[SOVLED] Puzzling class member and its usage in class constructor

[Karen]

I inherited a piece of code as the following:

In the header file:

namespace Ui
{
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();

private:
Ui::MainWindow *ui;
...
}

In cpp file, the class constructor as defined as below:
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)

Question is why a pointer to itself in the header file? Is this not just "this" as in C++?

Then in the constructor, ui(new Ui::MainWindow) is used in the constructor. What does it do to the constructor?

[mcosta]

Hi and welcome to devnet,

'ui' is not an instance of the MainWindow class but of the Ui::MainWindow one that is defined inside the namespace Ui.

[Karen]

@mcosta Thank you. Indeed I found the class definition for Ui::MainWindow. So the constructor initializes the member class *ui using ui(new Ui::MainWindow).