Rails Route URL segment with + (plus) sign character in id is not parsed correctly

I have a TagsController class, with a route like the following (in routes.rb)

resources :tags

Now, when I go to

http://localhost:3000/tags/test

It works correctly.

However, when I go to

http://localhost:3000/tags/c++

Rails seems to be parsing the "c++" as "c ", so this results in a "404 Not Found"

Could anyone give me any instructions on how I could fix this?