java的向下转型

class A{

public void fun1(){


System.out.println("A-->public void fun1()");


}


public void fun2(){


this.fun1();


}

}

class B extends A{


public void fun1(){


System.out.println("B-->public void fun1()");


}


public void fun3(){


System.out.println("B-->public void fun3()");


}

}

class C extends A{


public void fun1(){


System.out.println("C-->public void fun1()");


}


public void fun4(){


System.out.println("C-->public void fun4()");


}

}

public class Demo03{


public static void main(String args[]){


fun(new B());


fun(new C());


}


public static void fun(A a){


//a.fun1();


if(a instanceof B){


B b = (B)a;


b.fun3();


}


if(a instanceof C){


C c = (C)a;


c.fun4();


}


}

}