list 用法与模拟

list 用法

list

list 模拟

#pragma once
#include 
namespace sjy
{
	//链表节点
	template <typename T>
	struct __list_node
	{
		__list_node(const T& val = T())
			:_prev(nullptr)
			,_next(nullptr)
			,_val(val)
		{}
		/*成员变量*/
		__list_node<T>* _prev;
		__list_node<T>* _next;
		T _val;
	};

	//迭代器
	template <typename T, typename Ref, typename Ptr>
	struct __list_iterator
	{
		typedef __list_node<T> Node;
		typedef __list_iterator<T, Ref, Ptr> self;
		__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& other) const
		{
			return _node != other._node;
		}
		bool operator==(const self& other) const
		{
			return _node == other._node;
		}
		/*成员变量*/
		Node* _node;
	};

	//list容器
	template <typename T>
	class list
	{
		typedef __list_node<T> Node;
	public:
		//迭代器相关
		typedef __list__iterator<T, T&, T*> iterator;
		typedef __list__iterator<T, const T&, const T*> const_iterator;
		iterator begin()
		{
			return _head->_next;
		}
		iterator end()
		{
			return _head;
		}

		//默认成员函数相关
		list()
			:_size(0)
		{
			_head = new Node;
			_head->_prev = _head;
			_head->_next = _head;
		}
		~list()
		{
			clear();
			delete _head;
		}
		list(const list<T>& other)
			:_size(0)
		{
			_head = new Node;
			_head->_prev = _head;
			_head->_next = _head;
			iterator it = other.begin();
			while (it != other.end())
			{
				push_back(*it);
				++it;
			}
		}
		list<T>& operator=(list<T> other)
		{
			swap(other);
			return *this;
		}

		//添加相关
		void push_back(const T& x)
		{
			Node* newnode = new Node(x);
			Node* tail = _head->_prev;
			tail->_next = newnode;
			newnode->_prev = _tail;
			newnode->_next = _head;
			_head->_prev = newnode;
			_size++;
		}
		void push_front(const T& x)
		{
			insert(begin(), x);
		}
		iterator insert(iterator pos, const T& x)
		{
			Node* newnode = new Node(x);
			Node* posptr = pos._node;
			Node* posptrprev = posptr->_prev;
			posptrprev->_next = newnode;
			newnode->_prev = posptrprev;
			newnode->_next = posptr;
			posptr->_prev = newnode;
			_size++;
			return newnode;
		}

		//删除相关
		void pop_back()
		{
			erase(--end());
		}
		void pop_front()
		{
			erase(begin());
		}
		iterator erase(iterator pos)
		{
			assert(pos != end());
			Node* posptr = pos._node;
			++pos;
			Node* posptrprev = posptr->_prev;
			Node* posptrnext = posptr->_next;
			posptrprev->_next = posptrnext;
			posptrnext->_prev = posptrprev;
			delete posptr;
			_size--;
			return pos;
		}

		//其他
		size_t size()
		{
			return _size;
		}
		void swap(list<T>& other)
		{
			std::swap(_head, other._head);
			std::swap(_size, other._size);
		}
		void clear()
		{
			iterator it = begin();
			while (it != end())
			{
				it = erase(it);
			}
		}
	private:
		Node* _head;
		size_t _size;
	};
}