The program_options package ease the way to implement the program cmd interface. But what I found is that as the interface getting bigger the main() program gets longer and longer and is hard to read, because a lot of conditional branch statements have to be used. In general, the declaration of the options are at the beginning of the program and the use of the options are at somewhere afterwards. This cause the program hard to maintain. I'm wondering if there is any OO way to handle this problem. Then the main program could be easily maintained and understood.