public BinaryTree()
 {
     this.root = new LLNode(0);
 }
 public void SetRight(LLNode right)
 {
     this.right = right;
 }
 public LLNode(int data)
 {
     this.data  = data;
     this.left  = null;
     this.right = null;
 }
 public void SetLeft(LLNode left)
 {
     this.left = left;
 }
 //constructors
 public LLNode(int data, LLNode left, LLNode right)
 {
     this.left  = left;
     this.right = right;
     this.data  = data;
 }