二叉樹（簡單版）

 樹是一種非線性結構,樹的本質是將一些節點由邊鏈接起來，造成層級的結構，即1：N的關係，下面是手動構建數據之間的關係：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Tree3
{
    //手動構建節點之間的關係
    public class Program
    {
        static void Main(string[] args)
        {
          
            Node<string> rootNode =BinTree();
          
            Console.WriteLine("先序遍歷方法遍歷二叉樹： ");
            PreOrde(rootNode);

            Console.WriteLine("");
            Console.WriteLine("");
            Console.WriteLine("中序遍歷方法遍歷二叉樹：");
            InOrde(rootNode);

            Console.WriteLine("");
            Console.WriteLine("");
            Console.WriteLine("後序遍歷方法遍歷二叉樹：");
            AfterOrde(rootNode);
            Console.ReadKey();
        }
        /// <summary>
        /// 構建二叉樹
        /// </summary>
        /// <returns></returns>
        public static Node<string> BinTree()
        {
            Node<string>[] binTree = new Node<string>[11];
            //建立節點
            binTree[0] = new Node<string>("A");
            binTree[1] = new Node<string>("B");
            binTree[2] = new Node<string>("C");
            binTree[3] = new Node<string>("D");
            binTree[4] = new Node<string>("E");
            binTree[5] = new Node<string>("F");
            binTree[6] = new Node<string>("G");
            binTree[7] = new Node<string>("H");
            binTree[8] = new Node<string>("J");
            binTree[9] = new Node<string>("K");
            binTree[10] = new Node<string>("L");

            //構建關係
            binTree[0].LNode = binTree[1];
            binTree[0].RNode = binTree[2];
            binTree[1].LNode = binTree[3];
            binTree[1].RNode = binTree[4];
            binTree[2].LNode = binTree[6];
            binTree[2].RNode = binTree[7];
            binTree[6].RNode = binTree[8];
            binTree[7].RNode = binTree[9];
            binTree[8].RNode = binTree[10];

            //返回跟節點
            return binTree[0];
        }

        /// <summary>
        /// 先序遍歷（先訪問跟節點->在訪問左孩子->在訪問右孩子）遞歸 
        /// 注意的是：遍歷左右子樹時仍然採用中序遍歷方法。
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="rootNode"></param>
        public static void PreOrde<T>(Node<T> rootNode)
        {
            if (rootNode != null)
            {
                Console.Write(string.Format("{0} ", rootNode.Data));
                PreOrde(rootNode.LNode);
                PreOrde(rootNode.RNode);
            }
        }
        /// <summary>
        /// 中序遍歷（先訪問左節點->在訪問跟節點->在訪問右孩子）遞歸
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="rootNode"></param>
        public static void InOrde<T>(Node<T> rootNode)
        {
            if (rootNode != null)
            {
                InOrde(rootNode.LNode);
                Console.Write(string.Format("{0} ", rootNode.Data));
                InOrde(rootNode.RNode);
            }
        }
        /// <summary>
        /// 後序遍歷（先訪問左節點->在訪問右節點->在訪問跟孩子）遞歸
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="rootNode"></param>
        public static void AfterOrde<T>(Node<T> rootNode)
        {
            if (rootNode != null)
            {
                AfterOrde(rootNode.LNode);
                AfterOrde(rootNode.RNode);
                Console.Write(string.Format("{0} ", rootNode.Data));
            }
        }  
    }
    //節點類
    public class Node<T>
    {
     
        private T data;
        /// <summary>
        /// 數據
        /// </summary>
        public T Data
        {
            get { return data; }
            set { data = value; } 
        }

        private Node<T> lnode;
        /// <summary>
        /// 左孩子
        /// </summary>
        public Node<T> LNode
        {
            get { return lnode; }
            set { lnode = value; } 
        }
          
        private Node<T> rnode;
        /// <summary>
        /// 右孩子
        /// </summary>
        public Node<T> RNode { 
            get { return rnode; }
            set { rnode = value; }
             }

        /// <summary>
        /// 無參構造函數
        /// </summary>
        public  Node()
        {

        }
        /// <summary>
        /// 節點構造函數
        /// </summary>
        /// <param name="data"></param>
        public  Node(T data)
        {
            this.data = data;
        }
       

    }
}

運行結果：