#include<stdio.h>
#include<stdlib.h>
struct student
{
    long num;
    float score;
    struct student * next;
};
int n=0;//结点的个数
struct student * creat(void)
{
    struct student * head;
    struct student * p;
    struct student * tail;
    head=NULL;
    p=(struct student *)malloc(sizeof(struct student));//开辟一个结点
    scanf("%ld %f",&p->num,&p->score);
    while(p->num!=0)
        if(head==NULL)
            head=p;//指向新的结点
            //作为表尾的结点（最后的结点）
        else
        tail->next=p;//当前的最后一个结点指向新生成的结点
        
        tail=p;
    p=(struct student *)malloc(sizeof(struct student));
    scanf("%ld %f",&p->num,&p->score);
}
return head;
}
main(){
   struct student * head=create();
   struct student * p=head;
   while(p!=NULL)
   {
      printf("node[num=%ld,score=%f]\n",p->num,p->score);
      p=p->next;
      }
   return 0;
}

你创建链表时没有在链表尾指向Null

谢谢