No. Structs can't contain functions.
Welcome to C.
User-defined functions that you call (explicitly), of course.2. How to replace operator overloading kind of thing? Will struct vars behave just like class objects?
There are no "objects" in C. They will behave like variables. No more, no less.
Yes and no. Yes, it will work, but it might not work depending on what you do.3. How to replace object handling kinda stuff? E.g. If I have an object of a class as member of some other class in C++, will simply replacing two classes with two diff. structures suffice? And in that order, struct vars. of these 2 diff. classes will behave like objects behaved in C++?
Overloaded operators will stop working, for example.
Private/public/protected will stop working.
Etc.