双向循环链表——STL迭代器

“test.cpp”

<strong><span style="font-size:18px;">#define _CRT_SECURE_NO_WARNINGS 1#include<iostream>using namespace std;template<class T>struct ListNode{ListNode<T>* _prev;ListNode<T>* _next;T _data;ListNode(const T& data):_prev(NULL),_next(NULL),_data(data){}};template<class T,class Ref,class Ptr>struct ListIterator{typedef ListNode<T> Node;typedef ListIterator<T,Ref,Ptr> Self;Node* _node;ListIterator(){}ListIterator(Node* node):_node(node){}bool operator==(const Self& s) const{return _node == s._node;}bool operator!=(const Self& s) const{return _node != s._node;}Self& operator++() {_node = _node->_next;return *this;}Self operator++(int) {Self tmp(_node);_node = _node->_next;return tmp;}Self& operator--(){_node = _node->_prev;return *this;}Self operator--(int){Self tmp(_node);_node = _node->_prev;return tmp;}Ref operator*(){return _node->_data;}Ptr operator->(){return &(*_node->_data);}};template<class T>class List{typedef ListNode<T> Node;public:typedef ListIterator<T,T&,T*> Iterator;public:Node* BuyNode(const T& data){Node* tmp = new Node(data);return tmp;}List(){_head = BuyNode(T());_head->_prev = _head;_head->_next = _head;}//void PushBack(const T& data)//{//Node* tail = _head->_prev;//Node* node = BuyNode(data);//node->_prev = tail;//node->_next = tail->_next;//tail->_next = node;//_head->_prev = node;//}void PushBack(const T& data){Insert(End(),data);}void PushFront(const T& data){Insert(Begin(),data);}//在指定位置前的一个位置插入void Insert(Iterator pos,const T& data){Node* cur = pos._node;Node* prev = cur->_prev;Node* tmp = BuyNode(data);tmp->_prev = prev;tmp->_next = cur;prev->_next = tmp;cur->_prev = tmp;}void PopBack(){//Erase(Iterator(_head->_prev));Erase(--End());}void PopFront(){//Erase(Iterator(_head->_next));Erase(Begin());}//指定位置删除void Erase(Iterator pos){Node* del = pos._node;Node* prev = del->_prev;Node* cur = del->_next;prev->_next = cur;cur->_prev = prev;delete del;del = NULL;}Iterator Begin(){return Iterator(_head->_next);}Iterator End(){return Iterator(_head);}private:Node* _head;};void test(){List<int> l;for(int i = 0;i < 5;i++){l.PushBack(i);}for (int i = 5;i < 10;i++){l.PushFront(i);}List<int>::Iterator it = l.Begin();while (it != l.End()){cout<<*it<<" ";it++;}cout<<endl;l.PopBack();l.PopBack();l.PopFront();l.PopFront();it = l.Begin();while (it != l.End()){cout<<*it<<" ";it++;}cout<<endl;}int main(){test();system("pause");return 0;}</span></strong>