package Binary_Tree_Three_Traversal;/** * 二叉树三种递归遍历 * @author 1 **/public class Node {public Node left; // 左子结点    public Node right; // 右子结点    public int value; // 结点值

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

public Node() {    }

// 前序遍历    public static void preTraversal(Node node) {if (node != null) {            System.out.print(node.value+" "); //输出当前结点值        }if (node.left != null) {            preTraversal(node.left); //读左结点        }if (node.right != null) {            preTraversal(node.right); // 读右结点        }    }

// 中序遍历    public static void midTraversal(Node node){if(node.left != null){            midTraversal(node.left);        }if(node != null){            System.out.print(node.value+" ");        }if(node.right != null){            midTraversal(node.right);        }    }

// 后序遍历    public static void behTraversal(Node node){if(node.left != null){            behTraversal(node.left);        }if(node != null){            System.out.print(node.value+" ");        }if(node.right != null){            behTraversal(node.right);        }    }public static void main(String[] args) {// 初始化5个结点,值分别为: 1,2,3,4,5        Node n1 = new Node(1);        Node n2 = new Node(2);        Node n3 = new Node(3);        Node n4 = new Node(4);        Node n5 = new Node(5);        Node n6 = new Node(); // 值默认为0        Node n7 = null;

        System.out.println("n6 = "+n6);         System.out.println("n7 = "+n7); // null

// 构建二叉树, 以n1为根结点        n1.left = n2;        n1.right = n5;        n2.left = n3;        n2.right = n4;        n5.left = n6;        n5.right = n7;

        System.out.print("前序遍历结果为: ");        preTraversal(n1);         System.out.println();        System.out.print("中序遍历结果为: ");        midTraversal(n1);        System.out.println();        System.out.print("后序遍历结果为: ");        behTraversal(n1);    }}