C语言，程序输出链表后卡死？

Question

#include
#include

struct student 
{
    int num;
    char name[20];
    struct student *pnext;
};
int n;
struct student *creat()
{
    struct student *head;
    struct student *pnew,*pend;
    head=NULL;
    n=0;
    pnew=pend=(struct student *)malloc(sizeof(struct student));
    scanf("%d",&pnew->num);
    scanf("%s",&pnew->name);
    while(pnew->num!=0)
    {
        n++;
        if(n==1)
            head=pnew;
        else
        {   pend->pnext=pnew;
            pend=pnew;
        }
        pnew=(struct student *)malloc(sizeof(struct student));
        scanf("%d",&pnew->num);
        scanf("%s",&pnew->name);
    }

    pend->pnext=NULL;
    return head;
}
void print(struct student *head)
{
    struct student *temp;
    temp=head;
    while(temp->num!=0)
    {
        printf("%d\n",temp->num);
        printf("%s\n",temp->name);
        temp=temp->pnext;
    }
}
void main()

{
struct student *phead;
phead=creat();
print(phead);
}

Answer 1

 while(temp->num!=0)
->
while(temp != NULL && temp->num!=0)