java数据结构之二叉树的实现

java二叉树的简单实现，可以简单实现深度为n的二叉树的建立，二叉树的前序遍历，中序遍历，后序遍历输出。

/**
 *数据结构之树的实现
 *2016/4/29
 *
 **/
package cn.Link;

public class Tree {
    Node head = new Node();
    Tree(){} 

    //内部节点类
    class Node{
        String date;
        Node left;
        Node right;
        Node(){ }
        Node(String date){
            this.date = date;
            this.left = null;
            this.right = null;
        }
    }

    //给深度为n的满二叉树添加数据  n表示数的深度
    public void addTree(Node preNode,int n){
        if(n ==1) return;
        preNode.date = "sum"+n;
        Node preNodeLeft = new Node();
        Node preNodeRight = new Node();
        
        preNode.left = preNodeLeft;
        addTree(preNodeLeft,n-1);
        preNode.right = preNodeRight;
        addTree(preNodeRight,n-1);
    }

    //前序遍历二叉树  并输出
    public void printTreePre(Node preNode){
        if(preNode == null) return;
        if(preNode.left!=null || preNode.right!=null)
        System.out.print(preNode.date+"  ");

        printTreePre(preNode.left);
        printTreePre(preNode.right);
    }   
    
    //中序遍历二叉树  并输出
    public void printTreeAmong(Node preNode){
        if(preNode == null) return;
        printTreeAmong(preNode.left);
        if(preNode.left!=null || preNode.right!=null)
        System.out.print(preNode.date+"  ");
        printTreeAmong(preNode.right);
    }   

    //后序遍历二叉树  并输出
    public void printTreeRear(Node preNode){
        if(preNode == null) return;
        printTreeRear(preNode.left);
        printTreeRear(preNode.right);

        if(preNode.left!=null || preNode.right!=null)
        System.out.print(preNode.date+"  ");
    }   


    //测试函数
    public static void main(String [] args){
    Tree tree = new Tree();
    tree.addTree(tree.head,4);
    System.out.println("================前序遍历================");
    tree.printTreePre(tree.head);
    System.out.println();
    System.out.println("================中序遍历===============");
    tree.printTreeAmong(tree.head);
    System.out.println();
    System.out.println("================后序遍历===============");
    tree.printTreeRear(tree.head);
    System.out.println();
    System.out.println("============手工输出所有数据===========");
    System.out.println(tree.head.date);
    System.out.println(tree.head.left.date+" "+tree.head.right.date);
    System.out.println(tree.head.left.left.date+"  "+tree.head.left.right.date+"   "+tree.head.right.left.date+"   "+tree.head.right.right.date);
    }
}