Java 进阶

class Point {

    double x;
    double y;

    Point() {
        x = 0;
        y = 0;
    }

    boolean samePlace(Point p) {
        return (x == p.x) && (y == p.y);
    }

}

class PtSubClassextends Point {

    int aNewField;
    boolean samePlace (Pointp2) {
        return false;
    }
    void sayHi() {
        System.out.println("hello");
    }
}