public class Point
{
    private final int x;
    private final int y;
    public Point(int x, int y)
    {
        this.x = x;
        this.y = y; 
    }
    public Point()
    {
        this(0,0);  //calls sibling constructor
    }
    public Point reflectionAcrossX()
    {
        return new Point(x, -y);
    }
    @Override
    public String toString()
    {
        return String.format("(%s, %s)", x, y);
    }
    @Override
    public boolean equals(Object o)
    {
        if(this == o)
        {
            return true;
        }
        if(!(o instanceof Point))
        {
            return false;
        }
        //o must be a Point!
        Point that = (Point) o;
        return x == that.x && y == that.y;
    }
    public double distanceTo(Point that)
    {
        return Math.hypot(x - that.x, y - that.y);
    }
}