The past months I've been busy programming a 2D JRPG (Japanese-style RPG) in C++ using the SDL library. The exploration mode is more or less done. Now I'm tackling the battle mode.

I have been unable to find any resources about how a classic turn-based JRPG battle system is structured. All I find are discussions about damage formula. I've tried googling, searching gamedev.net's message board, and crawling through C++-related questions here on Stack Exchange. I've also tried reading source code of existing open source RPGs, but without a guide of some sort it's like trying to find a needle in a haystack.

I'm not looking for a set of rules like D&D or anything similar. I'm talking purely about code and object structure design. A battle system asks the player for input using menus. Next the battle turn is executed as the heroes and the enemies execute their actions.

Can anyone point me in the right direction? Thanks in advance.