#include<iostream>
#include"Sales_item.h"
int main()
{
	Sales_item total,book;
	std::cout<<"enter some transactions:"<<std::endl;
	if(std::cin>>total)
	{
		while(std::cin>>book)
		{

			if(total.same_isbn(book))
			{
				total+=book;
			}
			else
			{
				std::cout<<"have different isbn"<<std::endl;
				return 1;
			}
		}
		std::cout<<"ISBN,number of copies sold,"
			<<"total revenue,and average price are:"
			<<std::endl<<total;
	}
	else
	{
		std::cout<<"no data"<<std::endl;
     	return -1;
	}
return 0;

}