asdf

#include <stdlib.h>
#include <stdio.h>
#define LEN sizeof(struct student)
struct student
{
int num;
float score;
struct student *next;
};
 
int n;
struct student *creat(struct student *head)
{
  struct student *p1,*p2;
  n=0;
  p1=p2=(struct student *)malloc(LEN);
  scanf("%ld,%f",&p1->num,&p1->score);
  head=NULL;
  while(p1->num != 0)
  {
       n=n+1;
       if(n == 1)
       head = p1;
       else
       p2->next = p1;
       p2 = p1;
       p1 = (struct student *)malloc(LEN);
       scanf("%ld,%f",&p1->num,&p1->score);
  }
  p2->next = NULL;
  return(head);
}
 
int main()
{
 struct student *a;
 creat(a);
 struct student *p;
 p->next=a;
 int i=0;
 while(p!=NULL)
 {
        p=p->next;
        i++;
 }
 printf("%d",i);
 system("pause");
 return 0;
}