>>>>See comment in line. I don't understand that syntax.
>>>
>>>The TTreeNode class has left and right pointers of the same class.
>>
>>Hi,
>>

public TTreeNode left, right;

is just a shortcut for :
>>

 public TTreeNode left;
>>public TTreeNode right;

i.e. just declaring two TTreeNode objects....
>>HTH,
>>Viv
>
>Yes, I know, hopefully it's clearer for Kevin too now.

Oops. Meant to reply to Kevin. Sorry.
Best,
Viv