<p>This may be a simple fix - but I'm trying to sum together all the nodes (Size property from the Node class) on the binary search tree. Below in my BST class I have the following so far, but it returns 0:</p>

<pre><code>    private long sum(Node&lt;T&gt; thisNode)
    {
        if (thisNode.Left == null &amp;&amp; thisNode.Right == null)
            return 0;
        if (node.Right == null)
            return sum(thisNode.Left);
        if (node.Left == null) 
            return sum(thisNode.Right);


        return sum(thisNode.Left) + sum(thisNode.Right);
    }
</code></pre>

<p>Within my Node class I have Data which stores Size and Name in their given properties. I'm just trying to sum the entire size. Any suggestions or ideas?</p>

Maybe you meant
```
```
if (thisNode.Left == null && thisNode.Right == null)
        return thisNode.Size;
```
```
?