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//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 "MS_Queue.h" #include <stdexcept> using std::out_of_range; #include <iostream> using std::ostream; //web-comment-begin template <class Type> void Queue<Type>::copy_elems(const Queue &orig) { // copy elements from orig into this Queue QueueItem *pt = orig.head; while (pt) { // last element has next pointer == 0 push(pt->item); // copy the element pt = pt->next; // get the next one from orig } } template <class Type> Queue<Type>& Queue<Type>::operator=(const Queue &rhs) { if (this != &rhs) { // destroy elements on this Queue destroy(); copy_elems(rhs); // copy from rhs into left-hand Queue } return *this; } template <class Type> void Queue<Type>::destroy() { while (!empty()) pop(); } template <class Type> void Queue<Type>::push(const Type &val) { // allocate a new QueueItem object QueueItem *pt = new QueueItem(val); // put item onto existing queue if (empty()) head = tail = pt; // queue has only one element else { tail->next = pt; // add new element to end of queue tail = pt; } } //begin{pop-defn} template <class Type> void Queue<Type>::pop() { // pop is unchecked: popping off an empty Queue is undefined QueueItem* p = head; // keep pointer to head so can delete it head = head->next; // head now points to next element delete p; // delete old head element } //end{pop-defn} template <class Type> ostream& operator<<(ostream &os, const Queue<Type> &q) { os << "< "; typename Queue<Type>::QueueItem *p; for (p = q.head; p; p = p->next) os << p->item << " "; os <<">"; return os; }