How to do a "CREATE DATABASE" and then connect to it?

After you do a "CREATE DATABASE", how do you programatically
connect to what you just created?

In the psql monitor, you'd use the "\c" command.

If the DATABASE already exists when you connect to postgresql,
you use the name when you connect (e.g. "dbname=...").

I'm getting the impression I need to do this in multiple steps,
which is workable, but seems a little silly.