public class Main {     //  主函数
    public static void main(String[] args) {
        Student[] stu = new Student[]{
                new Ben("张三", 19, 002, "本科生"),
                new Zuan("李四", 18, 003, "专科生"),
                new Yan("Sun", 22, 001, "研究生")
        };
        
        for (int i = 0; i < stu.length; i++) {
            stu[i].study();
        }
    }
}