public T predecessor(T x) {
		BSTNode<T> pre = predecessor(x, root, null);
		if (pre == null) {
			System.out.println("Elemento " + x + " no encontrado");
			return null;
		}
		else
			return pre.nodeValue;
	}

	private BSTNode<T> predecessor(T x, BSTNode<T> curr, BSTNode<T> ascLeft) {
		if (curr == null) return null;
		int resC = ((Comparable)curr.nodeValue).compareTo((Comparable)x);
		if (resC == 0) {
		if (curr.left != null) return findMax(curr.left);
		else return ascLeft;
		} else if (resC < 0) return predecessor(x, curr.right, curr);
		else return predecessor(x, curr.left, ascLeft);
	}