CODEWITHSUNDEEP
c++oopinheritance
user1240679
user1240679

Reputation: 6969

Initialise protected data members from derived class constructor

I am dusting off my C++ learnings and trying to write a program here.

class Quad{
public:
Quad(){}
protected:
vec _topLeft, _topRight, _bottomLeft, _bottomRight;
};

class IrregularQuad : public Quad{
public:
IrregularQuad(vec topLeft, vec topRight, vec bottomLeft, vec bottomRight)
: _topLeft(topLeft), _topRight(topRight), _bottomLeft(bottomLeft), _bottomRight(bottomRight)
{}
};

I am getting a compile error on the above Dervied class contractor saying: Member initializer _topLeft does not name a non-static data memeber or base class (similar error for other members as well)

I can't get my head around what's going worng. Is it that I can't initialise protected members using Initalizer list or something?

Upvotes: 2

Views: 2124

Answers (3)

doctorlove
doctorlove

Reputation: 19282

This is a duplicate of error C2614: 'ChildClass' : illegal member initialization: 'var1' is not a base or member

You can only initialise members or base classes in the initialiser list.

Upvotes: 0

jrok
jrok

Reputation: 55425

Is it that I can't initialise protected members using Initalizer list or something?

Right. Only class' own members can be initialized in constructor initializer list (You can, OTOH, assign to them in constructor's body). The base subobjects are initialized first.

You'll need to somehow delegate the work to one of base class' constructors:

class Base {

    explicit Base(int i) : m(i)
    {}
protected:
    int m;
};

class Derived : public Base {
    explicit Derived(int i) : Base(i)
    { }
};

Upvotes: 3

Michael Kristofik
Michael Kristofik

Reputation: 35208

You don't initialize base class members in a derived class' initializer list. You can add a constructor to Quad to do that for you, or you can set them yourself in the body of the derived class constructor.

Upvotes: 1

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