模拟实现list(迭代器)

来源：互联网发布：centos 7 乱码编辑：程序博客网时间：2024/06/07 10:03

#pragma  once;#include <assert.h>#include<iostream>#include <assert.h>using namespace std;template<class T>struct __ListNode{     T  _data; __ListNode<T>* _next; __ListNode<T>* _prev;  __ListNode(const T& x)  :_data(x)  ,_next(NULL)  ,_prev(NULL)  {  }};template <class T,class Ref,class Ptr >struct __ListIterator{typedef  __ListNode<T>   Node;    typedef  __ListIterator<T,Ref,Ptr> Self;__ListIterator(Node* node)   :_node(node){}Ref  operator*(){    return _node->_data;}Ptr  operator->(){    return &(_node->_data)}Self& operator++(){   _node=_node->_next;   return *this;}Self& operator--(){_node=_node->_prev;return *this;}Self operator++(int){Self tmp=_node;_node=_node->_next;//return tmp;return Self(tmp)   }Self  operator--(int){   Self tmp=(*this);_node=_node->_prev;return tmp;}bool operator!=(const Self& s) const{ return this->_node!=s._node;}bool operator==(const Self& s) const{return this->_node==s._node;}Node* _node;};template<class T>struct List{    typedef  __ListNode<T> Node;public:typedef  __ListIterator<T,T&,T*> Iterator;typedef  __ListIterator<T,const T&,const T*> ConstIterator;Node* GetNode(const T& x){return new Node(x);}List(){       _head=GetNode(T());   _head->_next=_head;   _head->_prev=_head;}Iterator Begin(){  return Iterator(_head->_next);}Iterator End(){  return Iterator(_head);}ConstIterator Begin() const{return ConstIterator(_head->_next);}ConstIterator End() const{return ConstIterator(_head);} void PushBack(const T& x){  /*  Node* _tail=_head->_prev;Node* tmp=GetNode(x);_tail->_next=tmp;tmp->_prev=_tail;tmp->_next=_head;_head->_prev=tmp;*/Insert(End(),x);}  void PopBack()  { /* assert(_head->_prev );      Node* tail=_head->_prev;  Node* prev=tail->_prev;  Node* next=tail->_next;  prev->_next=next;  next->_prev=prev;  delete tail;*/  Erase(--End());  }  void PushFront(const T& x)  {    /*assert(_head)  Node* tmp=GetNode(x);      Node* next=_head->_next;  _head->_next=tmp;  tmp->_prev=_head;  tmp->_next=next;       next->_prev=tmp;*/  Insert(Begin(),x);  }  void PopFront()  {  /*assert(_head->_next);     Node* tmp=_head->_next; Node* next=tmp->_next;     _head->_next= next; next->_prev=_head; delete tmp;*/       Erase(Begin());  } Iterator Insert(Iterator pos, const T& x) {     assert(pos._node); Node* tmp=GetNode(x); Node* cur=pos._node; Node* prev=cur->_prev;    prev->_next=tmp; tmp->_prev=prev; tmp->_next=cur; cur->_prev=tmp; return  tmp; } Iterator  Erase(Iterator pos){assert(pos._node && pos._node!=NULL);Node* tmp=pos._node;Node* next=tmp->_next;Node* prev=tmp->_prev;  next->_prev=prev;prev->_next=next;delete tmp;return Iterator(next);} protected:Node* _head;};void PrintList(const List<int>& l){List<int>::ConstIterator It=l.Begin();while(It!=l.End()){    cout<<*It<<" ";   ++It;}cout<<endl;} void TestList2(){List<int> l2;l2.PushBack(1); l2.PushBack(2);l2.PushBack(3);l2.PushBack(4);   l2.PopBack();     l2.PopBack();  l2.PopBack();   l2.PopBack();    l2.PopBack(); PrintList(l2);}void TestList3(){List<int> l3;l3.PushFront(1);l3.PushFront(2);l3.PushFront(3);l3.PushFront(4);l3.PopFront();l3.PopFront();l3.PopFront();PrintList(l3); }

#include "List.h"int main(){//TestList1();     //TestList2();  TestList3();  return 0;}

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