二叉树遍历 ，前序，中序，后序， 递归版本

Java实现。

package bigo;class Node{    int data;    Node left;    Node right;    Node(int x) { data = x;}}public class midOrder {    public static void midOrder(Node root){        if (root != null){            midOrder(root.left);            System.out.println(root.data);            midOrder(root.right);        }    }    public static void preOrder(Node root){        if (root != null){            System.out.println(root.data);            preOrder(root.left);            preOrder(root.right);        }    }    public static void afterOrder(Node root){        if (root != null){            afterOrder(root.left);            afterOrder(root.right);            System.out.println(root.data);        }    }    public static void main(String [] arg){    /*  创建以下的树            10          /   \        8      2      /  \    /    3     5  2    */        Node root = new Node(10);        root.left = new Node(8);        root.right = new Node(2);        root.left.left = new Node(3);        root.left.right = new Node(5);        root.right.left = new Node(2);        System.out.println("中序：");        midOrder(root);        System.out.println("前序：");        preOrder(root);        System.out.println("后序：");        afterOrder(root);    }}

结果

中序：3851022前序：1083522后序：3582210