C++-list模拟实现

list.h

#pragma once
#include<iostream>
#include<assert.h>

using namespace std;

namespace List
{
	template<class T>
	struct ListNode
	{
		ListNode<T>* _next;
		ListNode<T>* _prev;

		T _data;
		ListNode(const T& data = T())
			:_next(nullptr)
			, _prev(nullptr)
			, _data(data)
		{
		}
	};

	template<class T, class Ref, class Ptr>
	struct ListIterator
	{
		typedef ListNode<T> Node;
		Node* _node;
		typedef ListIterator<T, Ref, Ptr> Self;

		ListIterator(Node* node)
			:_node(node)
		{
		}


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

		Self operator++()
		{
			_node = _node->_next;  // 修改 _node 指针
			return *this;
		}

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

		bool operator!=(const Self& it)
		{
			return _node != it._node;
		}

		bool operator==(const Self& it)
		{
			return _node == it._node;
		}
	};

	template<class T>
	class list
	{
		typedef ListNode<T> Node;
	public:
		typedef ListIterator<T, T&, T*> iterator;
		typedef ListIterator<T, const T&, const T*> const_iterator;

		list()
		{
			_head = new Node();
			_head->_next = _head;
			_head->_prev = _head;
		}


		iterator begin()
		{
			return iterator(_head->_next);
		}

		const_iterator begin() const
		{
			return const_iterator(_head->_next);
		}

		iterator end()
		{
			return iterator(_head);
		}

		const_iterator end() const
		{
			return const_iterator(_head);
		}

		void push_back(const T& x)
		{

			Node* newnode = new Node();
			newnode->_data = x;
			Node* prev = _head->_prev;

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

		void pop_back()
		{
			Node* prev = _head->_prev;
			prev->_prev->_next = _head;
			_head->_prev = prev->_prev;
			delete prev;
		}

		void pop_front()
		{
			Node* next = _head->_next;
			_head->_next = next->_next;
			next->_next->_prev = _head;
			delete next;
		}

		void push_front(const T& x)
		{
			Node* newnode = new Node(x);
			Node* next = _head->_next;
			_head->_next=newnode;
			newnode->_next = next;
			newnode->_prev = _head;
			next->_prev = newnode;
		}

		iterator insert(iterator pos, const T& x)
		{
			Node* cur = pos._node;
			Node* prev = cur->_prev;
			Node* newnode = new Node(x);
			prev->_next = newnode;
			newnode->_prev = prev;
			newnode->_next = cur;
			cur->_prev = newnode;
			return iterator(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;
			return iterator(next);
		}

		iterator find(iterator pos1, iterator pos2, T x)
		{
			while (pos1 != pos2)
			{
				if (pos1._node->_data == x)
				{
					return pos1;
				}
				++pos1;
			}
			return end();
		}
		  
	private:
		Node* _head;
	};

};

测试代码

#include"mylist.h"

using namespace List;
void list_test1(list<int> lt)
{
	//增删查
	lt.push_back(1);
	lt.push_back(2);
	lt.push_back(3);
	lt.push_back(4);
	lt.pop_back();
	lt.pop_front();
	lt.push_front(10);
}

void list_test2()
{
	//迭代器测试
	list<int> lt;
	lt.insert(lt.end(), 1);
	lt.insert(lt.end(), 2);
	lt.insert(lt.end(), 3);
	lt.insert(lt.end(), 4);


	list<int>::iterator it = lt.begin();
	while (it != lt.end())
	{
		*it += 10;
		++it;
	}

	for (auto e : lt)
	{
		cout << e << ' ';
	}

	// 查找数据
	it = lt.begin();//上面已经++为end()了,原来的迭代器不再指向begin()
	list<int>::iterator it2 = lt.find(it, lt.end(), 12);
	if (it2 != lt.end()) {
		cout << "找到的数据为" << *it2 << endl;  // 使用 *it2 来访问数据
	}
	else {
		cout << "没有找到数据" << endl;
	}
}


int main()
{
	list<int> lt;
	list_test2();


	return 0;
}