4.20

#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)};   book *p; p=b; for(int i=4;i>=0;i--)   (p+i)->print();   return 0;  }