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From: "Gavino" <invalid@invalid.invalid>
Newsgroups: comp.lang.java.programmer
Subject: Re: Programming question determining two circle's relation
Date: Sat, 30 Apr 2011 17:51:37 +0200
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"byhesed" <byhesed@gmail.com> wrote in message
news:2bc6aa50-5730-4057-b016-3a2b7154f0e9@f15g2000pro.googlegroups.com...
> Here is the correct answer.
>
> public boolean contains(Circle2D circle) {
> double distance = Math.pow(circle.x - getX(), 2.0) +
> Math.pow(circle.y - getY(), 2.0);
> if (distance <= (Math.pow(radius, 2.0) - Math.pow(circle.radius,
> 2.0)))
> return true;
> else
> return false;
>
> }
>
> public boolean overlaps(Circle2D circle) {
> double distance = Math.pow(circle.x - getX(), 2.0) +
> Math.pow(circle.y - getY(), 2.0);
> if (distance < Math.abs(Math.pow(radius, 2.0) -
> Math.pow(circle.radius, 2.0)))
> return true;
>
> else
> return false;
> }

That's still wrong.
'contains' should have
return Math.sqrt(distance) <= radius-circle.radius;
and 'overlaps' should have
return Math.sqrt(distance) <= radius+circle.radius;
as can easily be seen by drawing a simple picture.

Here I have retained your name 'distance' for what is actually the square of
the distance.