CalcPerimiter - MMN15

    public double calcPerimeter() {
        double peri = 0;

        if (head.getNext() == null) {
            return peri;
        } else if (head.getNext().getNext() == null) {
            return head.getPoint().distance(head.getNext().getPoint());
        }

        PointNode iterable = head;

        while (iterable.getNext().getNext() != null) {
            if (iterable.getNext() == null) {
                peri += iterable.getPoint().distance(head.getPoint());
            } else {
                peri += iterable.getPoint().distance(iterable.getNext().getPoint());
                iterable = iterable.getNext();
            }
        }

        return peri;
    }