/*保存信息*/
void save_file(struct student *head)
{
    FILE *fp;
    char filename[20];
    struct student *p;
    fflush(stdin);
    printf("plase input 要保存的文件名:");
    scanf("%s",filename);
    fflush(stdin);
    if((fp=fopen(filename,"wt")==NULL))
    {
        printf("写文件错误,按任意键退出!");
        getch();
        exit(1);
    }
    for(p=head->next;p->next;p=p->next)
    {
       fwrite(p,sizeof(struct student),1,fp);
        printf("\n文件已经成功保存,按任意键返回!");
        getch();
        fclose(fp);
    }
}
怎么不行啊

while ((p=p->next) != NULL)
{
    fwrite(p,sizeof(struct student),1,fp);
}
printf("\n文件已经成功保存,按任意键返回!");
getch();
fclose(fp);