第24行修改为:scanf("%s %s %s %d",p->stu_mum,p->stu_name,p->stu_sex,&p->stu_score);
24行scanf的前面三个&号去掉
scanf()那行写错了,改为下面这样
scanf()
scanf("%s%s%s%d", p->stu_num, p->stu_name, p->stu_sex, &p->stu_score);