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);
     }
 }