class A
{
    int x=3;
    public void m()
    {
        x++;
        System.out.println("the x of A is "+x);
    }
}
class B extends A
{
    double x=20.67;  //也可定義為其它類型，如double x;
    public void n()
    {
        x--;
        System.out.println("the x of B is "+x);
    }
    public void usehide()
    {
        System.out.println("the x of superclass is "+(--super.x));
    }
    public static void main(String[] args)
    {
        B b = new B();
        b.n();
        b.usehide();
        b.m();
        	
    }
}