Private Inheritance Question

Hi All

I have one question. I was trying to test private inheritance and saw something which I need some help to understand.

Code:

---


class Base
{

int age;

public:
  Base(int x): age(x) {}

  int getAge()
  {
          return age;
  }
};

class Derived : private Base
{
  string name;

public:
  Derived(string x,int y):  Base(y),name(x) {}


  void getName()
 {
          cout<<"Name is="<<name<<"And Age is="<<getAge();
          cout<<age; // Compiler error as Age no accessible
 }

};

int main()
{
        B b;
        b.get();
        Derived d("nickman",12);
        d.getName();
        return 0;
}

---

So I assume that in private inheritance, all base class data members and functions inherited as private to Derived class and can be access via Derived class functions.

getAge() call from Derived class works fine but compiler give error when I accessed "age" data member.

So question is, if we have inherited privately, then how getAge() call is working fine?

Thanks

> So question is, if we have inherited privately, then how getAge() call is working fine?
Because the function itself is a public member function of Base.

> cout<<age; // Compiler error as Age no accessible
If you want this to work, and prevent just anyone from accessing the data directly, then use the 'protected:' class qualifier.

age is the base class is private, hence Derived can't access it. This doesn't change regardless of what type of inheritance you use--private is private. If you want the derived class to be able to access it, it must be protected or public. With private inheritance, all inherited members are made private to Derived, so the Base class members won't be accessible to any derived classes from Derived nor from the outside (because they're all private).

You can access GetAge just fine because it's public in Base.