Dan Zwell wrote:
> "+=" will actually work on any class that has "+" defined, including
> custom classes. I assume it is the same with "-=", "*=", "/=", "&&=",
> "||=", and any others that I may have missed...

That is correct (you missed %=, |=, &=, ^=, <<=, >>=, **= and whatever /I/
may have missed), except that in case of && and || it is not necessary for
the class to have anthing defined, because those aren't methods and they
work independently of the object's class.