java练习题 交通灯亮几秒？

class jiaotongdeng{}

class Red extends jiaotongdeng{}

class Yellow extends jiaotongdeng{}

class Green extends jiaotongdeng{}

public class lianxi{

public static void draw(jiaotongdeng G)

{

if(G instanceof Red)

{

System.out.println("红灯亮45秒");

}

if(G instanceof Yellow)

{

System.out.println("黄亮5秒");

}

if(G instanceof Green)

{

System.out.println("绿亮30秒");

}

}

public static void main(String[] args)

{

draw(new Red());

draw(new Yellow());

draw(new Green());

}

}