How to convert C Code to C

Question

I've got some C++ programme.

Numerous classes, their member functions, constructors, and destructors, along with a few template classes and a tonne of C++ code, are defined in the code.

I must now translate the source into ordinary C code.

I also have the following inquiries:

1. Is there a programme that converts header files and C++ code?

2.Will I need to completely rewrite the code (removing constructors and destructors and moving that code into some init() and deinit() functions; changing classes to structures; making existing member functions into function pointers in those newly defined structures and then calling those functions using function pointers, etc.)?

3. What C++-specific code-data constructs or semantics must I be aware of while converting from C++ to C if I have to do it manually?