模板实现双向链表

来源：互联网发布：excel多表格数据合计编辑：程序博客网时间：2024/05/21 05:41
c++模板实现双向链表：
#include <iostream>#include <assert.h>using namespace std;template<typename T>struct ListNode {    T _data;    ListNode<T>* _prev;    ListNode<T>* _next;    ListNode()        :_next(NULL)        , _prev(NULL)    {}};template<typename T>class List{    typedef ListNode<T> Node;public:    List()        :_head(NULL)        ,_tail(NULL)    {}    List<T>& operator=(List<T> list)    {        swap(_head, list._head);        swap(_tail, list._tail);        return *this;    }    List( const List<T>& s)//   ?????        :_tail(NULL)        , _head(NULL)    {        Node* cur = s._head;        while (cur)        {            PushBack(cur->_data);            cur = cur->_next;        }    }    void PushBack(const T& x)//1、空链表2、有多个元素    {        if (_tail == NULL)//空链表        {            _head = _tail = new Node;            _tail->_data = x;            _head->_next = NULL;            _head->_prev = NULL;        }        else//多个元素        {            Node* p = new Node;            p->_data = x;            _tail->_next = p;            p->_prev = _tail;            _tail = p;            _head->_prev = NULL;            _tail->_next = NULL;        }    }    void PopBack()//1、空链表2、一个元素3、多个元素    {        if (NULL == _head)        {            _head = new Node(x);        }        else if (_head == _tail)//一个结点        {            delete _tail;            _tail = _head = NULL;        }        else//多个结点        {            Node* tmp = _tail->_prev;            delete[] _tail;            _tail = tmp;            _tail ->_next= NULL;        }    }    void PushFront(const T&x)//头插(1、空2、不空)    {        Node* newnode = new Node(x);        if (_head == NULL)        {            newnode->_next = NULL;            newnode->_prev = NULL;            _head = _tail = newnode;        }        else        {            Node* tmp = _head;            newnode->_next = tmp;            tmp->_prev = newnode;            _head = newnode;            newnode->_prev = NULL;        }    }    void PopFront()    {        Node* tmp = _head->_next;        delete[] _head;        _head = tmp;    }    void Insert(Node* pos, T x)//pos前面插    {        assert(pos);        Node* newnode = new Node(x);        Node* tmp = pos->_prev;//保存pos位置前一个节点地址        if (tmp)//pos不是第一个节点        {            tmp->_next = newnode;//将新节点和前一个连接            newnode->_prev = tmp;        }        else//pos是第一个节点        {            _tail = newnode;            newnode->_prev = NULL;        }        newnode->_next = pos;        pos->_prev = newnode;    }    ~List()//析构函数    {           Node* tmp = _head;        Node* cur = NULL;        while (tmp)        {            cur = tmp->_next;            delete[] tmp;            tmp = cur;          }    }     Node* Find(const T &x)    {        Node* cur = _head;        while (cur)        {            if (cur->_data == x)            {                return cur;            }            cur = cur->_next;        }    }    void Erase(Node* pos)//1、空2、删头3、删尾4、删中间    {        assert(pos);        if (NULL == _head)//空        {            return;        }        else if (_head == _tail)//一个元素        {            assert(_head != pos);            delete[] _head;            _head = _tail = NULL;        }        else if (_head == pos)//pos为头        {            Node* cur = _head->_next;            delete[] _head;            _head = cur;            cur->_prev = NULL;        }        else if (_tail == pos)        {            Node* cur = _tail->_prev;            delete[] _tail;            _tail = cur;            cur->_next = NULL;        }        else         {            Node* prev = pos->_prev;            Node* next = pos->_next;            delete[] pos;            prev->_next = next;            next->_prev = prev;        }    }    void Print()    {        Node* cur = _head;        while (cur != NULL)        {            cout << cur->_data<< endl;            cur = cur->_next;        }    }private:    Node* _tail;    Node* _head;};int main(){    List<int> a;    a.PushBack(1);    a.PushBack(2);    a.PushBack(3);    a.PushBack(4);    a.PushBack(5);    /*a.Erase(a.Find(3));    a.Erase(a.Find(2));    a.Erase(a.Find(1));*/    List<int> b(a);    b.PushBack(4);    b.PushBack(5);    b = a;    b.Print();    system("pause");    return 0;}
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