用递归方式实现二叉树先序、中序、后序遍历

先序遍历：中、左、右

中序遍历：左、中、右

后序遍历：左、右、中

 

比如下面这科树

             1

        2       3

    4    5   6    7

 

package com.sangfor.tree;


public class Node {
	public int value;
	public Node left;
	public Node right;
	public Node(int value) {
		this.value = value;
	}
}

 

package com.sangfor.tree;

public class ForEachTree {
    public static void main(String[] args) {
    	Node node1 = new Node(1);
    	Node node2 = new Node(2);
    	Node node3 = new Node(3);
    	Node node4 = new Node(4);
    	Node nod