i am using EA to model some c-components. i know that EA can't be used efficiently with C language but i am trying to stick to the intended usage of each element as possible as i can.
my question... i am modelling a C-file using a class and functions using operations inside this class. my functions need to receive some values before they start and send some other values before after they finish, can i represent this in the model using Operation's Pre and Post-Coditions or doesn't fit in this place? and if not how i should represent this in the model in a correct way
I don't think that this is part of pre/post conditions. Rather you would need an interface to talk to some object model. As I see it, your main component is written in C and it just uses some OO stuff. In that case you need an adapter you can use in your C code. That would probably consist of a send(module, operation, parameters...)
and vice versa a receive(module, values...)
which will do the synchronization with the OO stuff. Details for that will not go in this answer since there need to be clarified lots of constraints.