How Many Battleships in Acfive Service?

The answer is "none."  The last two--the Iowa and the Wisconsin--were striken from the Naval Register in 2006.  Link.  Their demise ended a long trajectory of development which perhaps began with the Battle of the Coral Sea in 1942, the first which actively involved aircraft carriers.  Return to the question.

And FWIW I just saw a tweet saying that the world's fifth largest navy belongs to Disneyland.