程序代码：

#include<stdio.h>
#define LEN sizeof(struct student)
struct student
{
    long num;
    float score;
    struct student *next;
};
int n;
struct student *creat(void)
{
    struct student *head;
    struct student *p1,*p2;
    n=0;
    p1=p2=(struct student *)malloc(LEN);//这里报错了！不知道为什么
    scanf("%lf,%f",&p1->num,&p1->score);
        head=NULL
        while(p1->num!=0)//这里也报错了
        {
            n=n+1;
            if(n==1)head=p1;
            else p2->next=p1;
            p2=p1;
            p1=(struct student *)malloc(LEN);
        }
        p2->next=NULL;
        return(head);
}