C#实现二叉树外带中序遍历

using System;

namespace BinaryTree

{

    // 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/向右追加结点，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);

        }

    }

    // BinaryTree类

    class Tree

    {

        // 根结点

        public Node Root { get; set; }

        // 以根结点为起点，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遍历

        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.MidTravel();

        }

    }

}