LCRS트리 PreOrder with Stack

        public void PreOrder()
        {
            Stack stack = new Stack();
            if (this.Root == null)
            {
                Console.WriteLine("노드가 없습니다.");
            }
            else
            {
                Node temp = this.Root;
                while(true)
                {
                    if (temp != null)
                    {
                        Console.Write("{0} ", temp.Data);
                        stack.Push(temp);
                        if (temp.Left == null)
                        {
                            temp = stack.Pop().Right;
                            while (stack.Count() > 0 && temp == null)
                            {
                                temp = stack.Pop().Right;
                            }
                        }
                        else
                        {
                            temp = temp.Left;
                        }
                    }
                    else
                    {
                        Console.WriteLine();
                        return;
                    }
                }
            }
        }