public void Insert(int value)
        {
            BinaryTreeNode before = null;
            BinaryTreeNode after = this.Root;

            while (after!=null)
            {
                before = after;
                if (value<after.Value)
                {
                    after = after.LeftChild;
                }
                else if  (value>after.Value)
                {
                    after = after.RightChild;
                }
            }
            BinaryTreeNode newNode = new BinaryTreeNode(value);

            if (this.Root == null)
            {
                this.Root = newNode;
            }
            else
            {
                if (value < before.Value)
                {
                    before.LeftChild = newNode;
                }
                else
                {
                    before.RightChild = newNode;
                }
            }
        }