sales_item.h

#ifndef SALESITEM_H

#define SALESITEM_H

#include <iostream>

#include <string>

 

 

class Sales_item

{

public:

     Sales_item(const std::string &book):isbn(book),units_sold(0),revenue(0.0){}

     Sales_item(std::istream &is){ is >> *this;}

     friend std::istream& operator>>(std::istream &,Sales_item &);

     friend std::ostream& operator<<(std::ostream &,const Sales_item &);

public:

     Sales_item & operator+=(const Sales_item&);

public:

     double avg_price() const;

     bool same_isbn(const Sales_item &rhs)const

     {

         return isbn == rhs.isbn;

     }

     Sales_item():units_sold(0),revenue(0.0){}

public:

     std::string isbn;

     unsigned units_sold;

     double revenue;

};

 

using std::istream;

using std::ostream;

Sales_item operator+(const Sales_item &,const Sales_item &);

inline bool operator==(const Sales_item &lhs,const Sales_item &rhs)

{

     return lhs.units_sold == rhs.units_sold && lhs.revenue == rhs.revenue && lhs.same_isbn(rhs);

}

inline bool operator!=(const Sales_item &lhs,const Sales_item &rhs)

{

     return !(lhs == rhs);

}

 

inline Sales_item & Sales_item::operator +=(const Sales_item &rhs)

{

     units_sold += rhs.units_sold;

     revenue += rhs.revenue;

     return *this;

}

inline Sales_item operator+(const Sales_item &lhs,const Sales_item &rhs)

{

     Sales_item ret(lhs);

     ret += rhs;

     return ret;

}

inline istream& operator>>(istream &in,Sales_item &s)

{

     double price;

     in >> s.isbn >> s.units_sold >> price;

     if(in)

         s.revenue = s.units_sold * price;

     else

         s = Sales_item();

     return in;

}

inline ostream& operator<<(ostream &out,const Sales_item &s)

{

     out << s.isbn << "/t" <<s.units_sold << "/t" << s.revenue << "/t" << s.avg_price();

     return out;

}

inline double Sales_item::avg_price() const

{

     if(units_sold)

         return revenue/units_sold;

     else

         return 0;

}

#endif