/*题目：用java语言创建二叉树，完成二叉树的建立和遍历;*/import java.util.Scanner;class  BinaryTreeDemo{	public static void main(String[] args) 	{		Node binaryNode = new Node();		BinaryTree binaryTree = new BinaryTree(binaryNode);		System.out.println("创建二叉树：");		binaryNode = binaryTree.createBinaryTree();		System.out.println("前序遍历：");		binaryTree.PreTree(binaryNode);		System.out.println();		System.out.println("中序遍历");		binaryTree.InOrderTree(binaryNode);		System.out.println();		System.out.println("后序遍历");		binaryTree.PostOrderTree(binaryNode);	}}/*二叉树特点：最多有两个节点*/class Node{	// 存储二叉树节点值	public int data;	// 左节点	public Node leftChild;	// 右节点	public Node rightChild;}class BinaryTree{	//创建一个父节点	private Node rootNode;	public BinaryTree(Node rootNode)	{		this.rootNode = rootNode;	}	//  按前序建立二叉树	public Node createBinaryTree()	{		Node temp = new Node();		Scanner sc = new Scanner(System.in);		int value = sc.nextInt();		if(value == 0)		//输入0表示该节点为空		{			temp = null;		}		else		{			temp.data = value;			temp.leftChild = createBinaryTree();			temp.rightChild = createBinaryTree();		}		return temp;	}	//  前序遍历	public void PreTree(Node t)	{		if(t == null)			return;		System.out.print(t.data + " ");		PreTree(t.leftChild);		PreTree(t.rightChild);	}	//  中序遍历	public void InOrderTree(Node t)	{		if(t == null)			return;		InOrderTree(t.leftChild);		System.out.print(t.data + " ");		InOrderTree(t.rightChild);	}	//  后序遍历	public void PostOrderTree(Node t)	{		if(t == null)			return;		PostOrderTree(t.leftChild);		PostOrderTree(t.rightChild);		System.out.print(t.data + " ");	}}