Get Count of value in Binary Tree

BinaryTreeCount.java

/*
Interview Question:
Here's a binary tree: write a function to return the count of a certain value in the tree
*/
 
public class TreeNode{
  int data;
  TreeNode left;
  TreeNode right;
  
  public TreeNode(int d){
      data = d;
      left = null;
      right = null;
  }
}

public class IntWrapper{
  int value = 0;
}
 
public class BinaryTree{
  
 TreeNode root;
 
 public BinaryTree(){
  root = null;
 }
 
 public int getCountOfValue(int valueToCount){
   //Here is the IntWrapper we will use to simulate pass-by-reference
   IntWrapper count = new IntWrapper();
   
   //Assume the tree has been built already, not shown in the code here
   getCountOfValueHelper(root, valueToCount, count);
   
   return count.value;
 }
 
 public void getCountOfValueHelper(TreeNode node, int valueToCount, IntWrapper count){
   //Base case
   if (node == null){
     return;
   }
   
   //In Order traversal
   getCountOfValueHelper(node.left, valueToCount, count);
   
   if (node.data == valueToCount){
     //Update the count if value is found in current node
     count.value = count.value + 1;
   }
   
   getCountOfValueHelper(node.right, valueToCount, count);
 }
 
}