4.19

#include<iostream>  
using namespace std;  
class book  
{
private:
 int qu;  
 int price;  
public:  
 book(int q,int p)  
 {  
  qu=q;  
  price=p;  
 }  
 void print()  
 {  
  cout<<qu*price<<endl;  
 }  
};
int main()  
{  
 book b[5]={book(1,10),book(2,20),book(3,30),book(4,40),book(5,50)};  
 for(int i=0;i<5;i++)  
 b[i].print();  
 return 0;  
}