GCC ( the gnu compiler collection ) is generally included on all versions of ubuntu.
If you want to use G++ ( a front end for gcc that uses C++ as the default language ) you can go to
applications->accessories->terminal and type in sudo apt-get install g++
In order to compile C++ code ( make it executable ), you would go to a terminal and type in g++ -o NameOfYourOutputFile NamesOfYourInputFile(s).
I'm on Ubuntu right now.
It usually comes with it, but just to be sure you may aswell do the following $ sudo apt-get install binutils
wait for the command to complete. Then you can simply type $ gcc myInputFiles -o myOutputFile -lstdc++
or $ g++ myInputFiles -o myOutputFile
As in myspy2plus' post, terminal is located in Applications -> Accessories. Or you can type Alt + F2; type in "bash" and make sure "run in terminal" is checked before clicking Run.
Note that the $ represents the terminal prompt and you don't type it.