#include <iostream>

#include <string>using namespace std;

class Book

{ public:Book(string na, string au, int page, float price):name(na),author(au),page(page),price(price){ cout<<"书名："<<name<<endl<<"作者："<<author<<endl<<"页数："<<page<<endl<<"价格："<<price<<endl;}

Book(string na, string au):    name(na),author(au){    cout<<"书名："<
    
     <
     
      <<"作者："<
      
       <
      
     
    

};

int main()

{ Book b1("sa","zero",12,34);Book b2("sa","zero");Book b3; return 0;}