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//Download by http://www.NewXing.com #include "MS_Queue.h" #include <stdexcept> using std::out_of_range; #include <iostream> using std::ostream; template <class Type> void Queue<Type>::copy_elems(const Queue &orig) { // copy elements from orig into this Queue // loop stops when pt == 0, which happens when we reach orig.tail for (QueueItem<Type> *pt = orig.head; pt; pt = pt->next) push(pt->item); // copy the element } 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<Type> *pt = new QueueItem<Type>(val); // put item onto existing queue if (empty()) head = tail = pt; // the queue now has only one element else { tail->next = pt; // add new element to end of the queue tail = pt; } } template <class Type> void Queue<Type>::pop() { // pop is unchecked: Popping off an empty Queue is undefined QueueItem<Type>* p = head; // keep pointer to head so we can delete it head = head->next; // head now points to next element delete p; // delete old head element } template <class Type> ostream& operator<<(ostream &os, const Queue<Type> &q) { os << "< "; QueueItem<Type> *p; for (p = q.head; p; p = p->next) os << p->item << " "; os <<">"; return os; }