class A{                    // 定义类A

    public void fun1(){        // 定义fun1()方法

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

    }

    public void fun2(){

        this.fun1() ;        // 调用fun1()方法

    }

};

class B extends A{

    public void fun1(){        // 此方法被子类覆写了

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

    }

    public void fun3(){

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

    }

};

public class InstanceofDemo01{

    public static void main(String asrgs[]){

        A a1 = new B() ;        // 通过向上转型实例化对象

        System.out.println("A a1 = new B()：" + (a1 instanceof A)) ;

        System.out.println("A a1 = new B()：" + (a1 instanceof B)) ;

        A a2 = new A() ;        // 通过向上转型实例化对象

        System.out.println("A a2 = new B()：" + (a2 instanceof A)) ;

        System.out.println("A a2 = new B()：" + (a2 instanceof B)) ;

    }

};

class A{                    // 定义类A

    public void fun1(){        // 定义fun1()方法

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

    }

    public void fun2(){

        this.fun1() ;        // 调用fun1()方法

    }

};

class B extends A{

    public void fun1(){        // 此方法被子类覆写了

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

    }

    public void fun3(){

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

    }

};

class C extends A{

    public void fun1(){        // 此方法被子类覆写了

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

    }

    public void fun5(){

        System.out.println("C --> public void fun5(){}") ;

    }

};

public class InstanceofDemo02{

    public static void main(String asrgs[]){

        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.fun5() ;

        }

    }

};