So I've been taking a C++ in school and sometimes it seems like I've to turn to sources other than my prof for help. Hence after some googling, I'm here. Now I have a few questions.

I've been reading my text and prof's lecture notes, and there are somethings that I can't get my mind around.

1)
Code:
void printClassInfo( void )
What exactly does the void in brackets do? Would you need the whole program to answer the question? I know what something like " void displayMessage( string courseName ) " does [sorry for not posting it in code, I figured it would "break the layout"].

2) How exactly does the getline command work? An example to understand it's working would be very helpful, thanks in advance.

3) What is the purpose of something like "using namespace std;" or "using std: :cout;" or "using std: :cin" etc?

Any help on these three questions would be really helpful, and hopefully play an important role when the class advances further. Also, I have no previous exposure to C - I know it's a handicap, but I hope that it's not something that'll cripple me. Thanks in advance, guys/gals!