建立简单动态链运行后没有结果（C语言）在线等。谢谢！

Question

#include<stdio.h>#include<stdlib.h>#define LEN sizeof(struct student)struct student{    long num;    float score;    struct student *next;};int n;struct student *creat(void){    struct stduent *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 *pt;    pt=creat();    printf("\n num:%ld\n score:%5.1f\n",pt->num,pt->score);    return 0;}