The easiest for C++ would be to use Qt tools.
Check if you've got installed QT develop packages.
(K Menu - Applications - Development - QT Designer)
QT Designer is kind of a MS V. Studio.
If it is not installed in your system, sure the is an rpm file in your distro's CD's.
(For MDK9.1: libqt3-devel-3.1.1-13.1mdk )
You can also choose KDevelop as GUI
On the other way, you could choose to develop for Gnome and/or GTK2 or even C# & "Mono" architecture, but I think that's at least harder for beginnings and could be less productive for a newbie.