C++ Primer 第五版 1.6 书店程序 笔记

 1#include <iostream>
 2#include "Sales_item.h"
 3int main()
 4{
 5    Sales_item total; // variable to hold data for the next transaction
 6    // read the first transaction and ensure that there are data to process
 7    if (std::cin >> total)
 8    {
 9        Sales_item trans; // variable to hold the running sum
10        // read and process the remaining transactions
11        while (std::cin >> trans)
12        {
13            // if we’re still processing the same book
14            if (total.isbn() == trans.isbn())
15                total += trans; // update the running total
16            else
17            {
18                // print results for the previous book
19                std::cout << total << std::endl;
20                total = trans; // total now refers to the next book
21            }
22        }
23        std::cout << total << std::endl; // print the last transaction
24    }
25    else
26    {
27        // no input! warn the user
28        std::cerr << "No data?!" << std::endl;
29        return -1; // indicate failure
30    }
31    return 0;
32}
33
34/* input:
350-201-70353-X 4 24.99
360-201-82470-1 4 45.39
370-201-88954-4 2 15.00
380-201-88954-4 5 12.00
390-201-88954-4 7 12.00
400-201-88954-4 2 12.00
410-399-82477-1 2 45.39
420-399-82477-1 3 45.39
430-201-78345-X 3 20.00
440-201-78345-X 2 25.00
45*/