Question

I’m new to C++, and I’m familiar with Java. The first thing I was wondering about when I started looking at C++ code is that classes themselves (not the members) don’t have access specifiers such private, protected and public. Exemples here and here.

public class A { // This line.
  private class B { } // Not this line.
}

Why is that so?

Answer 1

There’s no access modifier at the level of classes, since the language has no concept of package. But there is at the level of data members, member functions and inheritence:

class Foo {};
class Bar : public Foo {

 public:
  void bar() const {}
 private:
  int bar_(float) {}
  int a, b, c;

};

The closest you can get is declaring nested classes inside a class:

class Foo {

  struct Bar0 {
    void bar0() const {}
  };
  struct Bar1 {
    Bar0 b0;
    Bar1() { b0.bar0();}
  };

};