遍历二叉树

package com.binarytree.test;

/**
 * 遍历二叉树
 * @author ncs
 *
 */
public class BinaryTree {

	public static void main(String[] args) {
		BinaryTree tree = new BinaryTree();
		TreeNode node = tree.createBinaryTree();
		// 先序遍历。。。。。。。
		System.out.println("**************************");
		System.out.println("先序遍历。。。。。。。");
		tree.xianIterator(node);
		System.out.println("");
		// 中序遍历。。。。。。。
		System.out.println("**************************");
		System.out.println("中序遍历。。。。。。。");
		tree.zhongIterator(node);
		System.out.println("");
		// 后续遍历。。。。。。。
		System.out.println("**************************");
		System.out.println("后序遍历。。。。。。。");
		tree.houIterator(node);
	}

	//创建二叉树
	public TreeNode createBinaryTree() {
		TreeNode D = new TreeNode("D", null, null);
		TreeNode B = new TreeNode("B", D, null);
		TreeNode E = new TreeNode("E", null, null);
		TreeNode F = new TreeNode("F", null, null);
		TreeNode C = new TreeNode("C", E, F);
		TreeNode A = new TreeNode("A", B, C);
		return A;
	}

	//先序遍历NLR N(Node）、L(Left subtree）和R(Right subtree）
	public void xianIterator(TreeNode node) {
		this.printNode(node);
		if (node.getLeftNode() != null) {
			this.xianIterator(node.getLeftNode());
		}
		if (node.getRightNode() != null) {
			this.xianIterator(node.getRightNode());
		}
	}

	//中序遍历LNR
	public void zhongIterator(TreeNode node) {
		if (node.getLeftNode() != null) {
			this.zhongIterator(node.getLeftNode());
		}
		this.printNode(node);
		if (node.getRightNode() != null) {
			this.zhongIterator(node.getRightNode());
		}
	}

	//后续遍历LRN
	public void houIterator(TreeNode node) {
		if (node.getLeftNode() != null) {
			this.houIterator(node.getLeftNode());
		}
		if (node.getRightNode() != null) {
			this.houIterator(node.getRightNode());
		}
		this.printNode(node);

	}
	
	public void printNode(TreeNode node) {
		System.out.print(node.getData());
	}
}

class TreeNode {
	private String data;
	private TreeNode leftNode;
	private TreeNode rightNode;
	public TreeNode(String data, TreeNode leftNode, TreeNode rightNode) {
		this.data = data;
		this.leftNode = leftNode;
		this.rightNode = rightNode;
	}

	public String getData() {
		return data;
	}

	public void setData(String data) {
		this.data = data;
	}

	public TreeNode getLeftNode() {
		return leftNode;
	}

	public void setLeftNode(TreeNode leftNode) {
		this.leftNode = leftNode;
	}

	public TreeNode getRightNode() {
		return rightNode;
	}

	public void setRightNode(TreeNode rightNode) {
		this.rightNode = rightNode;
	}
}