二叉树的遍历,递归版-先序中序后序

package com.algorithm.practice.tree.traversal;

public class PreInPosTraversal {
    public static class Node {
        public int value;
        public Node left;
        public Node right;

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

    public static void preOrderRecur(Node head) {
        if (head == null) {
            return;
        }
        System.out.print(head.value+" ");
        preOrderRecur(head.left);
        preOrderRecur(head.right);
    }
    public static void inOrderRecur(Node head) {
        if (head == null) {
            return;
        }
        inOrderRecur(head.left);
        System.out.print(head.value + " ");
        inOrderRecur(head.right);
    }

    public static void posOrderRecur(Node head) {
        if (head == null) {
            return;
        }
        posOrderRecur(head.left);
        posOrderRecur(head.right);
        System.out.print(head.value + " ");
    }

    public static void main(String[] args){
        Node head = new Node(5);
        head.left = new Node(3);
        head.right = new Node(8);
        head.left.left = new Node(2);
        head.left.right = new Node(4);
        head.left.left.left = new Node(1);
        head.right.left = new Node(7);
        head.right.left.left = new Node(6);
        head.right.right = new Node(10);
        head.right.right.left = new Node(9);
        head.right.right.right = new Node(11);
        preOrderRecur(head);
        System.out.println();
        inOrderRecur(head);
        System.out.println();
        posOrderRecur(head);
    }


}