> Yes but this is how initially I started to write my code but then had
> the thought that since my calculations weren't computer intensive. So
> I thought why not calculate all options first and show what valid
> options exist to the user rather than looping around the options
> trying to find a valid option. Is this a good way to go.

That's entirely up to you.

However, I think most mail clients have a send button - even when you
haven't entered yet an email address!

John