QUESTION: HOW TO PASS PARAMETERS BETWEEN TWO PROGRAMS??

Question

Hello!

I'm new in c# programming and I need you to help me with this problem:

I've created two programs in C#. The first one called "FM" and is only a program with a lot of functions. The second one called "MCDU" and is the main program.
The problem is that I need to pass some parameters of "MCDU" to "FM" in order that the second program executes with this parameters one of the functions that has in its code. So, how I pass from "MCDU" the parameters to "FM" and also how I return new parameters from "FM" to MCDU?

Thanks in advance and if you need a better explanation please ask for it!

Franky