【C++】list（下）

#pragma once

#include <iostream>

namespace little_monster
{
	template<class T>
	struct list_node
	{
		T _data;
		list_node<T>* _prev;
		list_node<T>* _next;

		list_node(const T& x = T())
			:_data(x)
			,_prev(nullptr)
			,_next(nullptr)
		{}
	};

	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* n)
			:_node(n)
		{}

		self& operator++()
		{
			_node = _node->_next;
			return *this;
		}

		self& operator--()
		{
			_node = _node->_prev;
			return *this;
		}

		self& operator++(int)
		{
			self tmp(*this);
			_node = _node->_next;
			return tmp;
		}

		self& operator--(int)
		{
			self tmp(*this);
			_node = _node->_prev;
			return tmp;
		}

		Ref operator*()
		{
			return _node->_data;
		}

		Ptr operator->()
		{
			return &_node->_data;
		}

		bool operator!=(const self& s)
		{
			return _node != s._node;
		}

		bool operator==(const self& s)
		{
			return _node == s._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;
		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);
		}

		void Init_empty()
		{
			_head = new Node;
			_head->_next = _head;
			_head->_prev = _head;

			_size = 0;
		}

		list()
		{
			Init_empty();
		}

		list(const list<T>& lt)
		{
			Init_empty();
			for (auto e : lt)
			{
				push_back(e);
			}
		}

		void swap(list<T>& lt)
		{
			std::swap(_head, lt._head);
			std::swap(_size, lt._size);
		}

		list<int>& operator=(list<int> lt)
		{
			swap(lt);
			return *this;
		}

		~list()
		{
			clear();
			delete _head;
			_head = nullptr;
			_size = 0;
		}

		void clear()
		{
			iterator it = begin();
			while (it != end())
			{
				it = erase(it);
			}
		}

		void push_back(const T& x)
		{
			insert(end(), x);
		}

		void pop_back()
		{
			erase(--end());
		}

		void push_front(const T& x)
		{
			insert(begin(), x);
		}

		void pop_front()
		{
			erase(begin());
		}

		iterator insert(iterator pos, const T& x)
		{
			Node* cur = pos._node;
			Node* newnode = new Node(x);

			Node* prev = cur->_prev;

			prev->_next = newnode;
			newnode->_prev = prev;

			newnode->_next = cur;
			cur->_prev = newnode;

			++_size;

			return iterator(newnode);
		}

		iterator erase(iterator pos)
		{
			Node* cur = pos._node;
			Node* prev = cur->_prev;
			Node* next = cur->_next;

			delete cur;
			prev->_next = next;
			next->_prev = prev;

			--_size;

			return iterator(next);
		}

		size_t size()
		{
			return _size;
		}

	private:
		Node* _head;
		size_t _size;
	};
}

struct AA
{
	AA(int a1 = 0, int a2 = 0)
		:_a1(a1)
		, _a2(a2)
	{}

	int _a1;
	int _a2;
};

void test3()
{
	list<AA> lt;
	lt.push_back(AA(1, 1));
	lt.push_back(AA(2, 2));
	lt.push_back(AA(3, 3));

	auto it = lt.begin();
	while (it != lt.end())
	{
		std::cout << (*it)._a1<<" "<<(*it)._a2 << std::endl;
		std::cout << it->_a1 << " " << it->_a2 << std::endl;
		std::cout << it.operator->()->_a1 << " " << it.operator->()->_a1 << std::endl;

		++it;
	}
	std::cout << std::endl;

}

void test1()
{
	list<int> lt1;
	lt1.push_back(1);
	lt1.push_back(2);
	lt1.push_back(3);
	lt1.push_back(4);
	lt1.push_back(5);

	list<int> lt2(lt1);

	for (auto e : lt1)
	{
		std::cout << e << " ";
	}
	std::cout << std::endl;

	for (auto e : lt2)
	{
		std::cout << e << " ";
	}
	std::cout << std::endl;
}

void test2()
{
	list<int> lt1;
	lt1.push_back(1);
	lt1.push_back(2);
	lt1.push_back(3);
	lt1.push_back(4);
	lt1.push_back(5);

	lt1.insert(++lt1.begin(), 6);
	lt1.insert(--lt1.end(), 7);

	for (auto e : lt1)
	{
		std::cout << e << " ";
	}
	std::cout << std::endl;

	lt1.erase(++lt1.begin());
	lt1.erase(--lt1.end());

	for (auto e : lt1)
	{
		std::cout << e << " ";
	}
	std::cout << std::endl;
}

void test4()
{
	int* p = new int;
	*p = 1;
    //int* p = new int(1);
    //上面和这句结果是相同的，过程不同，一个是在构造后进行赋值，一个是初始化列表赋初值 

	AA* ptr = new AA;
	ptr->_a1 = 1;
}