Data stream help

gurumare_at_gmail.com
Date: 03/30/05 

Date: 29 Mar 2005 19:54:48 -0800

Howdy, I am just learning c++ and of course i am doing the classic
"gradeBook" program, but i am trying to figure out a way to save my
data so that the next time my prog is opened it will still be there.
Someone told me to look at the 'data stream' but i do not know what
that is. Please help (specifics/explanations are always appreciated)