Hi,
i am very new in inform7 and i hope that this is not a dumb question 
i am on the way to develope my first adventure and in my story it is neccessary to visit each room.
i know the statement [if unvisited], but is there a way to see all rooms which are unvisited?
or are there functions which i can use to output all my unvisited rooms?
or at least, maybe somebody can give me a tip how i can implement such a feature 
all the best
caroline
Sure! You can do something like this:
Every turn:
if every room is visited:
end the story saying "You have won";
otherwise:
say "You still need to visit [list of unvisited rooms]."
“Visited/unvisited” is a built-in either/or property (see writing with Inform 3.6), which gives you adjectives (see writing with Inform 6.2) that you can use in building lists like “list of unvisited rooms” and checking conditions like “if every room is visited” (or “if a room is unvisited”). And there are lots and lots more things you can do with them; it depends on exactly what you want to happen.
You can also “let the place be a random unvisited room” and such if you want to give the player a destination. This phrase returns “nothing” if there are no unvisited rooms left.