Sales_item.h
资源名称:CppPrimer.rar [点击查看]
上传用户:qdkongtiao
上传日期:2022-06-29
资源大小:356k
文件大小:3k
源码类别:
书籍源码
开发平台:
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 <iostream>
- #include <string>
- class Sales_item {
- friend bool compare(const Sales_item&, const Sales_item&);
- friend bool operator==(const Sales_item&, const Sales_item&);
- public:
- Sales_item(const std::string &book):
- isbn(book), units_sold(0), revenue(0.0) { }
- Sales_item(std::istream &is) { is >> *this; }
- friend std::istream& operator>>(std::istream&, Sales_item&);
- friend std::ostream& operator<<(std::ostream&, const Sales_item&);
- public:
- // operations on Sales_item objects
- Sales_item& operator+=(const Sales_item&);
- double avg_price() const;
- bool same_isbn(const Sales_item &rhs) const
- { return isbn == rhs.isbn; }
- // default constructor needed to initialize members of built-in type
- Sales_item(): units_sold(0), revenue(0.0) { }
- std::string book() const { return isbn; }
- private:
- std::string isbn;
- unsigned units_sold;
- double revenue;
- };
- // nonmember binary operator: must declare a parameter for each operand
- Sales_item operator+(const Sales_item&, const Sales_item&);
- inline bool
- operator==(const Sales_item &lhs, const Sales_item &rhs)
- {
- // must be made a friend of Sales_item
- return lhs.units_sold == rhs.units_sold &&
- lhs.revenue == rhs.revenue &&
- lhs.same_isbn(rhs);
- }
- inline bool
- operator!=(const Sales_item &lhs, const Sales_item &rhs)
- {
- return !(lhs == rhs); // != defined in terms of operator==
- }
- inline bool
- compare(const Sales_item &lhs, const Sales_item &rhs)
- {
- return lhs.book() < rhs.book();
- }