无头单链表的创建

链表是一种链式存储的线性表， 用一组地址任意的存储单元 存放线性表的数据元素， 称为存储单元的一个结点

头指针：指向第一个结点的指针

单链表的定义

typedef struct Node{
	int value;//数据域
	struct Node *next;指针域
}Node;//结构体变量

初始化

void slistinit(Node **ppfirst){
	*ppfirst = NULL;  //*ppfirst ->结构体指针
}

创建一个新节点

Node* buynode(int d){
	Node* node = (Node*)malloc(sizeof(Node));
	assert(node);
	node->value = d;
	node->next = NULL;
	return node;
}

打印单链表

void slistprint(Node** ppfirst){
	Node* cur = *ppfirst;
	while (cur){
		printf("%d->", cur->value);
		cur = cur->next;
	}
	printf("NULL/n");
}

销毁单链表

void slistDestory(Node **ppfirst){
	assert(*ppfirst);
	while (*ppfirst!=NULL){
		Node* cur = *ppfirst;
		*ppfirst = (*ppfirst)->next;
		free(cur);
	}
}

删除指定结点

void slisterase(Node **ppfirst, Node *pos){
	assert(*ppfirst&&pos);
	Node *cur = *ppfirst;
	while (cur)
	{
		if (cur == pos){

			if (*ppfirst == pos){
				*ppfirst = (*ppfirst)->next;
			}
			else{
				cur->next = pos->next;
			}
		free(pos);
		}
		cur = cur->next;
	}
}

头插

void slistpushfront(Node **ppfirst, int v){
	assert(*ppfirst);
	Node* cur=buynode(v);
	cur->next=*ppfirst;
	*ppfirst = cur;
}

头删

void slistpopfront(Node **ppfirst){
	assert(*ppfirst);
	Node *node;
	node = *ppfirst;
	*ppfirst = (*ppfirst)->next;
	free(node);
}

尾插

void slistpushback(Node **ppfirst, int v){
	Node* cur=buynode(v);
	if (*ppfirst == NULL)
	{
		*ppfirst = cur;
		return;
	}
	Node* pre = *ppfirst;
	while (pre->next)
	{
		pre = pre->next;
	}
	pre->next = cur;
}

尾删

void slistpopback(Node **ppfirst){
	assert(*ppfirst);
	//存在一个结点时
	if ((*ppfirst)->next == NULL){
		*ppfirst = NULL;
		return;
	}
	//多个节点
	Node *cur = *ppfirst;
	while (cur->next->next){
		cur = cur->next;
	}
	free(cur->next);
	cur->next = NULL;
}

查找指定元素的结点

Node* slistfind(Node** ppfirst, int v){
	assert(*ppfirst);
	Node* cur;
	while (cur){
		if (cur->value == v){
			return cur;
		}
			cur = cur->next;
	}
	return NULL;
}

在指定位置前插入一个值

void insert(Node** ppfirst, int v,int pos){
	assert(*ppfirst&&pos);
	Node* pur = buynode(v);
	Node* cur = *ppfirst;
	while (cur->next!=NULL){
		if (cur->next = pos)
		{
			cur->next = pur;
			pur ->next = pos;
		}
		cur = cur->next;
	}
}

删除第一个值为v的元素

void slistremove(Node **ppfirst, int v){
	assert(*ppfirst);
	Node *pur = NULL;
	Node *pre = *ppfirst;
	while (pre)
	{
	//第一个节点值为v
		if (pre->value == v)
	{
		
				if(*ppfirst = pre)
				{
				*ppfirst=（*ppfirst）->next;
				}else{
				pur->next=pre->next;
				}
				free(pre);
				return;
			}
		}
		else{
			pur = pre;
			pre = pre->next;
		}
	}
}

删除所有值为v的元素

Node *slistremoveelements(Node **ppfirst, int v){
	assert(*ppfirst);
	Node *pre = NULL;
	Node *pur = *ppfirst;
	while (pur){
		if (pur->value == v){
			if (NULL == pre){
				*ppfirst = pur->next;
				free(pur);
				pur = *ppfirst;//重点
			}
			else{
				pre->next = pur->next;
				free(pur);
				pur = pre->next;
			}
		}
		else{
			pre = pur;
			pur = pur->next;

		}
	}
	return *ppfirst;
}