/// Add_internal - Creates a new tree that includes the specified
/// data and the data from the original tree. If the original tree
/// already contained the data item, the original tree is returned.
TreeTy* Add_internal(value_type_ref V, TreeTy* T) {
if (isEmpty(T))
return CreateNode(T, V, T);
/// Add_internal - Creates a new tree that includes the specified
/// data and the data from the original tree. If the original tree
/// already contained the data item, the original tree is returned.
TreeTy* Add_internal(value_type_ref V, TreeTy* T) {
if (isEmpty(T))
return CreateNode(T, V, T);