#include <iostream>
#include <string>
using namespace std;
namespace jixia
{
 class Book
 {
	int ID;       // 條碼
	string Name;  // 書名
	string Author;// 作者 
	string Price; // 價(jià)格
 public:
	Book(int IDs,string Names,string Authors,string Prices);
	~Book()  {}
	friend ostream& operator<<(ostream &o,Book &b);
    friend class Books;
	friend class Library;
 };
}