Is it possible to declare subclass objects in another subclass?

Question

I am pretty new to computing, especially to C++ and the functionality that it provides. Please be gentle with the bashing :)

I would like to ask if it is possible to declare a subclass object in another subclass. For example, can I have

class Shape {
...
};

class Square: public Shape {
..
};

class Cube: public Shape {
...
Square sq1;
...
};

I am asking this since there is a fatal error LNK2019 when I tried to compile, but my IDE is not highlighting anything specific.

You should post a sscce with the full error message. We cannot guess all the subtleties of your code otherwise. — Hiura, Oct 27 '15 at 10:31
Nothing wrong with your code per se, see [here](http://cpp.sh/4tlx). — Jonas Byström, Oct 27 '15 at 10:37

score 0 · Accepted Answer · answered Oct 27 '15 at 10:31

Sure. There's nothing particularly different about Square than from any other class. Just the fact that it happens to be a subclass of another class makes no practical difference in this context.

Just like you can have:

class Shape { ... };

class Square { .. };

class Cube: public Shape { ... Square sq1; ... };

You can also have:

class Shape { ... };

class Square : public Shape { .. };

class Cube: public Shape { ... Square sq1; ... };

Of course, whether something is a subclass of another class changes which methods the class instance has, since it's going to inherit public methods from its superclass.

Is it possible to declare subclass objects in another subclass?

1 Answers1