目录

1. list的使用

1.1 list的构造

 1.2 list iterator的使用

1.3 list capacity

1.4 list element access

1.5 list modifiers

1.6 list的迭代器失效

2. list的模拟实现

3. list与vector的对比

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1. list的使用

1.1 list的构造

 1.2 list iterator的使用

1. begin与end为正向迭代器，对迭代器执行++操作，迭代器向后移动

2. rbegin(end)与rend(begin)为反向迭代器，对迭代器执行++操作，迭代器向前移动

1.3 list capacity

1.4 list element access

1.5 list modifiers

1.6 list的迭代器失效

        迭代器失效即迭代器所指向的节点的无效，即该节 点被删除了。因为list的底层结构为带头结点的双向循环链表，因此在list中进行插入时是不会导致list的迭代 器失效的，只有在删除时才会失效，并且失效的只是指向被删除节点的迭代器，其他迭代器不会受到影响。

2. list的模拟实现

#pragma once
#include<assert.h>namespace erdong
{template<class T>struct list_node{list_node<T>* _next;list_node<T>* _prev;T _val;list_node(const T& val = T()):_next(nullptr), _prev(nullptr), _val(val){}};// typedef __list_iterator<T, T&, T*> iterator;// typedef __list_iterator<T, const T&, const T*> const_iterator;template<class T, class Ref, class Ptr>struct __list_iterator{typedef list_node<T> Node;typedef __list_iterator<T, Ref, Ptr> self;Node* _node;__list_iterator(Node* node):_node(node){}Ref operator*(){return _node->_val;}Ptr operator->(){return &_node->_val;}self& operator++(){_node = _node->_next;return *this;}self operator++(int){self tmp(*this);_node = _node->_next;return tmp;}self& operator--(){_node = _node->_prev;return *this;}self operator--(int){self tmp(*this);_node = _node->_prev;return tmp;}bool operator!=(const self& it) const{return _node != it._node;}bool operator==(const self& it) const{return _node == it._node;}};/*template<class T>struct __list_const_iterator{typedef list_node<T> Node;Node* _node;__list_const_iterator(Node* node):_node(node){}const T& operator*(){return _node->_val;}__list_const_iterator<T>& operator++(){_node = _node->_next;return *this;}__list_const_iterator<T> operator++(int){__list_const_iterator<T> tmp(*this);_node = _node->_next;return tmp;}bool operator!=(const __list_const_iterator<T>& it){return _node != it._node;}bool operator==(const __list_const_iterator<T>& it){return _node == it._node;}};*/template<class T>class list{typedef list_node<T> Node;public:typedef __list_iterator<T, T&, T*> iterator;typedef __list_iterator<T, const T&, const T*> const_iterator;// 这么设计太冗余了，看看库里面如何设计的//typedef __list_const_iterator<T> const_iterator;// 这样设计const迭代器是不行的，因为const迭代器期望指向内容不能修改// 这样设计是迭代器本身不能修改// typedef const __list_iterator<T> const_iterator;// const T* ptr1;// T* const ptr2;// 如何设计const迭代器？iterator begin(){//return _head->_next;return iterator(_head->_next);}iterator end(){return _head;//return iterator(_head);}const_iterator begin() const{//return _head->_next;return const_iterator(_head->_next);}const_iterator end() const{return _head;//return const_iterator(_head);}void empty_init(){_head = new Node;_head->_prev = _head;_head->_next = _head;_size = 0;}list(){empty_init();}// lt2(lt1)list(const list<T>& lt)//list(const list& lt){empty_init();for (auto& e : lt){push_back(e);}}void swap(list<T>& lt){std::swap(_head, lt._head);std::swap(_size, lt._size);}list<T>& operator=(list<T> lt)//list& operator=(list lt){swap(lt);return *this;}~list(){clear();delete _head;_head = nullptr;}void clear(){iterator it = begin();while (it != end()){it = erase(it);}_size = 0;}void push_back(const T& x){insert(end(), x);}void push_front(const T& x){insert(begin(), x);}void pop_back(){erase(--end());}void pop_front(){erase(begin());}// pos位置之前插入iterator insert(iterator pos, const T& x){Node* cur = pos._node;Node* prev = cur->_prev;Node* newnode = new Node(x);prev->_next = newnode;newnode->_next = cur;cur->_prev = newnode;newnode->_prev = prev;++_size;return newnode;}iterator erase(iterator pos){assert(pos != end());Node* cur = pos._node;Node* prev = cur->_prev;Node* next = cur->_next;prev->_next = next;next->_prev = prev;delete cur;--_size;return next;}size_t size(){/*size_t sz = 0;iterator it = begin();while (it != end()){++sz;++it;}return sz;*/return _size;}private:Node* _head;size_t _size;};void Print(const list<int>& lt){list<int>::const_iterator it = lt.begin();while (it != lt.end()){// (*it) += 1;cout << *it << " ";++it;}cout << endl;}
}

3. list与vector的对比