#pragma once#include <iostream>
using namespace std;
#include <assert.h>namespace bite
{// List的節(jié)點(diǎn)類template<class T>struct ListNode{ListNode(const T& val = T()): _prev(nullptr), _next(nullptr), _val(val){}ListNode<T>* _prev;ListNode<T>* _next;T _val;};/*List 的迭代器迭代器有兩種實(shí)現(xiàn)方式，具體應(yīng)根據(jù)容器底層數(shù)據(jù)結(jié)構(gòu)實(shí)現(xiàn)：1. 原生態(tài)指針，比如：vector2. 將原生態(tài)指針進(jìn)行封裝，因迭代器使用形式與指針完全相同，因此在自定義的類中必須實(shí)現(xiàn)以下方法：1. 指針可以解引用，迭代器的類中必須重載operator*()2. 指針可以通過->訪問其所指空間成員，迭代器類中必須重載oprator->()3. 指針可以++向后移動(dòng)，迭代器類中必須重載operator++()與operator++(int)至于operator--()/operator--(int)釋放需要重載，根據(jù)具體的結(jié)構(gòu)來抉擇，雙向鏈表可以向前             移動(dòng)，所以需要重載，如果是forward_list就不需要重載--4. 迭代器需要進(jìn)行是否相等的比較，因此還需要重載operator==()與operator!=()*/template<class T, class Ref, class Ptr>class ListIterator{typedef ListNode<T> Node;typedef ListIterator<T, Ref, Ptr> Self;// Ref 和 Ptr 類型需要重定義下，實(shí)現(xiàn)反向迭代器時(shí)需要用到public:typedef Ref Ref;typedef Ptr Ptr;public://// 構(gòu)造ListIterator(Node* node = nullptr): _node(node){}//// 具有指針類似行為Ref operator*() { return _node->_val;}Ptr operator->() { return &(operator*()); }//// 迭代器支持移動(dòng)Self& operator++(){_node = _node->_next;return *this;}Self operator++(int){Self temp(*this);_node = _node->_next;return temp;}Self& operator--(){_node = _node->_prev;return *this;}Self operator--(int){Self temp(*this);_node = _node->_prev;return temp;}//// 迭代器支持比較bool operator!=(const Self& l)const{ return _node != l._node;}bool operator==(const Self& l)const{ return _node != l._node;}Node* _node;};template<class Iterator>class ReverseListIterator{// 注意：此處typename的作用是明確告訴編譯器，Ref是Iterator類中的一個(gè)類型，而不是靜態(tài)成員變量// 否則編譯器編譯時(shí)就不知道Ref是Iterator中的類型還是靜態(tài)成員變量// 因?yàn)殪o態(tài)成員變量也是按照 類名::靜態(tài)成員變量名 的方式訪問的public:typedef typename Iterator::Ref Ref;typedef typename Iterator::Ptr Ptr;typedef ReverseListIterator<Iterator> Self;public://// 構(gòu)造ReverseListIterator(Iterator it): _it(it){}//// 具有指針類似行為Ref operator*(){Iterator temp(_it);--temp;return *temp;}Ptr operator->(){return &(operator*());}//// 迭代器支持移動(dòng)Self& operator++(){--_it;return *this;}Self operator++(int){Self temp(*this);--_it;return temp;}Self& operator--(){++_it;return *this;}Self operator--(int){Self temp(*this);++_it;return temp;}//// 迭代器支持比較bool operator!=(const Self& l)const{return _it != l._it;}bool operator==(const Self& l)const{return _it != l._it;}Iterator _it;};template<class T>class list{typedef ListNode<T> Node;public:// 正向迭代器typedef ListIterator<T, T&, T*> iterator;typedef ListIterator<T, const T&, const T&> const_iterator;// 反向迭代器typedef ReverseListIterator<iterator> reverse_iterator;typedef ReverseListIterator<const_iterator> const_reverse_iterator;public:///// List的構(gòu)造list(){CreateHead();}list(int n, const T& value = T()){CreateHead();for (int i = 0; i < n; ++i)push_back(value);}template <class Iterator>list(Iterator first, Iterator last){CreateHead();while (first != last){push_back(*first);++first;}}list(const list<T>& l){CreateHead();// 用l中的元素構(gòu)造臨時(shí)的temp,然后與當(dāng)前對(duì)象交換list<T> temp(l.begin(), l.end());this->swap(temp);}list<T>& operator=(list<T> l){this->swap(l);return *this;}~list(){clear();delete _head;_head = nullptr;}///// List的迭代器iterator begin() { return iterator(_head->_next); }iterator end() { return iterator(_head); }const_iterator begin()const { return const_iterator(_head->_next); }const_iterator end()const{ return const_iterator(_head); }reverse_iterator rbegin(){return reverse_iterator(end());}reverse_iterator rend(){return reverse_iterator(begin());}const_reverse_iterator rbegin()const{return const_reverse_iterator(end());}const_reverse_iterator rend()const{return const_reverse_iterator(begin());}///// List的容量相關(guān)size_t size()const{Node* cur = _head->_next;size_t count = 0;while (cur != _head){count++;cur = cur->_next;}return count;}bool empty()const{return _head->_next == _head;}void resize(size_t newsize, const T& data = T()){size_t oldsize = size();if (newsize <= oldsize){// 