Having worked with monobehaviour and processing before, is it possible to create the same paradigm both frameworks use which basically is writing all code in two main functions, start/setup and update/draw and completely hiding the main function. If not,are there any ways to atleast imitate it?

Having worked with monobehaviour and processing before, is it possible to create the same paradigm both frameworks use which basically is writing all code in two main functions, start/setup and update/draw. To further elaborate, much like working in unity when creating a new script the user is presented with two functions a start and an update. The first function always gets called on the first frame while the latter gets called every frame there is no main function present only these two. I'd like to imitate that same structure on to c++.