1 #ifndef SALES_DATA_H

 2 #define SALES_DATA_H

 3

 4 #include "Version_test.h"

 5

 6 #include <string>

 7

 8 struct Sales_data {

 9     std::string bookNo;

10 #ifdef IN_CLASS_INITS

11     unsigned units_sold = 0;

12     double revenue = 0.0;

13 #else

14     unsigned units_sold;

15     double revenue;

16 #endif

17 };

18 #endif

 1 #include <iostream>

 2 #include <string>

 3 #include "Sales_data.h"

 4

 5 int main()

 6 {

 7     Sales_data data1, data2;

 8

 9     // code to read into data1 and data2

10     double price = 0;  // price per book, used to calculate total revenue

11

12     // read the first transactions: ISBN, number of books sold, price per book

13     std::cin >> data1.bookNo >> data1.units_sold >> price;

14     // calculate total revenue from price and units_sold

15     data1.revenue = data1.units_sold * price;

16

17     // read the second transaction

18     std::cin >> data2.bookNo >> data2.units_sold >> price;

19     data2.revenue = data2.units_sold * price;

20

21     // code to check whether data1 and data2 have the same ISBN

22     //        and if so print the sum of data1 and data2

23     if (data1.bookNo == data2.bookNo) {

24         unsigned totalCnt = data1.units_sold + data2.units_sold;

25         double totalRevenue = data1.revenue + data2.revenue;

26

27         // print: ISBN, total sold, total revenue, average price per book

28         std::cout << data1.bookNo << " " << totalCnt

29                   << " " << totalRevenue << " ";

30         if (totalCnt != 0)

31             std::cout << totalRevenue/totalCnt << std::endl;

32         else

33             std::cout  << "(no sales)" << std::endl;

34

35         return 0;  // indicate success

36     } else {  // transactions weren't for the same ISBN

37         std::cerr << "Data must refer to the same ISBN"

38                   << std::endl;

39         return -1; // indicate failure

40     }

41 }