C#实现二叉树数据结构

// Binary Tree的结点类  
    class Node
    {
        public int Data { get; set; }
        public Node LeftSubNode { get; set; }
        public Node RightSubNode { get; set; }

        // 结点为自己追加子结点（与向左/向右追加结合，形成递归）  
        public void Append(Node subNode)
        {
            if (subNode.Data <= this.Data)
            {
                this.AppendLeft(subNode);
            }
            else
            {
                this.AppendRight(subNode);
            }
        }

        // 向左追加  
        public void AppendLeft(Node subNode)
        {
            if (this.LeftSubNode == null)
            {
                this.LeftSubNode = subNode;
            }
            else
            {
                this.LeftSubNode.Append(subNode);
            }
        }

        // 向右追加  
        public void AppendRight(Node subNode)
        {
            if (this.RightSubNode == null)
            {
                this.RightSubNode = subNode;
            }
            else
            {
                this.RightSubNode.Append(subNode);
            }
        }

        // 结点显示自己的数据  
        public void ShowData()
        {
            Console.WriteLine("Data={0}", this.Data);
        }
    }

    // Binary Tree类  
    class Tree
    {
        // 根结点  
        public Node Root { get; set; }

        // 以某结点为起点，插入结点  
        public void Insert(Node newNode)
        {
            if (this.Root == null)
            {
                this.Root = newNode;
            }
            else
            {
                this.Root.Append(newNode);
            }
        }

        // 重载，默认以根结点为起点插入  
        public void MidTravel()
        {
            this.MidTravel(this.Root);
        }

        // 中序遍历（递归）  
        public void MidTravel(Node node)
        {
            if (node.LeftSubNode != null)
            {
                this.MidTravel(node.LeftSubNode);
            }

            node.ShowData();

            if (node.RightSubNode != null)
            {
                this.MidTravel(node.RightSubNode);
            }
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Tree tree = new Tree();

            tree.Insert(new Node { Data = 3 });
            tree.Insert(new Node { Data = 6 });
            tree.Insert(new Node { Data = 2 });
            tree.Insert(new Node { Data = 7 });
            tree.Insert(new Node { Data = 18 });
            tree.Insert(new Node { Data = 1 });
            tree.Insert(new Node { Data = 2 });
            tree.MidTravel();
        }
    }