数据结构:二叉树的建立和遍历(C#实现)

遍历只做了先序,递归实现的,中序和后序都类似.代码比较简单,就不写注释,直接贴出来了

 

代码:

TreeNode:结点类

 

1. using System;
2. using System.Collections.Generic;
3. using System.Text;
5. namespace 二叉树的建立和遍历
6. {
7.     class TreeNode
8.     {
9.         public char data;
10.         public  TreeNode left, right;
11.         
12.         public TreeNode(char c,TreeNode l,TreeNode r)
13.         {
14.             data = c;
15.             left = l;
16.             right = r;
17.         }
18.         public TreeNode() { left = right = null; }
19.     }
20. }

 

 

Tree:树类

 

1. using System;
2. using System.Collections.Generic;
3. using System.Text;
5. namespace 二叉树的建立和遍历
6. {
7.     class Tree
8.     {
9.         public TreeNode root;
11.         Stack<TreeNode> stack = new Stack<TreeNode>();
12.         
13.         public void CreateTree(String description)
14.         {
15.             bool left=true; 
17.             char[] descriptionarray = description.ToCharArray();
19.             
21.             root = new TreeNode();
22.             root.data = descriptionarray[0];
24.             TreeNode temp=root;
25.            
27.             for (int i = 1; i <=descriptionarray.Length-1; i++)
28.             {
29.                 
31.                 if (descriptionarray[i] == '(')
32.                 {
33.                     left = true; stack.Push(temp);
34.                 }
36.                 else if (descriptionarray[i] == ',')
37.                 {
38.                     left = false;
39.                 }
41.                 else if (descriptionarray[i] == ')') { stack.Pop(); }
43.                 else
44.                 {
45.                     temp = new TreeNode();
46.                     temp.data = descriptionarray[i];
47.                     if (left == true)
48.                     {
49.                         stack.Peek().left = temp;
50.                     }
51.                     else
52.                     {
53.                         stack.Peek().right = temp;
54.                     }
55.                 }
57.                 
58.             }
59.         }
61.         
62.         public void PreOrder(TreeNode t,String sign)
63.         {
64.             
65.             if (t!= null)
66.             {
67.                 Console.WriteLine(sign+t.data);
69.                 sign += sign;
71.                 if (t.left != null)
72.                 {
73.                     
74.                     PreOrder(t.left,sign);
75.                 }
76.                 if (t.right != null)
77.                 {
78.                     
79.                     PreOrder(t.right,sign); 
80.                 }
81.             }
82.         }
85.     }
86. }

 

 

Program:调用者

 

1. using System;
2. using System.Collections.Generic;
3. using System.Text;
5. namespace 二叉树的建立和遍历
6. {
7.     class Program
8.     {
9.         static void Main(string[] args)
10.         {
11.             //TreeNode t=null;
12.             Tree tree = new Tree();
13.             Console.WriteLine("请输入用字符串表示的二叉树");
14.             string input =Console.ReadLine();
15.             tree.CreateTree(input);
16.             Console.WriteLine("遍历");
17.             tree.PreOrder(tree.root,"--");
18.             Console.Read();
19.         }
20.     }
21. }