二叉树是学习数据结构与算法的重要内容，现做综合操作二叉树的汇总。由于关于这方面的文章、书籍已是随处可见，故此间的细节不再赘述，附上一段代码，并提供实例，供参考。代码已测试没有问题。
public class Node // 定义二叉树节点类 Node
{
public int Data;
public Node Left;
public Node Right;
public void Display()
{
Console.WriteLine(Data);
}
public Node(int x)
{
Data = x;
}
}
public class BinaryTree // 定义二叉树
{
public Node Current; //
Node Parent; // 定义一个 Parent，用于存储当前节点（Current）的父节点，为添加删除节点方法做准备
public Node Root; // 定义根结点
public BinaryTree() // 构造函数，初始化二叉树
{
Root = null;
}
public void InOrder(Node theRoot) // 通过递归，中序遍历
{
if (theRoot != null)
{
InOrder(theRoot.Left);
Console.Write(theRoot.Data + "\t");
InOrder(theRoot.Right);
}
}
public void PreOrder(Node theRoot) // 通过递归，先序遍历
{
if (theRoot != null)
{
Console.Write(theRoot.Data + "\t");
PreOrder(theRoot.Left);
PreOrder(theRoot.Right);
}
}
public void PostOrder(Node theRoot) // 通过递归，后序遍历
{
if (theRoot != null)
{
PostOrder(theRoot.Left);
PostOrder(theRoot.Right);
Console.Write(theRoot.Data+"\t");
}
}
public void Insert(int x) // 插入节点
{
Node newNode = new Node(x);
Current = Root;
if (Root == null)
{
Root = newNode;
}
else
{
while (true)
{
Parent = Current;
if (x < Current.Data)
{
Current = Current.Left;
if (Current == null)
{
Parent.Left = newNode;
break;
}
}
else
{
Current = Current.Right;
if (Current == null)
{
Parent.Right = newNode;
break;
}
}
}
}
}
public int Min() // 查找最小值
{
Current = Root;
while (Current.Left != null)
Current = Current.Left;
return Current.Data;
}
public int Max() // 查找最大值
{
Current = Root;
while (Current.Right != null)
Current = Current.Right;
return Current.Data;
}
public Node Find(int key) // 查找某一个确定的节点的值
{
Current = Root;
while (Current != null)
{
if (key == Current.Data)
break; // 找到了就结束 while 循环
if (key < Current.Data)
{
Parent = Current;
Current = Current.Left;
}
else
{
Parent = Current;
Current = Current.Right;
}
}
if (Current == null)
return null;
else
return Current;
}
}
class Program
{
static void Main(string[] args)
{
BinaryTree bst = new BinaryTree();
bst.Insert(25);
bst.Insert(50);
bst.Insert(15);
bst.Insert(33);
bst.Insert(4);
bst.Insert(100);
bst.Insert(20);
bst.Insert(38);
bst.Insert(1);
bst.Insert(10);
bst.Insert(18);
bst.Insert(30);
bst.Insert(32);
Console.WriteLine("The min is: {0}", bst.Min());
Console.WriteLine("The max is: {0}", bst.Max());
Console.Write("Find \"100\": ");
Console.Write(bst.Find(100).Data+"\n");
Console.WriteLine("\n" + "PreOrder: ");
bst.PreOrder(bst.Root);
Console.WriteLine("\n" +"PostOrder:");
bst.PostOrder(bst.Root);
Console.WriteLine("\n"+"InOrder: ");
bst.InOrder(bst.Root);
Console.Read();
}
}运行结果：
The min is: 1
The max is: 100
Find “100”: 100
PreOrder:
25 15 4 1 10 20 18 50 33 30 32 38 100
PostOrder:
1 10 4 18 20 15 32 30 38 33 100 50 25
InOrder:
1 4 10 15 18 20 25 30 32 33 38 50 100
