#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 student *head;
    struct student *p1, *p2;
    n = 0;
    p1 = p2 = (struct student *)malloc(len);
    scanf_s("%ld%f", &p1->num, &p1->score);
    while (p1->num != 0)
    {
        n = n + 1;
        if (n == 1)
            head = p1;
        else
            p2->next = p1;
        p2 = p1;
        p1 = (struct student *)malloc(len);
        scanf_s("%ld%f", &p1->num, &p1->score);
    }
    p2->next = NULL;
    return head;
}

int main()
{
    struct student *pt;
    pt = creat();
    printf("\nnum:%ld\nscore:%5.1f\n", pt->num, pt->score);
    return 0;
}

没什么大问题，可能是scanf_s的原因，这是vs2005以上版本提供的函数，将其修改为scanf就行了（如果scanf_s输入字符，则有两个参数，改成scanf需去掉第二个参数）。另申请动态内存，用完需要释放，main函数修改如下，可显示链表内数据同时注销掉creat函数申请的所有链表节点：
int main()
{
    struct student *pt,*p;
    pt = creat();
    while (pt!=NULL)
    {
        printf("\nnum:%ld\nscore:%5.1f\n", pt->num, pt->score);
        p=pt;
        pt=pt->next;
        free(p);
    }
    return 0;
}