基于List实现适配器queue(链式队列)

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这里写图片描述

队列遵循先进先出，后进后出的原则，它有两个出口，从最底端加入元素、取得最顶端的元素。实现队列我们通常建立在链表的基础上。下来我们利用之前实现过的容器List中的一部分接口来实现queue
（在这里分别用了模板参数和模板的模板参数两种方式来实现来实现）

queue.h

#pragma once#include "List.h"//模板参数template<class T,class Container=List<T>>class Queue1{public:    Queue1()    {}    void Push(const T& data)    {        s.PushBack(data);    }    void Pop()    {        s.PopFront();    }    bool Empty()    {        return s.Empty();    }    size_t Size()    {        return s.Size();    }    T& Front()    {        return s.Front();    }    const T& Front()const    {        return s.Front();    }    T& Back()    {        return s.Back();    }    const T& Back()const    {        return s.Back();    }private:    List<T> s;};//模板的模板参数template<class T, template<class> class Container = List>class Queue2{public:    Queue2()    {}    void Push(const T& data)    {        s.PushBack(data);    }    void Pop()    {        s.PopFront();    }    bool Empty()    {        return s.Empty();    }    size_t Size()    {        return s.Size();    }    T& Front()    {        return s.Front();    }    const T& Front()const    {        return s.Front();    }    T& Back()    {        return s.Back();    }    const T& Back()const    {        return s.Back();    }private:    List<T> s;};

