Re: OO Style with Ada Containers

[Matthew Heaney <matthewjheaney@earthlink.net>]

braver <deliverable@gmail.com> writes:

> Back to your original example, why are Ordered_Maps less preferable
> than Hashed_Sets?

The hashed vs. ordered distinction would only matter if you have some
interesting order for keys, e.g. you want to iterate over the map in
alphabetical order (since the word is the key).

For this problem you can use a set or a map. In this case it's probably easiest
to use a map, but you might want to try it using a set instead, if just as an
exercise.


> My code maintains for each distinct word its overall count, and uses
> Replace_Element for updating the count -- my impression is each word is
> stored just once with that use of Ordered_Maps, no?

Right, each word (the key) is stored only once.


> Also, I don't need to give it a hash function.

Right -- sometimes synthesizing a (good) hash function is difficult, so it's
often easier to just use an ordered map.  But either hashed map or ordered map
would work here (I used a hashed map in my earlier post).


> What are the advantages of Hashed_Sets?

I don't think there are any advantages here to using a set instead of a map.