我正在尝试添加到字符串的BST中,但似乎无法正确订购它们

所以基本上我正在尝试制作看起来像这样的树                                   铝                                  / \                                鲍勃·卡罗尔                               / \                          黛比·伊莱恩

我相信我现在订购的方式是

                      Al
                        \
                         Bob
                           \
                            Carol
                              \ 
                             Debby
                                 \
                                Elaine

这是我有atm的代码

BNode root;
  public lab6M(){
    root = null;
  }

  public boolean add(String s){
    root = add(s, root);
    return true;
  }
  private BNode add(String s, BNode b){
    if(b == null)
      b = new BNode(s);
    else if(b.value.compareTo(s) == 0)
      return b;
    else if(b.value.compareTo(s) > 0)
      b.left = add(s, b.left);
    else
      b.right = add(s, b.right);
    return b;
  }