二叉树的创建和三种遍历方式

public class BinaryTree {

public static void main(String[] args)

{

int[] arr = {2,4,6,8,22,34,77,44};

BinaryTree bt = new BinaryTree();

for(int i=0;i<arr.length;i++)

{

bt.buildTree(bt.root, arr[i]);

}

bt.preOrder(bt.root);

bt.inOrder(bt.root);

bt.postOrder(bt.root);

}

private static Node root;

private class Node{

private Node left;

private Node right;

private int data;

public Node(int data)

{

this.data = data;

}

}

public BinaryTree()

{

this.root = null;

}

public static void buildTree(Node node,int data)

{

if(root==null)

{

root = new Node(data);

}

else

{

if(data<node.data)

{

if(node.left==null)

node.left = new Node(data);

else

buildTree(node.left,data);

}

else if(data>node.data)

{

if(node.right==null)

node.right = new Node(data);

else

buildTree(node.right,data);

}

}

}

public static void preOrder(Node node)//前序遍历

{

if(node!=null)

{

System.out.println(node.data);

preOrder(node.left);

preOrder(node.right);

}

}

public static void inOrder(Node node)//中序遍历

{

if(node!=null)

{

inOrder(node.left);

System.out.println(node.data);

inOrder(node.right);

}

}

public static void postOrder(Node node)//后序遍历

{

if(node!=null)

{

postOrder(node.left);

postOrder(node.right);

System.out.println(node.data);

}

}

}