List.h

#define _CRT_SECURE_NO_WARNINGS 1#pragma once#include <stdlib.h>#include <iostream>using namespace std;template<class T>struct ListNode{    ListNode(const T& data = T())    : _pPre(0)    , _pNext(0)    , _data(data)    {}    ListNode<T>* _pPre;    ListNode<T>* _pNext;    T _data;};template<class T,class Ref,class Ptr>class ListIterator{    typedef ListIterator<T, Ref, Ptr> Self;public:    ListIterator()        :_pCur(0)    {}    ListIterator(ListNode<T>* pCur)        : _pCur(pCur)    {}    ListIterator(const Self& s)        : _pCur(s._pCur)    {}    Ref operator*()    {        return _pCur->_data;    }    Ptr operator->()    {        return &(operator*());        //return &(_pCur->_data);     }    Self& operator++()    {        _pCur = _pCur->_pNext;        return*this;    }    Self operator++(int)    {        Self temp(*this);        _pCur = _pCur->_pNext;        return temp;    }    Self& operator--()    {        _pCur = _pCur->_pPre;        return*this;    }    Self operator--(int)    {        Self temp(*this);        _pCur = _pCur->_pPre;        return temp;    }    bool operator!=(const Self& s)    {        return _pCur != s._pCur;    }    bool operator==(const Self& s)    {        return _pCur == s._pCur;    }    ListNode<T>* _pCur;};template <class T>class List{public:    typedef ListIterator<T, T&, T*> Iterator;    typedef ListNode<T> Node;public:    List()        : _pHead(new Node)    {        _pHead->_pNext = _pHead;//带头节点的循环链表        _pHead->_pPre = _pHead;    }    // 1 2 3 4 5     List(const T* array, size_t size)        :_pHead(new Node)    {        _pHead->_pNext = _pHead;        _pHead->_pPre = _pHead;        for (size_t i = 0; i < size; i++)        {            PushBack(array[i]);        }    }    List(const List<T>& l)        :_pHead(new Node)    {        _pHead->_pNext = _pHead;        _pHead->_pPre = _pHead;        Node* cur = l._pHead->_pNext;        for (size_t i = 0; i < l.Size();i++)        {            PushBack(cur->_data);            cur = cur->_pNext;        }    }    List<T>& operator=(const List<T>& l)    {        if (this != &l)        {            Node* pRet = l._pHead->_pNext;            for (size_t i = 0; i < l.Size(); i++)            {                PushBack(pRet->_data);                pRet = pRet->_pNext;            }        }        return *this;    }    ~List()    {        Clear();        delete _pHead;        _pHead = NULL;    }        /////////////////////////////////////////////////////     Iterator Begin()    {        return Iterator(_pHead->_pNext);    }    Iterator End()    {        return Iterator(_pHead);    }    /////////////////////Modify//////////////////////////     void PushBack(const T& data)    {        Node* _pNewNode = new Node(data);        if (Empty())//链表为空        {            _pHead->_pNext = _pNewNode;            _pHead->_pPre = _pNewNode;            _pNewNode->_pNext = _pHead;            _pNewNode->_pPre = _pHead;        }        else        {            Node* pTail = _pHead->_pPre;            pTail->_pNext = _pNewNode;            _pNewNode->_pNext = _pHead;            _pNewNode->_pPre = pTail;            _pHead->_pPre = _pNewNode;        }    }    void PopBack()    {        if (Empty())//链表为空        {            return;        }        else        {            Node* del = _pHead->_pPre;//要删除的节点            Node* tail = del->_pPre;//新的尾节点            delete del;            tail->_pNext = _pHead;            _pHead->_pPre = tail;        }    }    void PushFront(const T& data)    {        Node* _pNewNode = new Node(data);        _pHead->_pNext->_pPre = _pNewNode;        _pNewNode->_pNext = _pHead->_pNext;        _pNewNode->_pPre = _pHead;        _pHead->_pNext = _pNewNode;    }    void PopFront()    {        if (Empty())        {            return;        }        else        {            Node* pDel = _pHead->_pNext;            _pHead->_pNext = pDel->_pNext;            pDel->_pNext->_pPre = _pHead;            delete pDel;        }    }    Iterator Insert(Iterator pos, const T& data)    {        Node* _pNewNode = new Node(data);        pos._pCur->_pPre->_pNext = _pNewNode;        _pNewNode->_pNext = pos._pCur;        _pNewNode->_pPre = pos._pCur->_pPre;        pos._pCur->_pPre = _pNewNode;        return Iterator(_pNewNode);    }    Iterator Erase(Iterator pos)    {        Node* pCur = pos._pCur->_pNext;        pos._pCur->_pNext->_pPre = pos._pCur->_pPre;        pos._pCur->_pPre->_pNext = pos._pCur->_pNext;        delete pos._pCur;        return Iterator(pCur);    }    Iterator Find(const T& d)        //通过迭代器来查找    {        Iterator it = Begin();        while (it != End())        {            if ((*it) == d)                return it;            it++;        }        return End();    }    bool Empty()const    {        return _pHead->_pNext == _pHead;    }    size_t Size()const    {        Node* pCur = _pHead->_pNext;        size_t count = 0;        while (pCur != _pHead)        {            ++count;            pCur = pCur->_pNext;        }        return count;    }    T& Front()    {        return _pHead->_pNext->_data;    }    const T& Front()const    {        return _pHead->_pNext->_data;    }    T& Back()    {        return _pHead->_pPre->_data;    }    const T& Back()const    {        return _pHead->_pPre->_data;    }    void Clear()    {        Iterator it = Begin();        while (it != End())        {            it = Erase(it);        }        _pHead->_pNext = _pHead;        _pHead->_pPre = _pHead;    }private:    ListNode<T>* _pHead;};void PrintList( List<int>& l){    List<int>::Iterator It = l.Begin();    while (It != l.End())    {        cout << *It << " ";        ++It;    }    cout << endl;}

测试代码

#define _CRT_SECURE_NO_WARNINGS 1#include "queue.h"void FunTest1(){    Queue1<int, List<int>> q1;    for (int i = 0; i <= 5; i++)    {        q1.Push(i);    }    while (!q1.Empty())    {        cout << q1.Front() << " ";        q1.Pop();    }    cout << endl;}void FunTest2(){    Queue2<int, List> q2;    for (int i = 0; i <= 5; i++)    {        q2.Push(i);    }    while (!q2.Empty())    {        cout << q2.Front() << " ";        q2.Pop();    }    cout << endl;}int main(){    FunTest1();    FunTest2();    system("pause");    return 0;}

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