有效元素個(gè)數(shù)減少到newsizewhile (newsize < oldsize){pop_back();oldsize--;}}else{while (oldsize < newsize){push_back(data);oldsize++;}}}// List的元素訪問操作// 注意：List不支持operator[]T& front(){return _head->_next->_val;}const T& front()const{return _head->_next->_val;}T& back(){return _head->_prev->_val;}const T& back()const{return _head->_prev->_val;}// List的插入和刪除void push_back(const T& val) { insert(end(), val); }void pop_back() { erase(--end()); }void push_front(const T& val) { insert(begin(), val); }void pop_front() { erase(begin()); }// 在pos位置前插入值為val的節(jié)點(diǎn)iterator insert(iterator pos, const T& val){Node* pNewNode = new Node(val);Node* pCur = pos._node;// 先將新節(jié)點(diǎn)插入pNewNode->_prev = pCur->_prev;pNewNode->_next = pCur;pNewNode->_prev->_next = pNewNode;pCur->_prev = pNewNode;return iterator(pNewNode);}// 刪除pos位置的節(jié)點(diǎn)，返回該節(jié)點(diǎn)的下一個(gè)位置iterator erase(iterator pos){// 找到待刪除的節(jié)點(diǎn)Node* pDel = pos._node;Node* pRet = pDel->_next;// 將該節(jié)點(diǎn)從鏈表中拆下來并刪除pDel->_prev->_next = pDel->_next;pDel->_next->_prev = pDel->_prev;delete pDel;return iterator(pRet);}void clear(){Node* cur = _head->_next;// 采用頭刪除刪除while (cur != _head){_head->_next = cur->_next;delete cur;cur = _head->_next;}_head->_next = _head->_prev = _head;}void swap(bite::list<T>& l){std::swap(_head, l._head);}private:void CreateHead(){_head = new Node;_head->_prev = _head;_head->_next = _head;}private:Node* _head;};
}///
// 對(duì)模擬實(shí)現(xiàn)的list進(jìn)行測試
// 正向打印鏈表
template<class T>
void PrintList(const bite::list<T>& l)
{auto it = l.begin();while (it != l.end()){cout << *it << " ";++it;}cout << endl;
}// 測試List的構(gòu)造
void TestBiteList1()
{bite::list<int> l1;bite::list<int> l2(10, 5);PrintList(l2);int array[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 };bite::list<int> l3(array, array + sizeof(array) / sizeof(array[0]));PrintList(l3);bite::list<int> l4(l3);PrintList(l4);l1 = l4;PrintList(l1);
}// PushBack()/PopBack()/PushFront()/PopFront()
void TestBiteList2()
{// 測試PushBack與PopBackbite::list<int> l;l.push_back(1);l.push_back(2);l.push_back(3);PrintList(l);l.pop_back();l.pop_back();PrintList(l);l.pop_back();cout << l.size() << endl;// 測試PushFront與PopFrontl.push_front(1);l.push_front(2);l.push_front(3);PrintList(l);l.pop_front();l.pop_front();PrintList(l);l.pop_front();cout << l.size() << endl;
}// 測試insert和erase
void TestBiteList3()
{int array[] = { 1, 2, 3, 4, 5 };bite::list<int> l(array, array + sizeof(array) / sizeof(array[0]));auto pos = l.begin();l.insert(l.begin(), 0);PrintList(l);++pos;l.insert(pos, 2);PrintList(l);l.erase(l.begin());l.erase(pos);PrintList(l);// pos指向的節(jié)點(diǎn)已經(jīng)被刪除，pos迭代器失效cout << *pos << endl;auto it = l.begin();while (it != l.end()){it = l.erase(it);}cout << l.size() << endl;
}// 測試反向迭代器
void TestBiteList4()
{int array[] = { 1, 2, 3, 4, 5 };bite::list<int> l(array, array + sizeof(array) / sizeof(array[0]));auto rit = l.rbegin();while (rit != l.rend()){cout << *rit << " ";++rit;}cout << endl;const bite::list<int> cl(l);auto crit = l.rbegin();while (crit != l.rend()){cout << *crit << " ";++crit;}cout << endl;
}

2.2 list的反向迭代器

template<class Iterator>
class ReverseListIterator
{// 注意：此處typename的作用是明確告訴編譯器，Ref是Iterator類中的類型，而不是靜態(tài)成員變量// 否則編譯器編譯時(shí)就不知道Ref是Iterator中的類型還是靜態(tài)成員變量// 因?yàn)殪o態(tài)成員變量也是按照 類名::靜態(tài)成員變量名 的方式訪問的
public:typedef typename Iterator::Ref Ref;typedef typename Iterator::Ptr Ptr;typedef ReverseListIterator<Iterator> Self;
public://// 構(gòu)造ReverseListIterator(Iterator it): _it(it){}//// 具有指針類似行為Ref operator*(){Iterator temp(_it);--temp;return *temp;}Ptr operator->(){ return &(operator*());}//// 迭代器支持移動(dòng)Self& operator++(){
--_it;return *this;}Self operator++(int){Self temp(*this);--_it;return temp;}Self& operator--(){++_it;return *this;}Self operator--(int){Self temp(*this);++_it;return temp;}//// 迭代器支持比較bool operator!=(const Self& l)const{ return _it != l._it;}bool operator==(const Self& l)const{ return _it != l._it;}Iterator _it;
};