二叉树

代码实现：

package cn.demo;

class Phone implements Comparable <Phone> {
    private String brand ;
    private double price ;
    public Phone(String brand,double price) {
        this.brand = brand ;
        this.price = price ;
    }
    @Override
    public String toString() {
        return "品牌：" + this.brand + "，价格：" + this.price + "\n" ;
    }
    @Override
    public int compareTo(Phone o) {
        if (this.price > o.price) {
            return 1 ;
        } else if (this.price < o.price) {
            return -1 ; 
        } else {
            return 0 ;
        }
    }
}
class BinaryTree {
    // 不管是什么数据结构一定要求有Node类
    private class Node {
        @SuppressWarnings("rawtypes")
        private Comparable data ;
        private Node left ;
        private Node right ;
        @SuppressWarnings("rawtypes")
        public Node(Comparable data) {
            this.data = data ;
        } 
        public void addNode(Node newNode) {
            if (newNode.data.compareTo(this.data) < 0) {
                if (this.left == null) {    // 现在左边没有数据
                    this.left = newNode ;
                } else {
                    this.left.addNode(newNode);
                }
            } else {
                if (this.right == null) {
                    this.right = newNode ;
                } else {
                    this.right.addNode(newNode);
                }
            }
        }
        public void toArrayNode() {
            if (this.left != null) {
                this.left.toArrayNode(); 
            }
            BinaryTree.this.retObj [BinaryTree.this.foot ++] = this.data ;
            if (this.right != null) {
                this.right.toArrayNode(); 
            }
        }
    }
    // 编写BinaryTree中的程序代码，任何的节点操作离不开根节点
    private Node root ;    // 定义根节点，第一个保存的数据作为根节点
    private int count ;
    private int foot ;
    private Object retObj [] ;    // 设置返回的数据
    public void add(Object obj) {
        if (obj == null) {
            return ;
        }
        Node newNode = new Node((Comparable) obj) ;
        if (this.root == null) {    // 现在没有根节点
            this.root = newNode ;
        } else {    // 如果有根节点，需要判断其保存的位置
            this.root.addNode(newNode) ;
        }
        this.count ++ ;
    }
    public int size() {
        return this.count ;
    }
    public Object [] toArray() {
        if (this.count == 0) {
            return null ;
        }
        this.retObj = new Object [this.count] ;
        this.foot = 0 ;
        this.root.toArrayNode() ;
        return this.retObj ;
    }
}

public class Test {
    public static void main(String[] args) {
        BinaryTree bt = new BinaryTree() ;
        bt.add(new Phone("黑米",799.00));
        bt.add(new Phone("白米",399.00));
        bt.add(new Phone("紫米",899.00));
        System.out.println(bt.size());
        Object obj [] = bt.toArray() ;
        for (int x = 0 ; x < obj.length ; x ++) {
            System.out.println(obj[x]);
        }
    }
}

输出结果：

3
品牌：白米，价格：399.0

品牌：黑米，价格：799.0

品牌：紫米，价格：899.0