Base Class Pointer doesn't see members of Derived

Question

Here is my code. I don't understand why I don't reach with b->x ;

main.cpp

#include <iostream>
#include "Nesne.h"
using namespace std;

int main()
{
    Derived obj;
    Base *b=&obj;

    b->a=2;
    b->x=3;


    return 0;
}

Nesne.h

#ifndef NESNE_H
#define NESNE_H


class Base
{
   public:
    int a;

    Base();
    virtual ~Base();
protected:
private:
};

class Derived : public Base
{
public:
int x;
  Derived(){};
};

#endif // NESNE_H

Answer 1

Inheritance goes in the other direction.

A pointer to a Derived object can see Base members, but a pointer to Base cannot see Derived members. There is no virtual for data members, and even for functions it would be virtual only if declared so in Base. (virtual lets you access a Derived version of a function through a Base pointer or reference).

Since the member you want is there, even though it can't be accessed that way, you could use static_cast to access it:

static_cast<Derived*>(b)->x = 3;