二叉樹的展示功能（中序遍歷）

	private void show(Node node) {
		if (node != null) {
			this.show(node.leftChildNode);
			System.out.println(node.key + ":" + node.value);
			this.show(node.rightChildNode);

		}
	}

public static void main(String[] args) {
		Node root = new Node(50, 24);
		Tree tree = new Tree(root);
		tree.insert(20, 530);
		tree.insert(540, 520);
		tree.insert(4, 540);
		tree.insert(0, 550);
		tree.insert(8, 520);
		tree.show();
	}
 

package tree;

/**
 * 二叉樹
 * 
 * @author JYC506
 * 
 */
public class Tree {
	/**
	 * 跟節點
	 */
	private Node root;

	/**
	 * 構造方法
	 */
	public Tree() {

	}

	/**
	 * 構造方法
	 * 
	 * @param root
	 *            跟節點
	 */
	public Tree(Node root) {
		this.root = root;
	}

	/**
	 * 查詢節點
	 * 
	 * @param key
	 * @return
	 */
	public Node find(int key) {
		if (this.root != null) {
			Node currentNode = this.root;
			while (currentNode.key != key) {
				if (key > currentNode.key) {
					currentNode = currentNode.rightChildNode;
				} else {
					currentNode = currentNode.leftChildNode;
				}
				if (currentNode == null) {
					return null;
				}
			}
		}
		return null;
	}

	/**
	 * 插入節點
	 * 
	 * @param key
	 *            key
	 * @param value
	 *            值
	 */
	public void insert(int key, Object value) {
		Node node = new Node(key, value);
		if (this.root == null) {
			this.root = node;
		} else {
			Node currentNode = this.root;
			while (true) {
				if (key > currentNode.key) {
					if (currentNode.rightChildNode == null) {
						currentNode.rightChildNode = node;
						return;
					} else {
						currentNode = currentNode.rightChildNode;
					}
				} else {
					if (currentNode.leftChildNode == null) {
						currentNode.leftChildNode = node;
						return;
					} else {
						currentNode = currentNode.leftChildNode;
					}
				}
			}
		}

	}

	/**
	 * 展示
	 */

	public void show() {
		this.show(root);
	}

	/**
	 * 中序遍歷
	 * 
	 * @param node
	 */
	private void show(Node node) {
		if (node != null) {
			this.show(node.leftChildNode);
			System.out.println(node.key + ":" + node.value);
			this.show(node.rightChildNode);

		}
	}

	public static void main(String[] args) {
		Node root = new Node(50, 24);
		Tree tree = new Tree(root);
		tree.insert(20, 530);
		tree.insert(540, 520);
		tree.insert(4, 540);
		tree.insert(0, 550);
		tree.insert(8, 520);
		tree.show();
	}
}

class Node {
	/* key */
	int key;
	/* 值 */
	Object value;
	/* 左節點 */
	Node leftChildNode;
	/* 右節點 */
	Node rightChildNode;

	/**
	 * 構造方法
	 * 
	 * @param key
	 *            關鍵字
	 * @param value
	 *            值
	 */
	public Node(int key, Object value) {
		super();
		this.key = key;
		this.value = value;
	}

}