avg_price.cpp

C++primer里常用的小程序

/*
 * This file contains code from "C++ Primer, Fourth Edition", by Stanley B.
 * Lippman, Jose Lajoie, and Barbara E. Moo, and is covered under the
 * copyright and warranty notices given in that book:
 * 
 * "Copyright (c) 2005 by Objectwrite, Inc., Jose Lajoie, and Barbara E. Moo."
 * 
 * 
 * "The authors and publisher have taken care in the preparation of this book,
 * but make no expressed or implied warranty of any kind and assume no
 * responsibility for errors or omissions. No liability is assumed for
 * incidental or consequential damages in connection with or arising out of the
 * use of the information or programs contained herein."
 * 
 * Permission is granted for this code to be used for educational purposes in
 * association with the book, given proper citation if and when posted or
 * reproduced.Any commercial use of this code requires the explicit written
 * permission of the publisher, Addison-Wesley Professional, a division of
 * Pearson Education, Inc. Send your request for permission, stating clearly
 * what code you would like to use, and in what specific way, to the following
 * address: 
 * 
 * 	Pearson Education, Inc.
 * 	Rights and Contracts Department
 * 	75 Arlington Street, Suite 300
 * 	Boston, MA 02216
 * 	Fax: [phone]
*/ 

#include <iostream>
#include "Sales_item.h"

int main() 
{
    // declare variables to hold running sum and data for the next record 
    Sales_item total, trans;

    // is there data to process?
    if (std::cin >> total) {
        // if so, read the transaction records 
        while (std::cin >> trans)
            if (total.same_isbn(trans)) 
                // match: update the running total 
                total = total + trans;
            else {   
                // no match: print & assign to total
                std::cout << total << std::endl;
                total = trans;
            }
        // remember to print last record
        std::cout << total << std::endl; 
    } else {
        // no input!, warn the user
        std::cout << "No data?!" << std::endl;
        return -1;  // indicate failure
    }

    return 0;
}