This is C++:

   for (auto&& x: collection)
       x.foo();

You say you have no idea what foo is.

This is C:

   for (int i = 0; i < collection_size; i++)
      foo(collection[i]);

Now you say that which foo is being called is very obvious...

... but [1]:

  #define foo(x) x.foo(&x) 

x.foo is a function pointer and someone has been implementing OO in C (far fetched? it is literally the title of the article). With C++ at least if I M-. on foo emacs will show me all possible targets (or directly take me to foo implementation if not polymorphic); With C, good luck teaching your IDE your custom flavor of OO [2].

So, no, C and C++ are more similar than you think. The biggest difference is the presence of overloading which, in the static dispatch case, makes resolving the actual function from the function name slightly harder in C++ without tool help. Overloading has little to do with OO, although it is a form of static polymorphism.

In the dynamic case they are equivalent (well except for the fact that you have to build the vtables by hand in C and the syntax is a bit awkward.

[1] yes, yes, arguments are not protected against multiple evaluation. Sue me.

[2] with emacs of course this is actually possible, just merely hard.