Sometimes, when working with small classes, it\'s a pain in the ass to separate the implementation in a .cpp file, so I put all the code in the header file (kids, don\'t do
Perhaps Lzz is what you're looking for.
I'm guilty of this as well - although I've never really thought about automating the split before, as there are usually related project and test files to touch.
The idea of automating this is interesting, though. The most promising tool I see out there is this one:
http://os.inf.tu-dresden.de/~hohmuth/prj/preprocess/
It may be more trouble than it is worth but with a programmer's editor such as Epsilon you can write a routine to do that and bind it to any key sequence you like. However, I now make the header up front and use the programmer's editor to jump between them, create the function headers, fill in the class names (from the file name) and generally make my life easier. There is an up-front investment in time though.