Sales_item.cpp
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上传日期:2022-06-29
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书籍源码
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Visual C++
- /*
- * 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: (617) 848-7047
- */
- #include "bookexcept.h"
- #include "Sales_item.h"
- #include <iostream>
- using std::istream; using std::ostream;
- // assumes that both objects refer to the same isbn
- Sales_item&
- Sales_item::operator+=(const Sales_item& rhs)
- {
- units_sold += rhs.units_sold;
- revenue += rhs.revenue;
- return *this;
- }
- // throws exception if both objects do not refer to the same isbn
- Sales_item
- operator+(const Sales_item& lhs, const Sales_item& rhs)
- {
- if (!lhs.same_isbn(rhs))
- throw isbn_mismatch("isbn mismatch",
- lhs.book(), rhs.book());
- Sales_item ret(lhs); // copy lhs into a local object that we'll return
- ret += rhs; // add in the contents of rhs
- return ret; // return ret by value
- }
- istream&
- operator>>(istream& in, Sales_item& s)
- {
- double price;
- in >> s.isbn >> s.units_sold >> price;
- // check that the inputs succeeded
- if (in)
- s.revenue = s.units_sold * price;
- else
- s = Sales_item(); // input failed, reset object to default state
- return in;
- }
- ostream&
- operator<<(ostream& out, const Sales_item& s)
- {
- out << s.isbn << "t" << s.units_sold << "t"
- << s.revenue << "t" << s.avg_price();
- return out;
- }
- double Sales_item::avg_price() const
- {
- if (units_sold)
- return revenue/units_sold;
- else
- return 0;
- }