#include<stdio.h>
#include<stdlib.h>
#define NULL 0
struct student{
    int data;
    struct student *next;
};

int main()
{
    struct student *pnew,*head;
    int i,num;
    pnew=(struct student *)malloc(sizeof(struct student));//开辟首结点
    pnew=head;
   
   
    for(i=0;i<=4;i++)//输入五个学号
    {
       scanf("%d",&num);
       pnew->data=num;
       pnew->next=(struct student *)malloc(sizeof(struct student));//开辟下一个结点
           if(i==4)pnew->next=NULL;
           else pnew=pnew->next;

    }
    pnew=head;
    while(pnew!=NULL)
    {
      printf("%d",pnew->data);
      pnew=pnew->next;
      printf("\n");
    }   
     return 1;  
}//创建一个链表！！！

int main(){    struct student *pnew,*head;    int i,num;    pnew=(struct student*)malloc(sizeof(struct student));//开辟首结点    pnew=head;//这句错了，应该是head=pnew;

太谢谢了！！！

#include<stdio.h>
#include<stdlib.h>
#define NULL 0
struct student{
    int data;
    struct student *next;
};

int main()
{
    struct student *pnew,*head,*temp;//head为头指针，temp为临时指针，pnew为当前指针
    int i,num;
    head=NULL;//首先将头指针置空
    printf("输入五个学号:");
    for(i=0;i<=4;i++)//输入五个学号
    {
        pnew=(struct student *)malloc(sizeof(struct student));//每次循环都为当前指针分配空间，记录当前数据
        scanf("%d",&num);
        pnew->data=num;
        pnew->next=NULL;//同时将pnew->next置空
        if(head==NULL)//如果头指针为空，把当前指针指向头指针
            head=pnew;
        else//否则把当前指针指向临时指针
            temp->next=pnew;
        temp=pnew;
    }
    while(head!=NULL)
    {
        printf("%d  ",head->data);
        head=head->next;
    }
    printf("\n");
    return 1;  
}
这也是一种链表写法，希望你有用。

你的temp用得怎么莫名其妙的。