You can use Vim in two modes - one with GUI and other without GUI.
To use GUI use command -
gvim foo.cpp
To use non-gui mode give -
vim foo.cpp
OR plain vanilla mode
vi foo.cpp
It is very strongly recommended that you always use gvim instead of vim, since GUI mode
with colors will definitely improve your productivity.
The vim also gives colors but cannot set the background colors and gvim can set the
background and foreground colors.
GUI mode gvim provides the following -
You can mark the text using the mouse to do cut, copy and paste.
You can use the Menu bar which has - File, Edit, Window, Tools, Synatx and Help buttons.
Also in near future in gvim - a second menu bar will display the list of files being edited,
and you can switch files by clicking on the filenames, until then you can use
vi commands - :e#, :e#1, :e#2, :e#3, :e#4, ....so on to select the files.