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#include "Sales_item.h"
#include <iostream>
#include <string>
using namespace std;
inline
Sales_item operator+(const Sales_item& lhs, const Sales_item& rhs)
{
Sales_item ret(lhs); // copy lhs into a local object that we'll return
ret += rhs; // add in the contents of rhs
return ret; // return ret by value
}
inline
bool operator==(const Sales_item &lhs, const Sales_item &rhs)
{
// must be made a friend of Sales_item
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); // != defined in terms of operator==
}
using std::istream; using std::ostream;
// assumes that both objects refer to the same isbn
inline
Sales_item& Sales_item::operator+=(const Sales_item& rhs)
{
units_sold += rhs.units_sold;
revenue += rhs.revenue;
return *this;
}
// assumes that both objects refer to the same isbn
inline
istream& operator>>(istream& in, Sales_item& s)
{
double price;
in >> s.isbn >> s.units_sold >> price;
// check that the inputs succeeded
if (in)
s.revenue = s.units_sold * price;
else
s = Sales_item(); // input failed: reset object to default state
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;
}