

#pragma once
#include<iostream>
#include<string>
using namespace std;
class MachinePets {
public:
    MachinePets(){ }
    MachinePets(const string s) :nickname(s) { }
    string get_nickname() const {
        return nickname;
    }
    virtual string talk()=0;
    
    string nickname;
};
 
class PetDogs:public MachinePets {
public:
    PetDogs(const string s):MachinePets(s){ }
    string talk() {
        return "wang wang~";
    }
};

class PetCats:public MachinePets {
public:
    PetCats(const string s) :MachinePets(s) { }
    string talk() {
        return "miao wu~";
    }
};

task4.cpp:

#include <iostream>
#include "pets.hpp"
 
void play(MachinePets& obj) {
    std::cout << obj.get_nickname() << " says " << obj.talk() << std::endl;
}
 
void test() {
    PetCats cat("miku");
    PetDogs dog("da huang");
 
    play(cat);
    play(dog);
}
 
int main() {
    test();
}

截图：

task5：

Person.hpp:

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

class Person{
    public:
        Person(){}
        Person(string s1,string s2,string s3=" "):name(s1),telephone(s2),email(s3){}
        Person(Person const &p):name(p.name),telephone(p.telephone),email(p.email){}
        
        void update_telephone(){
            cout<<"tel";
            cin.clear();
            cin>>telephone;
        }    
        
        void update_email(){
            cout<<"ema";
            cin.clear();
            cin>>email;
        }
        
        friend bool operator==( Person& a,  Person& b);
        
        friend ostream& operator<<(ostream &out,  Person &c);
        
        friend istream& operator>>(istream &in, Person &c);
        
    private:
        string name,telephone,email;    
};

bool operator==( Person &a,  Person &b)
{
    return (a.name==b.name && a.telephone==b.telephone);
}

ostream& operator<<(ostream &out, Person &c)
{
    out << c.name << "\t" << c.telephone << "\t" << c.email;
    return out;
}

istream& operator>>(istream &in, Person &c)
{
    in >> c.name;
    in >> c.telephone;
    in >> c.email;
    return in;
}

task5.cpp:

#include <iostream>
#include <fstream>
#include <vector>
#include "Person.hpp"
 
void test() {
    using namespace std;
 
    vector<Person> phone_book;
    Person p;
 
    cout << "Enter person's contact until press Ctrl + Z" << endl;
    while (cin >> p)
        phone_book.push_back(p);
 
    cout << "\nupdate someone's contact: \n";
    phone_book.at(0).update_telephone();
    phone_book.at(0).update_email();
 
    cout << "\ndisplay all contacts' info\n";
    for (auto& phone : phone_book)
        cout << phone << endl;
 
    cout << "\ntest whether the same contact\n";
    cout << boolalpha << (phone_book.at(0) == phone_book.at(1)) << endl;
}
 
int main() {
    test();
}

截图：

task6:

= =

被保护的数据类外无法访问，我不太知道该怎么修改。