Why can't I install g++?

Solution 1:

Run:

sudo apt-get update

You should always run that before installing or upgrading packages on the command-line (unless you've run it very recently). It fetches information about what packages are available in what versions from where.

You may simply be able to install g++ now, but go ahead and do as Web-E says (after running the above command), to fix any currently broken dependencies:

sudo apt-get -f install

(The -f can actually go before or after the install; the effect is the same.)

Then try installing g++ again:

sudo apt-get install g++

If that still fails, please edit your question to show any error messages (and also the output of the above two commands when you ran them). But it should succeed.