文件操作问题。fscanf读取为负数？

Question

struct student *read_file(){
int i=0;
struct student *p1=NULL,*head=NULL,*p2=NULL;
FILE *pfile;
pfile = fopen("student.txt","r");
if(pfile == NULL)
{
printf("+                     未发现存档                    +\n");
return 0;}
while(!feof(pfile)){
p1 = (struct student*)malloc(LEN);
fscanf(pfile,"%d%d%d%s%s%s%s%s",&p1->idnum,&p1->cardnum,&p1->date,p1->school,p1->sex,
&p1->major,&p1->iden,p1->name);    
p1->next=NULL;    
if(i==0) head=p1;    
else p2->next=p1;    
p2=p1;    
i++;}
fclose(pfile);
printf("+                     读档成功                     +\n");
return head;}

我的idnum是201820020304 这么长的，可是输入的却是负数，请教大佬