列表建立，插入，删除

#include<stdio.h>
#include<malloc.h>
#include<stdlib.h>
#define LEN sizeof(struct student)

typedef struct student
{int num;
char name[20];
struct student *next;
}STU;
int n;


STU* creat(void)   /*创建链表函数*/
{STU *p1,*p2,*head;
n=0;
head=NULL;
p1=p2=(STU *)malloc(LEN);
scanf("%d",&p1->num);
while(p1->num!=0)
{n=n+1;
    if(n==1)head=p1;
else p2->next=p1;
p2=p1;
p1=(STU *)malloc(LEN);
scanf("%d",&p1->num);}
p2->next=NULL;
return(head);
}