建立链表快速查找中间结点的值并显示

#include<stdio.h>
#include<malloc.h>
#include<time.h>
#include<stdlib.h>
#include<math.h>
struct node
	{
		 int data;     //elementype表示一种数据类型，可能是int/char等等
		 struct node *next;   //next 指针，用于链表结构指向下一个节点
	};
	typedef struct node node; //重定义struct node类型为node

	int GetMidNode(node* L);
	void List(node* head);
	node* Creat(int Count);
	int Length(node *L);
	int main()
	{
	node* head;
//	head = Creat(20);
//	List(head);
//	printf("%d",Length(head));
//		printf("%d",GetMidNode(head));	
	int a;
	int Num;
	printf("1.查看链表\n2.创建链表\n3.链表长度\n4.中间节点值\n0.退出\n");
	while(1)
	{
		
	scanf("%d",&a);
	switch(a)
	{
	
		case 1:
			printf("List:\n");
			List(head);
			printf("\n");
			break;
		case 2:	
			printf("输入创建链表节点数:\n");		
			scanf("%d",&Num);
			head = Creat(Num);
			printf("\n");
			break;
		case 3:	
			printf("链表长度:\n");
			printf("%d",Length(head));
			printf("\n");
			break;
		case 4:	
			printf("中间节点值:\n");
			printf("%d",GetMidNode(head));
			printf("\n");
			break;
		case 0:	
			return 0;
	}
	
	}
	return 0;
	}
	int n;
	node* Creat(int Count)
	{
		node *p1,*p2,*head;
		n = 0;
		srand(time(NULL));//生成种子
		p1 = p2 = (node*)malloc(sizeof(node));
	//	scanf("%d",&p1->data);
		p1->data = rand()%1000;	
		head = NULL;
		while(n < Count)
		{
			n = n+1;
			if(n == 1)
			{
				head = p1;

			}
			else
			{
				p2->next = p1;

			}
			p2 = p1;
			p1 = (node*)malloc(sizeof(node));
	//		scanf("%d",&p1->data);
			p1->data = rand()%1000;	
		
		}
		p2->next = NULL;
		return(head);
	}
	void List(node* head)
	{
		node *p1;
		p1 = head;
		while(p1!= NULL)
		{
			
			printf("%d\n",p1->data);
			p1 = p1->next;
		}
	}
	int GetMidNode(node* L)
	{
		int a;
		node *search,*mid;
		mid = search = L;
		while(search->next != NULL)
		{
			if(search->next->next != NULL)
			{
				search = search->next->next;
				mid= mid->next;
			}
			else
			{
				search = search->next;
			}
		}
		a = mid->data;
		return a;
	}	
	int Length(node *L)
{
	int n = 0;
	while(L->next!= NULL)
	{
		n++;
		L = L->next;
	}
	n++;
	return n;
}
           

运行结果：