C 循环单链表

#include<stdio.h>
#include<stdlib.h>

struct listnode *heap;

typedef struct listnode
{
	int data;
	struct listnode *next;
}listnode;

listnode * creatlist()
{
	listnode * temp;
	listnode *p;
	listnode *a;
	int i;
	temp = (listnode*)malloc(sizeof(listnode));
	p = temp;
	heap = temp;
	p->data = 1122;   //头结点，不初始化值一般为0，一般冲下一个节点开始
	for(i=1;i<11;i++)
	{
		a = (listnode*)malloc(sizeof(listnode));
		a->data = i;
		a->next = NULL;

		p->next = a;
		printf("%d\t",p->data);
		p=p->next;
	}
	printf("\n");
	return temp;
}

void  outputlist(listnode *p)
{
	struct listnode *h;
	h = p;
	int i =0;
	if(h == NULL)
	{
		printf("the list is null\n");
		return;
	}
	while(h!=NULL)
	{
		printf("%d\t",h->data);
		h=h->next;
		sleep(1);
		if(0 == (i%10))
		{
			printf("\n");
			i = 0;
		}
		i++;
	}
	printf("\n");
	return;
}

listnode * insertlist(int sum,int data,struct listnode *p)
{
	int i = 0;
	listnode *h;
	h = (listnode *)malloc(sizeof(listnode));
	h->data = data;
	for(i = 1;i<sum;i++)
	{
		p = p->next;
	}
	h->next = p->next;
	p->next = h;
	return p;
}

listnode * deletelist(int sum,struct listnode *p)
{
	int i = 0;

	for(i = 1;i<sum;i++)
	{
		p = p->next;
	}

	p->next = p->next->next;
	return p;
}
listnode * looplist(struct listnode *p)
{

		while(p->next != NULL)
		{
			p=p->next;
		}	
		p->next = heap->next;
	printf("22222\t");
	return p;
}

int main()
{
	int data,num;
	num = 5;
	data = 2021;
	listnode *p;
	printf("creat list...\n");
	p = creatlist();
	printf("print list...\n");
	outputlist(p);
	printf("insert list...\n");
	insertlist(num,data,p);
	printf("print list...\n");
	outputlist(p);
	printf("delete list...\n");
	deletelist(num,p);
	printf("print list...\n");
	outputlist(p);
	printf("loop list...\n");
	looplist(p);
	printf("print list...\n");
	outputlist(p);
	// printf("insert list...\n");
	// insertlist(7,207,p);
	// printf("insert list...\n");
	// insertlist(9,209,p);
	// outputlist(p);


	return 0;
}