二叉树的实现

/// <summary>
    /// 二叉树的应用
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public class Node<T>
    {
        public T m_Item;
        public Node<T> m_LeftNode;
        public Node<T> m_RightNode;
        public Node(T item,Node<T> leftNode,Node<T> rightNode)
        {
            this.m_Item = item;
            this.m_LeftNode = leftNode;
            this.m_RightNode = rightNode;
        }

    }
    public class Tree<T>
    {
        Node<T> root;
        public Tree(Node<T> root)
        {
            this.root = root;
        }
        public IEnumerable<T> GetEnum
        {
            get
            {
                return DisplayTree(root);
            }
        }
        public IEnumerable<T> DisplayTree(Node<T> root)
        {
            //遍历左子树
            if (root.m_LeftNode != null)
                foreach (T item in DisplayTree(root.m_LeftNode))
                    yield return item;
            //遍历根节点
            yield return root.m_Item;
            //遍历右子树
            if (root.m_RightNode != null)
                foreach (T item in DisplayTree(root.m_RightNode))
                    yield return item;
        }
    }
    public class CreateTree
    {
        public Tree<string> tree;
        public CreateTree()
        {
            tree = new Tree<string>(new Node<string>("A",
                  new Node<string>("B", null, null),
                  new Node<string>("C",
                    new Node<string>("D", null, null),
                    new Node<string>("E", null, null))));

        }
        public  void Display()
        {
           
            foreach (string s in tree.GetEnum)
                Console.WriteLine(s);
        }

    }