Mathew Robertson wrote:
Yeah, geez. Single-rooted hierarchies of diverse functionality with a root class called "object" were discredited long ago, weren't they?
I am not suggesting a single-rooted heirarchy for *all* the classes as that would be stupid. MFC does it to support their own version of RTTI, memory leak tracking, etc. Java does it because it doesn't have templates. .NET has it because it treats every object as a COM object.
Python does it too. It's not neccessarily wrong for other languages; just C++.
hmm.... If C++ had implemented an 'Object' back in 1980, then "single rooted heirachy"s wouldn't be questioned...
We'd still be using C in that case. ;-) Bad single-rooted hierarchies are bad in principle; it doesn't depend on language. The problem occurs when the base class acquires functionality that 90% of the descendants have. The other 10% are forced to implement something that they do not support. Over time, this can lead to "spectacular" designs. All of the above examples do not fit this description; the root "object" is simply what constitutes an object in that particular language. Since in C++ everything can be an object, the root class is "void".