binarytreenode.java

源程序（包括最初的版本

/** 二叉树结点类 */

package datastructures;

public class BinaryTreeNode
{
   // datastructures包内可见的数据成员
   protected Object element;
   protected BinaryTreeNode leftChild;    // 对左子树的引用
   protected BinaryTreeNode rightChild;   // 对右子树的引用

   // 三个重载的构造方法
   public BinaryTreeNode() {}

   public BinaryTreeNode(Object theElement)
      {element = theElement;}

   public BinaryTreeNode(Object theElement,
                         BinaryTreeNode theleftChild,
                         BinaryTreeNode therightChild)
   {
       element = theElement;
       leftChild = theleftChild;
       rightChild = therightChild;
   }

   // 访问性方法
   public BinaryTreeNode getLeftChild() {return leftChild;}
   public BinaryTreeNode getRightChild() {return rightChild;}
   public Object getElement() {return element;}

   // 针对数据成员的变异性方法
   public void setLeftChild(BinaryTreeNode theLeftChild)
      {leftChild = theLeftChild;}
   public void setRightChild(BinaryTreeNode theRightChild)
      {rightChild = theRightChild;}
   public void setElement(Object theElement)
      {element = theElement;}

   // 输出数据元素方法
   public String toString()
     {return element.toString();}
}