C语言：预处理

文章目录

• list
• • 介绍
  • 节点类(listNode)
  • __list__iterator(迭代器类)
  • • operator->
  • list的成员函数
  • • empty_init() 初始化节点
    • list(list<T>& lt) 拷贝构造
    • clear() 清除链表
    • ~list() 析构
    • insert() 插入
    • erase() 删除
    • push_back() 尾插
    • push_front() 头插
    • pop_back() 尾删
    • pop_front() 头删
    • begin() 头节点
    • end() 尾节点
• 总结

list

介绍

节点类(listNode)

template<class T>
//链表节点类
struct listNode
{
	listNode<T>* _next;//指向下一个节点
	listNode<T>* _prev;//指向上一个节点
	T date;//内容
	
	listNode(const T& x = T())
		:_next(nullptr)
		,_prev(nullptr)
		,date(x)
	{}
};

__list__iterator(迭代器类)

//正向迭代器类
//Ref 来区别const和普通
template<class T,class Ref,class Ptr>
struct __list__iterator
{
	typedef listNode<T> Node;//减少代码
	typedef __list__iterator<T,Ref> self;//来控制他的类别
	Node* _node;//节点
	__list__iterator(Node* node)
		:_node(node)
	{}
	//++it
	self& operator++()
	{
		_node = _node->_next;
		return *this;
	}
	//it++
	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;
	}
	Ref operator*()
	{
		return _node->date;
	}
	bool operator!=(const self& s)
	{
		return _node != s._node;
	}
	bool operator==(const self& s)
	{
		return _node == s._node;
	}
	Ptr operator->()
	{
		return &_node->date;
	}
};

operator->

struct MyStruct
{
	int _a1;
	int _a2;
	MyStruct(int _a1 = 1, int _a2 = 1)
		:_a1(_a1)
		,_a2(_a2)
	{

	}
};
void test2()
{
	list<MyStruct> s;
	s.push_back(MyStruct());
	s.push_back(MyStruct());
	s.push_back(MyStruct());//插入的是一个类
	list<MyStruct>::iterator lt = s.begin();
	while (lt != s.end())
	{
		cout << lt->_a1<<":"<< lt->_a2 << " ";//读这个类里面的内容
		//lt->_a1 的本质是 lt.operator->()->_a1; 特殊处理
		++lt;
	}
}

list的成员函数

	typedef listNode<T> Node;
	typedef __list__iterator<T,T&,T*> iterator;
	typedef __list__iterator<T,const T&,const T*> const_iterator;
	typedef Reverselterator<T, T&, T*> reverse_iterator;

empty_init() 初始化节点

void empty_init()//初始化节点
{
	_head = new Node;
	_head->_next = _head;
	_head->_prev = _head;
}

list(list& lt) 拷贝构造

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

clear() 清除链表

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

~list() 析构

~list()
{
	clear();
	delete _head;
}

insert() 插入

iterator insert(iterator pos, const T& x)//在摸个节点之前插入
{
	Node* cur = pos._node;//插入的位置
	Node* prev = cur->_prev;//插入的下一个位置
	Node* newnode = new Node(x);//构成节点
	prev->_next = newnode;
	newnode->_prev = prev;
	newnode->_next = cur;
	cur->_prev = newnode;
	return newnode;
}

erase() 删除

iterator erase(iterator pos)
{
	assert(pos !=end());//判断他不是哨兵位
	Node* cur = pos._node;
	Node* prev = cur->_prev;
	Node* next = cur->_next;
	prev->_next = next;
	next->_prev = prev;

	delete cur;
	return next;
}

push_back() 尾插

void push_back(const T& x)//尾插
{
	/*Node* newnode = new Node(x);
	Node* tail = _head->_prev;//链表尾部节点
	tail->_next = newnode;
	newnode->_prev = tail;
	newnode->_next = _head;
	_head->_prev = newnode;*/
	insert(end(), x);
}

push_front() 头插

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

pop_back() 尾删

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

pop_front() 头删

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

begin() 头节点

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

end() 尾节点

const_iterator end() const
{
	return _head;
}

总结

template<class T>
//链表节点类
struct listNode
{
	listNode<T>* _next;
	listNode<T>* _prev;
	T date;
	
	listNode(const T& x = T())
		:_next(nullptr)
		,_prev(nullptr)
		,date(x)
	{}
};
	//正向迭代器类
	//Ref 来区别const和普通
	template<class T,class Ref,class Ptr>
	struct __list__iterator
	{
		typedef listNode<T> Node;
		typedef __list__iterator<T,Ref> self;
		Node* _node;
		__list__iterator(Node* node)
			:_node(node)
		{}
		//++it
		self& operator++()
		{
			_node = _node->_next;
			return *this;
		}
		//it++
		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;
		}
		Ref operator*()
		{
			return _node->date;
		}
		bool operator!=(const self& s)
		{
			return _node != s._node;
		}
		bool operator==(const self& s)
		{
			return _node == s._node;
		}
		Ptr operator->()
		{
			return &_node->date;
		}
	};
template<class T>
class list
{
	typedef listNode<T> Node;
public:
	typedef __list__iterator<T,T&,T*> iterator;
	typedef __list__iterator<T,const T&,const T*> const_iterator;
	typedef Reverselterator<T, T&, T*> reverse_iterator;
	const_iterator begin() const
	{
		return _head->_next;
	}
	const_iterator end() const
	{
		return _head;
	}
	iterator begin()
	{
		//return iterator(_head->_next);
		return _head->_next;
	}
	iterator end()
	{
		//return iterator(_head);
		return _head;
	}
	iterator rbegin()
	{
		return end();
	}
	iterator rend()
	{
		return begin();
	}
	void empty_init()//初始化节点
	{
		_head = new Node;
		_head->_next = _head;
		_head->_prev = _head;
	}
	list()
	{
		empty_init();
	}
	list(list<T>& lt)
	{
		empty_init();
		for (const auto& ch : lt)
		{
			push_back(ch);
		}
	}
	~list()
	{
		clear();
		delete _head;
	}
	void clear()
	{
		iterator it = begin();
		while (it != end())
		{
			it = erase(it);
		}
	}
	void swap(list<T>& lt)
	{
		std::swap(_head, lt._head);
	}
	list<T>& operator=(list<T> lt)
	{
		swap(lt);
		return *this;
	}
	void push_back(const T& x)//尾插
	{
		/*Node* newnode = new Node(x);
		Node* tail = _head->_prev;//链表尾部节点
		tail->_next = newnode;
		newnode->_prev = tail;
		newnode->_next = _head;
		_head->_prev = newnode;*/
		insert(end(), x);
	}
	void push_front(const T& x)//头插
	{
		insert(begin(), x);
	}
	void pop_back()//尾删
	{
		erase(--end());
	}
	void pop_front()//头删
	{
		erase(begin());
	}
	iterator insert(iterator pos, const T& x)//在摸个节点之前插入
	{
		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 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 next;
	}
private:
	Node* _head;//哨兵位
};