双向链表（c++封装）

来源：互联网发布：java方法交换两个变量编辑：程序博客网时间：2024/05/21 08:48

 双向链表是链表的一种，它的每个数据结点中都有两个指针，分别指向直接后继和直接前驱。所以，从双向链表中的任意一个结点开始，都可以很方便地访问它的前驱结点和后继结点。结构图如下所示：其中_pPre是双向链表的前驱结点，_pNext是它的后继结点，_data是数据域

这里写图片描述

代码实现：

#define _CRT_SECURE_NO_WARNINGS 1#include<iostream>#include<assert.h>using namespace std;typedef int DataType;class Node{public:    Node(const DataType& data)         : _pNext(NULL)         , _pPre(NULL)         , _data(data)     {}     Node* _pNext;     Node* _pPre;     DataType _data; };class List { public:       friend ostream& operator<<(ostream& _cout, const List& list)//输出运算符的重载      {          Node* pCur = list._pHead;          if (pCur == NULL)//空链表              _cout << "NULL";          else          {              while (pCur->_pNext)            {                  _cout << pCur->_data << "->";                  pCur = pCur->_pNext;              }              _cout << pCur->_data << "->";              _cout << "NULL";          }          return _cout;      }      List()         : _pHead(NULL)     {}     List(DataType* array, size_t size)     {         for(size_t i = 0; i < size; ++i)         {            PushBack(array[i]);        }     }     List& operator=(const List& list)//赋值运算符的重载      {          Node* pCur = list._pHead;          if (this != &list)          {              while (pCur->_pNext)              {                  PushBack(pCur->_data);                  pCur = pCur->_pNext;              }              PushBack(pCur->_data);          }          return *this;      }  void PushBack(const DataType data);//尾插void PopBack();//尾删void PushFront(const DataType data); //头插void PopFront();。。头删Node* Find(const DataType data);//寻找指定元素Node* Erase(Node* pos); //任意位置删除Node* Insert(Node* pos, const DataType& data); //任意位置插入size_t Size()//求节点个数{    size_t i=0;    Node* pCur=_pHead;    if(_pHead==NULL)    {        return 0;    }    else    {        while(pCur->_pNext)        {            ++i;            pCur=pCur->_pNext;        }        return i+1;    }}void Clear(){    Node* pCur=_pHead;    if(_pHead==NULL)    {        return;    }    else    {        while(pCur->_pNext==NULL)        {            pCur->_pPre->_pNext=NULL;            delete pCur;        }        _pHead=NULL;    }}~List()    {        Node* _pCur=_pHead;        if(_pHead==NULL&&_pHead->_pNext==NULL)        {            return;        }        while(_pHead&&_pHead->_pNext)        {            _pCur=_pHead;            _pHead=_pHead->_pNext;            delete _pCur;        }        delete _pHead;    }private: Node* _pHead; };void List::PushBack(const DataType data) {     Node* pTail = _pHead;     Node* pNewNode = new Node(data);     if(_pHead==NULL)    {        _pHead=pNewNode;        pNewNode->_pPre=pTail;    }    else    {        while(pTail->_pNext)        {            pTail = pTail->_pNext;         }        pTail->_pNext = pNewNode;         pNewNode->_pPre = pTail;     }     pNewNode->_data=data;    pNewNode->_pNext=NULL;} void List::PopBack(){    Node* pCur=_pHead;    if(pCur==NULL)    {        return;    }    else    {        while(pCur->_pNext)        {            pCur=pCur->_pNext;        }           pCur->_pPre->_pNext=NULL;           delete pCur;    }}void List::PushFront(const DataType data){    Node* NewNode=new Node(data);    if(_pHead==NULL)    {        NewNode->_data=data;        NewNode->_pNext=_pHead;        NewNode->_pPre=NULL;        _pHead=NewNode;    }    _pHead->_pPre=NewNode;}void List::PopFront(){    Node* pCur=_pHead;    if(pCur==NULL)    {        return;    }    else        _pHead=_pHead->_pNext;        _pHead->_pPre=NULL;        delete pCur;}Node* List::Find(const DataType data){    Node* pCur=_pHead;    if(pCur==NULL)    {        return NULL;    }    else if((pCur->_pNext==NULL)&&(pCur->_data==data))    {        return pCur;    }    else    {        while(pCur->_pNext)        {            if(pCur->_data==data)                return pCur;            pCur=pCur->_pNext;        }    }    return NULL;}Node* List::Insert(Node* pos, const DataType& data)//任意位置删除{    Node* NewNode=new Node(data);    assert(pos);    if(pos==_pHead)    {        PushFront(data);    }    else if(pos->_pNext==NULL)    {        PushBack(data);    }    else    {        NewNode->_pNext=pos;        pos->_pPre->_pNext=NewNode;        NewNode->_pPre=pos->_pPre;        pos->_pPre=NewNode;        NewNode->_data=data;    }    return _pHead;}Node* List::Erase(Node* pos){    if(pos==NULL)    {        return _pHead;    }    if(pos==_pHead)    {        PopFront();    }    else    {        pos->_pPre->_pNext=pos->_pNext;        pos->_pNext->_pPre=pos->_pPre;        delete pos;    }    return _pHead;}DataType array[]={1,2,3};List list(array,sizeof(array)/sizeof(array[0]));void Test1()//PushBack PopBack {    list.PushBack(4);    cout<<list<<endl;    list.PopBack();    cout<<list<<endl;}void Test2()//PushFront PopFront{    list.PushFront(0);    cout<<list<<endl;    list.PopFront();    cout<<list<<endl;}void Test4()//Size Clear {    cout<<list<<endl;    size_t size=list.Size();    cout<<"Size="<<size<<endl;    list.Clear();    cout<<list<<endl;}void Test5()//Insert Find{    Node* pos=list.Find(2);    list.Insert(pos,5);    cout<<list<<endl;}void Test6()//Erase{    Node* pos=list.Find(2);    list.Erase(pos);    cout<<list<<endl;}void Test7()//赋值运算符的重载{    List list2;    list2=list;    cout<<list2<<endl;}int main(){    //Test1();    //Test2();    //Test3();    //Test4();    //Test5();    //Test6();    Test7();    system("pause");    return 0;}

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