队列——用C++模板实现

enqueue.h

//用"链表"实现队列//入队和出队的时间复杂度为O(1)//复制、清空和遍历队列的时间复杂度为O(n)template <class DT>struct Node{DT info;Node<DT> *next;};template <class DT>class Queue{public:Queue();Queue(const Queue<DT> &apqueue);~Queue();Queue<DT>& operator=(const Queue<DT> &apqueue);void enqueue(const DT &element);bool dequeue(DT &deqEle);bool peek(DT &frontEle); //得到对头的数据bool isEmpty() const;void makeEmpty();private:Node<DT> *front; //指向headerNode<DT> *back; //指向对尾结点Node<DT> header; //设置一个空的头结点inline void deepCopy(const Queue<DT> &apqueue); //"深复制"}; 

enqueue.cpp

#include "enqueue.h"template<class DT>Queue<DT>::Queue(){front = back = &header;}template<class DT>Queue<DT>::Queue(const Queue<DT> &apqueue){deepCopy(apqueue);}template<class DT>Queue<DT>::~Queue(){makeEmpty();}template<class DT>void Queue<DT>::enqueue(const DT &element){Node<DT> *ptr = new Node<DT>;ptr->info = element;back->next = ptr;back = ptr;}template<class DT>bool Queue<DT>::dequeue(DT &deqEle){if(back == &header)return false;Node<DT> *ptr;ptr = front->next;deqEle = ptr->info;front->next = ptr->next;if(back == ptr)back = front;delete ptr;return true;}template<class DT>bool Queue<DT>::peek(DT &frontEle){if(back == &header)return false;frontEle = front->next->info;return true;}template<class DT>bool Queue<DT>::isEmpty() const{return front == back;}template<class DT>void Queue<DT>::makeEmpty(){DT temp;while( dequeue(temp) );}template<class DT>void Queue<DT>::deepCopy(const Queue<DT> &apqueue){Node<DT> *oriPtr = apqueue.front;//Node<DT> *ptr = new Node<DT>;//front = ptr = oriPtr; //这样赋值就把apqueue和this绑在一起拉...Node<DT> *ptr = front = &header;while(oriPtr != apqueue.back) //循环体中操作oriPtr->next的内容，这样就可以把apqueue.back拷贝进去！{ptr->next = new Node<DT>;ptr = ptr->next;oriPtr = oriPtr->next;ptr->info = oriPtr->info;}back = ptr;} 

测试用例：

#include<iostream>#include<string>#include "enqueue.cpp"using namespace std;void main(){string str[9] = {"the","quick","fox","jumps","over","the","slow","red","turtle"};Queue<string> obj;string s;for(size_t ix=0;ix<9;++ix){obj.enqueue(str[ix]);}Queue<string> obj1(obj); //测试复制构造函数obj1.peek(s);cout<<s<<endl;for(size_t ix=0;ix<9;++ix) //利用dequeue进行毁灭式遍历队列{ obj1.dequeue(s);cout<<s<<",";}if(obj1.isEmpty())cout<<endl<<"obj1 is empty!"<<endl; Queue<string> obj2 = obj; //测试重载“=”操作符obj2.peek(s);cout<<s<<endl;for(size_t ix=0;ix<9;++ix){ obj.dequeue(s);cout<<s<<",";}}