1_链表的创建，打印，添加

struct student{
	int num;
	struct student *pnext;

};

//创建链表
Stu *createLinkedList(Stu *head,int len){
	if (head==NULL)
	{
		return NULL;
	}
	Stu *last=head;
	//last->num=10;
	for (int i=1;i<=len;i++)
	{
		last->pnext=(Stu*)malloc(sizeof(Stu));
		last->pnext->num=i;
		last=last->pnext;
	}
	last->num=len-5;
	last->pnext=NULL;
	return head;
}

    

//打印链表
void print_list(Stu *head){
	if (head==NULL)
	{
		return ;
	}
	Stu *last=head->pnext;
	while (last!=NULL)
	{
		printf("%d\t",last->num);
		last=last->pnext;
	}

}

 

//从头插入
int addNode(Stu *head,int value){
	if (head==NULL)
	{
		return -1;
	}
	Stu *last=head;
	Stu *newNode=(Stu*)malloc(sizeof(Stu));
	if (newNode==NULL)
	{
		return -1;
	}
	newNode->num=value;
	newNode->pnext=head->pnext;
	head->pnext=newNode;

	//newNode->pnext=NULL;
	return 0;
}