数据结构＞链表，链表的增删改查，C版本单向链表，C++版本双向链表

链表的储存不连续，通过Node结点的指针指向下一个成员。
一些操作：
翻转>创建一个新结点，遍历拷贝头插。
删除特定值>使用前驱结点cur->next->value查找进行删除。
记得有结点被删除要free();

---

c版本单向链表

#include
#include

typedef size_t DataType;

//声明一个结点
typedef struct ListNode{
	ListNode * next;
	DataType value;
}Node;

//一个链表只用保存头结点的地址
typedef struct SList{
	Node* first;
}SList;

SList* InitList(SList* s)
{
	s->first = NULL;
	return s;
}

//头插
SList* PushFront(SList* s, DataType val)
{
	Node * node = (Node*)malloc(sizeof(DataType));
	node->value = val;
	node->next = s->first;
	s->first = node;
	return s;
}
//尾插
SList* PushBack(SList* s, DataType val)
{
	Node* node = (Node*)malloc(sizeof(DataType));
	node->value = val;
	node->next = NULL;
	if (s->first == NULL)
	{
		s->first = node;
	}
	else
	{
		Node* cur = s->first;
		while (cur->next != NULL)
		{
			cur = cur->next;
		}
		cur->next = node;
	}
	return s;
}
//头删
void PopFront(SList* s)
{
	assert(s != NULL);
	assert(s->first != NULL);
	Node* cur = s->first->next;
	free(s->first);
	s->first = cur;
	return;
}
//尾删
void PopBack(SList* s)
{
	assert(s != NULL);
	assert(s->first != NULL);
	Node* cur = s->first;
	if (s->first->next == NULL)
	{
		free(s->first);
		s->first = NULL;
		return;
	}
	while (cur->next->next != NULL)
	{
		cur = cur->next;
	}
	free(cur->next);
	cur->next = NULL;
	return;
}
int main()
{
	SList list;
	InitList(&list);
	PushFront(&list, 4);
	PushFront(&list, 5);
	PushFront(&list, 7);
	PushBack(&list, 8);
	PushBack(&list, 10);
//	PopFront(&list);
//	PopBack(&list);

	return 0;
}

---

C++版本双向链表

class Node {

public:
	Node* _previous;
	Node* _next;
	int _data;
};

class List {
public:
	List(int length) :
		_length(length),
		_head(new Node),
		_tail(new Node)
	{
		_head->_previous = nullptr;
		_head->_next=_tail;
		_tail->_previous = _head;
		_tail->_next = nullptr;
		_head->_data = 0;
		Node* temp(new Node);
		temp = _head;
		for (int i=0; i < _length; ++i)
		{
			Node* cur(new Node);
			temp->_next = cur;
			cur->_previous = temp;
			cur->_data = i+10;
			temp = cur;
			temp->_next = nullptr;
			_tail = temp;
		}
	}

	void print()
	{
		for (Node* temp = _head->_next; temp != nullptr; temp = temp->_next)
		{
			cout << temp->_data << " ";
		}
		cout << endl;
	}
	void push_back(int number)
	{
		Node* cur(new Node);
		cur->_data = number;
		cur->_previous = _tail;
		_tail->_next = cur;
		cur->_next = nullptr;
	}
	void delet(Node* node)
	{
		Node* temp=node->_previous;
		temp->_next = node->_next;
		node->_next->_previous = temp;
		delete node;
	}
public:
	Node* _head;
	Node* _tail;
	int _length;

};
void testNode()
{
	List list(8);
	Node* node3 = list._head->_next->_next->_next;
	list.delet(node3);
	list.print();
	list.push_back(20);
	list.print();
}
int main()
{
	testNode();
	return 0;

}```