Nested classes, inheritance and shared pointers in C++ - c++

Question

The program below fails, obviously, in the return expression:
#include <memory>
class Base {
public:
class Nested {
public:
int c;
};
};
class A : public Base {
public:
class Nested : public Base::Nested {
public:
int c = 1;
};
};
class B : public Base {
public:
class Nested : public Base::Nested {
public:
int c = 2;
};
};
int main() {
std::shared_ptr<Base> X = std::make_shared<A>();
return X::Nested.c;
};
How can I get Nested.c value of X?
In other words, I have one base class (Base) and two derived classes (A and B). Each derived class has a nested class (Nested). I want to called Nested.c from an instance X, which is dynamically selected as one of the derived classes.

Answer 1

Probably just a misconception about nested classes. A Nested class does not magically add members to it's parent class. You need to do that manually, for example:
class Base {
public:
class Nested {
public:
int c;
};
Nested nested; // member of nested class Base::Nested.
};
Keep in mind that Base::Nested, A::Nested and B::Nested are all different classes. Allthough they look similiar they are not related at all.
Maybe the following is what you want:
#include <memory>
class Base {
private:
class Nested {
public:
int c;
};
Nested nested; // member of nested class Base::Nested.
public:
virtual int getC() const { return this->nested.c; }
};
class A : public Base {
private:
class Nested {
public:
int c = 1;
};
Nested nested; // member of nested class A::Nested.
public:
int getC() const override { return this->nested.c; }
};
class B : public Base {
private:
class Nested {
public:
int c = 2;
};
Nested nested; // member of nested class B::Nested.
public:
int getC() const override { return this->nested.c; }
};
int main() {
std::shared_ptr<Base> X = std::make_shared<B>();
return (*X).getC();
};
Each class has it's own member of it's own nested class and returns c with a virtual getter.