CODEWITHSUNDEEP
c++inheritanceprotectedprivate-members
vvavepacket
vvavepacket

Reputation: 1929

protected members are not accessible in derived classes

Why is that protected members in the base class where not accessible in the derived class?

class ClassA
{
public:
    int publicmemberA;

protected:
    int protectedmemberA;

private:
    int privatememberA;

    ClassA();
};

class ClassB : public ClassA
{
};

int main ()
{
    ClassB b;
    b.protectedmemberA; // this says it is not accesible, violation?
    //.....
}

Upvotes: 6

Views: 8247

Answers (3)

juanchopanza
juanchopanza

Reputation: 227390

Because the protected members are only visible inside the scope of class B. So you have access to it here for example:

class ClassB : public ClassA
{
    void foo() { std::cout << protectedMember;}
};

but an expression such as

someInstance.someMember;

requires someMember to be public.

Some related SO questions here and here.

Upvotes: 3

Component 10
Component 10

Reputation: 10487

You can only access protectedmemberA from within the scope of B (or A) - you're trying to access it from within main()

Upvotes: 0

Luchian Grigore
Luchian Grigore

Reputation: 258568

You can access protectedmemberA inside b. You're attempting to access it from the outside. It has nothing to do with inheritance.

This happens for the same reason as the following:

class B
{
protected:
   int x;
};

//...

B b;
b.x = 0;  //also illegal

Upvotes: 10

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