This tool is really useful ! Hope you will like it:
http://root.cern.ch/drupal/content/cint
Simply, an interpreter for C/C++
I also heard about another interpreter but can't find it, thye say it is better, but this one did good enough for me ! :D
What would you need it for? And why an interpreter instead of a compiler?
umm .. It is easier ? faster to code ?
I dunno, its like comparing coding with python or ruby with coding with normal C compiler .. it is common sense that its more fun on python !