这是谭浩强书上的例题，我DEBUG运行后报错，到第一个scanf那里就有问题，runtime error 请高手指点！
#if 1
#include<malloc.h>
#include<stdio.h>
#define NULL 0
#define LEN sizeof(struct student)
struct student
{
    long num;
    float score;
    struct student *next;
};
int n;
struct student *creat()
{
    struct student *head,*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);
}
void main()
{
    struct student *p;
    p=creat();
}
#endif

现在过了  奇怪