I'm new to C++ was wondering about functions

[splendorman]

Hey, i'm attempting to create a crude circumference program with a radius and a diameter mode. I'm under the impression I can create the modes with functions. I'm having an odd time calling them, and creating a user input to access the different modes.
So basically, can someone explain functions in laymens terms?

[Raezzor]

http://www.cplusplus.com/doc/tutorial/functions/

That should help.

[splendorman]

Nevermind fixed it. turns out I forgot to prototype it. I feel silly.