[Cs3] Friend functions in class diagrams

[Mikhail Nesterenko]

This is courtesy of one of the students.
--
Mikhail

> 
> I found this website:
> 
> http://csci.csusb.edu/dick/samples/uml1b.html
> 
> And other sources, that say this:
> 
> We sometimes need an operation that has full access to a classes private
> information and yet must not be applied to a single object. In C++, for
> example, we have "friend functions" and "friend operations". These are
> indicated by placing the stereotype "<<friend>>" in front of the operation
> in the UML class diagram.
>