二叉树的遍历

public class TreeTest {
	
	
	static class TreeNode{
		public String data;//数据
		public TreeNode lChild;//左孩子
		public TreeNode rChild;//右孩子
	};

	/**
	 * @Title: main
	 * @Description: TODO(这里用一句话描述这个方法的作用)
	 * @param @param args    设定文件
	 * @return void    返回类型
	 * @throws 
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		TreeNode root = new TreeNode();
		root.data = "0";
		createTree(root);
		System.out.println("前根遍历");
		preOrder(root);
		System.out.println("中根遍历");
		midOrder(root);
		System.out.println("后根遍历");
		LatOrder(root);
	}
	
	
	public static void createTree(TreeNode node) {
		String data = node.data;
		if(data.length()<=2){
//			System.out.println("createing!!");
			TreeNode lNode = new TreeNode();
			node.lChild = lNode;
			lNode.data = data+"1";
			createTree(lNode);
			
			
			TreeNode rNode = new TreeNode();
			node.rChild = rNode;
			rNode.data = data+"2";
			createTree(rNode);
		}
	}
	
	//前根遍历
	public static void preOrder(TreeNode node){
		if(null != node){
			System.out.println(node.data);
			preOrder(node.lChild);
			preOrder(node.rChild);
		}
	}
	
	//中根遍历
	public static void midOrder(TreeNode node){
		if(null != node) {
			midOrder(node.lChild);
			System.out.println(node.data);
			midOrder(node.rChild);
		}
	} 
	
	//后根遍历
	public static void LatOrder(TreeNode node){
		if(null != node) {
			LatOrder(node.lChild);
			LatOrder(node.rChild);
			System.out.println(node.data);
		}
	}
	

}