C++ Primer, Fifth Edition

1.6. The Bookstore Program

We are now ready to solve our original bookstore problem. We need to read a file of sales transactions and produce a report that shows, for each book, the total number of copies sold, the total revenue, and the average sales price. We’ll assume that all the transactions for each ISBN are grouped together in the input.

Our program will combine the data for each ISBN in a variable named total. We’ll use a second variable named trans to hold each transaction we read. If trans and total refer to the same ISBN, we’ll update total. Otherwise we’ll print total and reset it using the transaction we just read:

#include <iostream>#include "Sales_item.h"int main(){    Sales_item total; // variable to hold data for the next transaction ...