You would be suprised how fast it is to reverse engineer ones executable
code into a human readable.
IDA Pro does this (http://www.datarescue.com/idabase/) by taking the known
library code if VC++, BC,.... and write the assembler code into readable.

Although it will not generate the original C++ source code, at least you can
find how it is implemented.
What functions you used, in what order,...

A few years ago, I tried to create a protection key. For months I was
convinced that it was not easy to crack (using a dongle) untill I used IDO
Pro out of curiosity and not only did I crack it in 30 minutes, I also
managed to make my program activate all options in that dongle. So logically
I made the code a little harder to reverse engineer. :-)

I have not used IDA Pro for many years now, so I have not kept track of the
new implementations.