【单选题】类Teacher和Student是类Person的子类; Person p; Teacher t; Student s; //p, t and s are all non-null. if(t instanceof Person) { s = (Student)t; } 最后一句语句的结果是:
【单选题】类 Teacher 和 Student 是类 Person 的子类 Person p; Teacher t; Student s; //p,t and s are all non-null. if(t instanceof Person) {s=(Student)t;} 最后一句语句的结果是: