public class Point {
    double x=0.0;
    double y=0.0;

    // right is positive, left is negative 
    void moveRight(double howFar) {
	x += howFar;
    }
    void moveLeft(double howFar) {
	x -= howFar;
    }

    // up is positive, down is negative
    void moveUp(double howFar) {
	y += howFar;
    }
    void moveDown(double howFar) {
	y -= howFar;
    }

    public String toString() {
	return ( "Point(" + x + ", " + y + ")" );
    }

    public static void main(String[] args) {
	Point p = new Point();
	Point q = new Point();
	Point p_alias = p;

	p.x = 12.4;
	p.y = 12.4;

	q.moveLeft(12.4);
	q.moveDown(12.4);

	p_alias.moveUp(5.0);

	System.out.println("p=" + p + "  q=" + q + "   p_alias=" + p_alias);
    }

}