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