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

class Book
{
private:
	string name;//书名
	string no;//书号
public:
	Book();
	Book(string name,string no);
	Book(Book& s);
	string Getname(){return name;};
	string Getno(){return no;};
};

Book::Book()
{
	name = "默认书";
	no = "0";
}

Book::Book(string name,string no)
{
	this->name=name;
	this->no=no;
}

Book::Book(Book& s)
{
	this->name=s.name;
	this->no=s.no;
}


class Teach:public Book
{
private:
	string obj;//科目
public:
	
	Teach();
	Teach(string name,string no,string c);
	void Print_Info();
	friend ostream& operator<<(ostream &out, Teach &per)
	{
		out<<per.Getname().c_str()<<' '<<per.Getno().c_str()<<' '<<per.Getobj().c_str()<<endl;
		return out;
	}
	string Getobj(){return obj;};
};


Teach::Teach()
{
	obj="无";
}

Teach::Teach(string name,string no,string c):Book(name,no)
{
	obj=c;
}

void Teach::Print_Info()
{
	cout<<"科目:"<<obj<<endl;
}

int main()
{
	Teach a;
	Teach b("计网","123","计算机");
	Teach c("1","2","3");

	ofstream fout;
	fout.open("data.txt",ios::app);
	fout<<a; 
	fout<<b; 
	fout<<c; 
	fout.close();

	return 0;
}