Is it possible to add some functionality to a class without subclassing?
<p>In Ojective-C there is something called Categories which allow the user to add methods from outside the original .h or .m file (objective-c's version of .cpp)
I wonder if there exist such functionally in C++.?</p>

<p>I specially want implement &lt;&lt; operator for debugging and maybe others of a class that is in a library I frequently use. (And don't want to use macros since it looks ugly ;) )</p>

<p>Thanks.</p>
