for语句
.......\d.class
.......\d.java
.......\新建文本文档.txt
if
..\a.class
..\a.java
shuzu
.....\shuzu.class
.....\shuzu.java
.....\新建文本文档.txt
switch
......\a.class
......\a.java
......\新建文本文档.txt
对象数组
........\a.class
........\a.java
........\Student.class
........\新建文本文档.txt