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#ifndef SALESITEM_H
#define SALESITEM_H
#include <iostream>
#include <string>
class Sales_item
{
friend
bool operator==(const Sales_item&, const 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&);
Sales_item& operator+=(const Sales_item&);
double avg_price() const;
bool same_isbn(const Sales_item &rhs) const
{
return isbn == rhs.isbn;
}
Sales_item(): units_sold(0), revenue(0.0)
{
}
private:
std::string isbn;
unsigned units_sold;
double revenue;
};
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);
}
using std::istream; using std::ostream;
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