Java 在二叉树中计算叶子

我一直在试图弄清楚，当我从tester类调用countingLeaves方法时，为什么找不到它

我的编译器给了我一个错误TreeTester.java:25:error:找不到符号 数叶（）； ^ 符号：方法countLeaves（） 地点：TreeTester级

    public class BinarySearchTree
{  
   private Node root;


   public BinarySearchTree()
   {  
      root = null;
   }


   public void add(Comparable obj) 
   {  
      Node newNode = new Node();
      newNode.data = obj;
      newNode.left = null;
      newNode.right = null;
      if (root == null) { root = newNode; }
      else { root.addNode(newNode); }
   }


   public boolean find(Comparable obj)
   {
      Node current = root;
      while (current != null)
      {
         int d = current.data.compareTo(obj);
         if (d == 0) { return true; }
         else if (d > 0) { current = current.left; }
         else { current = current.right; }
      }
      return false;
   }


   public void remove(Comparable obj)
   {


      Node toBeRemoved = root;
      Node parent = null;
      boolean found = false;
      while (!found && toBeRemoved != null)
      {
         int d = toBeRemoved.data.compareTo(obj);
         if (d == 0) { found = true; }
         else 
         {
            parent = toBeRemoved;
            if (d > 0) { toBeRemoved = toBeRemoved.left; }
            else { toBeRemoved = toBeRemoved.right; }
         }
      }

      if (!found) { return; }



      if (toBeRemoved.left == null || toBeRemoved.right == null)
      {
         Node newChild;
         if (toBeRemoved.left == null) 
         {
            newChild = toBeRemoved.right;
         }
         else 
         {
            newChild = toBeRemoved.left;
         }

         if (parent == null) // Found in root
         {
            root = newChild;
         }
         else if (parent.left == toBeRemoved)
         {
            parent.left = newChild;
         }
         else 
         {
            parent.right = newChild;
         }
         return;
      }



      Node smallestParent = toBeRemoved;
      Node smallest = toBeRemoved.right;
      while (smallest.left != null)
      {
         smallestParent = smallest;
         smallest = smallest.left;
      }



      toBeRemoved.data = smallest.data;
      if (smallestParent == toBeRemoved) 
      {
         smallestParent.right = smallest.right; 
      }
      else 
      {
         smallestParent.left = smallest.right; 
      }
   }


   public void print()
   {  
      print(root);
      System.out.println();
   }  


   private static void print(Node parent)
   {  
      if (parent == null) { return; }
      print(parent.left);
      System.out.print(parent.data + " ");
      print(parent.right);
   }

   public int countLeaves(Node node)
   {

      if(node == null)
         return 0;
      else if(node.left == null && node.right == null)
      {
         return 1;
      }
      else
      {
         return countLeaves(node.left) + countLeaves(node.right);
      }
   }


   class Node
   {  
      public Comparable data;
      public Node left;
      public Node right;


      public void addNode(Node newNode)
      {  
         int comp = newNode.data.compareTo(data);
         if (comp < 0)
         {  
            if (left == null) { left = newNode; }
            else { left.addNode(newNode); }
         }
         else if (comp > 0)
         {  
            if (right == null) { right = newNode; }
            else { right.addNode(newNode); }
         }
      }
   }
}

---

countLeaves需要一个节点，而不是BinarySearchTree。

countLeaves需要一个

节点，而不是
BinarySearchTree

您可以在BinarySearchTree中添加如下方法：

Node getRoot(){return root;}

Amd使用
countLeaves（t.getRoot（））
编译器正在您的
TreeTester
类中查找方法
countLeaves（）
。。。但是它是在您的
二进制搜索树
类中定义的。因此，您需要调用
t.countLeaves（）
并将一个节点作为参数传递。也许可以改为在Er，t.countLeaves上问这个问题。我使用了t.countLeaves（getRoot（））；它仍然在我的treetester类中搜索。我相信我没有理解这个概念。@sippycup
t.countLeaves（t.getRoot（））
我得到了3的结果，所以我相信你已经解决了我的难题谢谢@不客气。你能给我一个最好的答案吗？
Node getRoot(){return root;}