萌新小白昨天学习了多态下的 instanceof关键字 然后就试着写了如下代码：
public class ABtest{

public static void main(String[] args){
ABtest ab=new ABtest();

Boo b= new Aoo();
Boo b1=new Coo();
ab.display(b);
ab.display(b1);

}

public void display(Boo b){
if(b instanceof Aoo){
Aoo a=(Aoo)b;
a.show();
}
else if(b instanceof Coo){
Coo c=(Coo)b;
c.show();

}
}

}
class Boo{
public void show(){
System.out.println("xxx");
}
}
class Aoo extends Boo{
public void show(){
System.out.println("yyyy");
}
}
class Coo extends Boo{
public void show(){
System.out.println("zzzzz");
}
}
愣了3秒…