简单二叉树

花了10分钟写了下简单二叉树的三种遍历方法

package com.test;

import java.util.Random;

public class BinTreeTest {
	Node root;

	class Node {
		Node left;
		Node right;
		int data;

		public Node(int data) {
			this.data = data;
		}
	}

	public void createTree(Node node, int data) {
		if (node == null) {
			root = new Node(data);
		} else if (data > node.data) {
			if (node.left == null) {
				node.left = new Node(data);
			} else {
				createTree(node.left, data);
			}
		} else {
			if (node.right == null) {
				node.right = new Node(data);
			} else {
				createTree(node.right, data);
			}
		}
	}

	/**
	 * 前序遍历：先遍历根结点，然后遍历左子树，最后遍历右子树。
	 * 
	 * @param node
	 */
	public void prePrint(Node node) {
		if (node != null) {
			System.out.print(node.data + ",");
			prePrint(node.left);
			prePrint(node.right);
		}
	}

	/**
	 * 中序遍历：先遍历左子树，然后遍历根结点，最后遍历右子树。
	 */
	public void inPrint(Node node) {
		if (node != null) {
			prePrint(node.left);
			System.out.print(node.data + ",");
			prePrint(node.right);
		}
	}

	/**
	 * 后序遍历：先遍历左子树，然后遍历右子树，最后遍历根节点
	 * 
	 * @param node
	 */
	public void postPrint(Node node) {
		if (node != null) {
			prePrint(node.left);
			prePrint(node.right);
			System.out.print(node.data + ",");
		}
	}

	public static void main(String[] args) {
		BinTreeTest test = new BinTreeTest();
		Random r = new Random();
		for (int i = 0; i < 10; i++) {
			int data = r.nextInt(100);
			test.createTree(test.root, data);
		}
		test.prePrint(test.root);
		System.out.println("");
		test.inPrint(test.root);
		System.out.println("");
		test.postPrint(test.root);
	}
}