For really big classes, I split their implementations into several .cpp files named Klass_File1.cpp, Klass_File2.cpp, where the header is Klass.h.
It would be great if Alt+O could switch from Klass_File1.cpp to the corresponding header. And then Alt+O from the header would switch back to the most recent implementation file viewed.
Unfortunately, alt+o cannot determine which file to switch in this case. If it tried to make "guesses" about similar file names it would probably cause a lot of false match in other cases. But there is an alternative way you can do the job. You will find a macro after the jump which is something like a simplified version of alt+o. You can easily modify it to do what you would like it to do: