You can absolutely translate object oriented C++ to vanilla C. As a young teenager I would routinely convert C++ from books I got from my parents/library to C, because I didn't have access to a C++ compiler. The process isn't that difficult....

Take the members of the C++ object and create a struct to hold the data then create a 'constructor' function for populating that data. Afterwards you just call the member functions of the original class, as simple C functions, and pass the struct as the first argument.

This in fact is what the actually happens at the assembly level when using a C++ compiler! The idea of an 'object' is purely an abstraction!