That said, the only difference between a struct and a class is that struct member defaults to public, and class members default to private.
In C++ land, this would be true.
C doesn't let you write methods within structs. C structs don't even have inheritance. No virtual table is generated. There is no single-dispatch mechanism.
That said, the only difference between a struct and a class is that struct member defaults to public, and class members default to private.