Get member of parent struct - c++

Question

I've created an SSCE to better explain this.
In a class, I have a variable, a struct, and a declaration of the struct. Within that struct is a constructor, a variable, a struct and a declaration of that struct. And inside THAT struct is a constructor.
So is goes Mother > Daughter > GDaughter aka class > struct > struct
mother.h
#ifndef MOTHER_H
#define MOTHER_H
#include <QSplitter>
class Mother : public QSplitter
{
Q_OBJECT
public:
Mother(int);
int age;
struct Daughter
{
Daughter();
int height1;
struct GDaughter
{
GDaughter();
};
GDaughter *kate;
};
Daughter *tina;
};
#endif // MOTHER_H
Now let's take a look at the constructors/source. Here lies my issue.
mother.cpp
#include "mother.h"
#include <QDebug>
Mother::Mother(int a)
{
age = a;
tina = new Daughter();
}
Mother::Daughter::Daughter()
{
qDebug() << age; //Not going to work... I get it. Daughter isnt a derived class
height1 = 10;
kate = new GDaughter();
}
Mother::Daughter::GDaughter::GDaughter()
{
qDebug() << height1; //Why not? The GDaughter instance is a member of Daughter!
}
Both qDebug() lines throw is not a type name, static, or enumerator.
The goal is to create "child" structs dynamically. So a parent struct might have 0 child structs, 1 child struct, or even 100 child structs. That is why I am using structs instead of derived classes. This setup looks like it would work except for the problem where "parent" variables can't be accessed.
I will include the other files anyway:
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "mother.h"
#include <QDebug>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
mom = new Mother(50);
}
MainWindow::~MainWindow()
{
delete ui;
}
main.cpp
#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include "mother.h"
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
Mother *mom;
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
If I am misunderstanding how to go about making something like this then let me know.
Thanks for your time.
AFTER ANSWER
In the mother.h I added parent pointers:
struct Daughter
{
Daughter(Mother *p); //Here
int height1;
struct GDaughter
{
GDaughter(Daughter *p); //And here
};
GDaughter *kate;
};
and in mother.cpp I filled in the needed code:
Mother::Mother(int a)
{
age = a;
tina = new Daughter(this); //Here
}
Mother::Daughter::Daughter(Mother *m) //Here
{
qDebug() << m->age; //Here
height1 = 10;
kate = new GDaughter(this); //Here
}
Mother::Daughter::GDaughter::GDaughter(Daughter *d) //Here
{
qDebug() << d->height1; //Here
}

Answer 1

keep pointer(std::weak_ptr if you use smart pointers, for example) to parent class object in nested object.
explicit MainWindow(QWidget *parent = 0);
look at Qt code here, you pass pointer to the parent object in constructor,
if parent is nullptr that means MainWindow has no parent object, Also you can keep
pointer to MainWindow parent object and then static_cast it to exact class
#include <iostream>
class A {
class B{
public:
B(A *p):parent(p) { parent->hello(); }
private:
A *parent;
};
public:
A() { b = new B(this); }
void hello() { std::cout << "hello world" << std::endl; }
private:
B *b;
};