Does NetBeans facilitate code-completion for C++? If yes then what are the shortcuts to use it?
Yes, it does.
You'll need C++ version of NetBeans or you'll need to download the C/C++ plug-in from plug-ins menu.
I can't remember all shortcuts since I haven't used in some time, but CTRL+SPACE is the one I used used the most.
Once you start typing code, you'll get menus under each keyword you start typing. Arrows and CRTL+SPACE are used to select available options.