www.gusucode.com > C++ Primer 书籍源代码源码程序 > C++ Primer 书籍源代码源码程序/code/15/Basket.cpp
//Download by http://www.NewXing.com /* * 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 "Basket.h" #include <algorithm> using std::multiset; using std::map; using std::pair; using std::size_t; using std::string; using std::ostream; using std::endl; using std::min; using std::cout; // debugging routine to check contents in a Basket void Basket::display(ostream &os) const { os << "Basket size: " << items.size() << endl; // print each distinct isbn in the Basket along with // count of how many copies are ordered and what their price will be // upper_bound returns an iterator to the next item in the set for (const_iter next_item = items.begin(); next_item != items.end(); next_item = items.upper_bound(*next_item)) { // we know there's at least one element with this key in the Basket os << (*next_item)->book() << " occurs " << items.count(*next_item) << " times" << " for a price of " << (*next_item)->net_price(items.count(*next_item)) << endl; } } void print_total(ostream &, const Item_base&, size_t); // calculate and print price for given number of copies, applying any discounts void print_total(ostream &os, const Item_base &item, size_t n) { os << "ISBN: " << item.book() // calls Item_base::book << "\tnumber sold: " << n << "\ttotal price: " // virtual call: which version of net_price to call is resolved at run time << item.net_price(n) << endl; } double Basket::total() const { double sum = 0.0; // holds the running total for (const_iter iter = items.begin(); iter != items.end(); iter = items.upper_bound(*iter)) { // we know there's at least one element with this key in the Basket print_total(cout, *(iter->p), items.count(*iter)); // virtual call to net_price applies appropriate discounts, if any sum += (*iter)->net_price(items.count(*iter)); } return sum; } // use-counted assignment operator; use is a pointer to a shared use count Sales_item& Sales_item::operator=(const Sales_item &rhs) { ++*rhs.use; decr_use(); p = rhs.p; use = rhs.use; return *this; } // if specified number of items are purchased, use discounted price double Bulk_item::net_price(size_t cnt) const { if (cnt >= min_qty) return cnt * (1 - discount) * price; else return cnt * price; } // use discounted price for up to a specified number of items // additional items priced at normal, undiscounted price double Lim_item::net_price(size_t cnt) const { size_t discounted = min(cnt, max_qty); size_t undiscounted = cnt - discounted; return discounted * (1 - discount) * price + undiscounted * price; }