二叉树的java算法

package com.wu; import java.util.Scanner; class DoubleLinkedList { private DoubleLinkedListNode head; private DoubleLinkedListNode mark; private int length; public int getLength() { return length; } void create(){ Scanner in = new Scanner(System.in); head = new DoubleLinkedListNode(in.nextInt()); ++length; mark = head; int data; while((data = in.nextInt()) != -1){ DoubleLinkedListNode q = new DoubleLinkedListNode(data); head.setRight(q); q.setLeft(head); head = q; ++length; } in.close(); } void print(){ //DoubleLinkedListNode p = head; while(mark.getRight() != null) { System.out.print(mark.getData() + " "); mark = mark.getRight(); } System.out.print(mark.getData()); } }