26.cpp

#include "E26.h"

// non-member function
istream &read(istream &is, Sales_data &item) {
	double price = 0;
	is >> item.bookNo >> item.units_sold >> price;
	item.revenue = price * item.units_sold;
	return is;
}

ostream &print(ostream &os, const Sales_data &item) {
	os << item.isbn() << " " << item.units_sold << " " << item.revenue;
	return os;
}

// member functions
Sales_data& Sales_data::combine(const Sales_data& rhs) {
	units_sold += rhs.units_sold;
	revenue += rhs.revenue;
	return *this;
} 

Sales_data::Sales_data(istream &is) {
	read(is, *this);
}


int main(){
    
}