//
// ex14_13.cpp
// Exercise 14.13
//
// Created by pezy on 3/9/15.
// Substraction and compound-substraction operations added by hoeselm on 4/10/16.
//
// @Brief implementation of class Sales_data
// @See ex14_13.h

#include "ex14_13.h"

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

Sales_data& Sales_data::operator+=(const Sales_data &rhs)
{
 units_sold += rhs.units_sold;
 revenue += rhs.revenue;
 return *this;
}


Sales_data& Sales_data::operator-=(const Sales_data &rhs)
{
 units_sold -= rhs.units_sold;
 revenue -= rhs.revenue;
 return *this;
}

std::istream& operator>>(std::istream &is, Sales_data &item)
{
 double price = 0.0;
 is >> item.bookNo >> item.units_sold >> price;
 if (is)
 item.revenue = price * item.units_sold;
 else
 item = Sales_data();
 return is;
}

std::ostream& operator<<(std::ostream &os, const Sales_data &item)
{
 os << item.isbn() << " " << item.units_sold << " " << item.revenue << " " << item.avg_price();
 return os;
}

Sales_data operator+(const Sales_data &lhs, const Sales_data &rhs)
{
 Sales_data sum = lhs;
 sum += rhs;
 return sum;
}

Sales_data operator-(const Sales_data &lhs, const Sales_data &rhs)
{
 Sales_data sum = lhs;
 sum -= rhs;
 return sum;
}