It's harder to use classes in C because the language doesn't fully support object programming.
But you can do object-style programming; use struct instead of class and you can create an "object" with member functions and attributes. I don't think C supports private or protected struct members, and it certainly doesn't support the virtual keyword so good luck with your manual implementation of the virtual function table. C also doesn't support overloaded function names or operators, and for proper object-style encapsulation you'll have to limit yourself to one class per C file and use "static" a lot. And lots of void pointers. And by the way there is no "this" pointer in C.
So while you can do object oriented programming in C it definitely won't be the same way you write C++ programs, unless you get some kind of C++ to C precompiler (which is all C++ was in the early days; I think Bjarne called it "C with classes"), and if you're going to do that then you may as well stick with the C++ compiler.