数据结构之单向链表

//
#include<stdio.h>
#include<stdlib.h>
#define LEN sizeof(struct node)
struct node
{
	int num;
	struct node*next;
};
int n=0;
struct node*()
{
	struct node*head,*p1,*p2;
	head=NULL ;
	p1=p2=(struct node*)malloc(LEN);
	printf("please put in data:n");
	scanf_s("%d",&p1->num);
	while(p1->num!=0)
	{
		n++;
		if(n==1)head=p1;
		else
			p2->next=p1;
		p2=p1;
		p1=(struct node*)malloc(LEN);
		printf("please put in data:n");
		scanf_s("%d",&p1->num);
	}
	p2->next=NULL;
	return head;
}
void print(struct node*head)
{
	struct node*p=head;
	while(p!=NULL)
	{
		printf("%dt",p->num);
		p=p->next;
	}
}
void clear(struct node*head)
{
	struct node*p1,*p2;
	p1=p2=head;
	while(p1!=NULL)
	{
		p1=p2->next;
		free(p2);
		p2=p1;
	}
}
int _tmain(int argc, _TCHAR* argv[])
{
	struct node*p=NULL;
	int i;
	printf("tt1.创建链表n");
	printf("tt2.输出链表n");
	printf("tt3.清空链表n");
	while(1)
	{
		printf("请输入:n");
		scanf_s("%d",&i);
		switch(i)
		{
		case 1:p=create();printf("创建成功n");break;
		case 2:print(p);break;
		case 3:clear(p);break;
		default:return 0;
		}
	}
	return 0;
}