destroing nested layout

[mastupristi]

Suppose I have the following code

MainWindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QtGui/QDialog>
 
class MainWindow : public QDialog
{
    Q_OBJECT
 
public:
    MainWindow(QWidget *parent = 0);
    ~MainWindow();
};
 
#endif // MAINWINDOW_H

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QtGui/QDialog>

class MainWindow : public QDialog
{
    Q_OBJECT

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

#endif // MAINWINDOW_H

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MainWindow.cpp

#include "mainwindow.h"
#include <QHBoxLayout>
#include <QVBoxLayout>
#include <QLabel>
 
MainWindow::MainWindow(QWidget *parent)
    : QDialog(parent)
{
    QHBoxLayout *mainLayout = new QHBoxLayout(this);
    QHBoxLayout *slaveLayout = new QVBoxLayout(this);
 
    slaveLayout->addWidget(new QLabel("A0"));
    slaveLayout->addWidget(new QLabel("A1"));
 
    mainLayout->addLayout(slaveLayout);
    mainLayout->addWidget(new QLabel("B0"));
 
    setLayout(mainLayout);
}
 
MainWindow::~MainWindow()
{
    delete layout();
}

#include "mainwindow.h"
#include <QHBoxLayout>
#include <QVBoxLayout>
#include <QLabel>

MainWindow::MainWindow(QWidget *parent)
    : QDialog(parent)
{
    QHBoxLayout *mainLayout = new QHBoxLayout(this);
    QHBoxLayout *slaveLayout = new QVBoxLayout(this);
    
    slaveLayout->addWidget(new QLabel("A0"));
    slaveLayout->addWidget(new QLabel("A1"));
    
    mainLayout->addLayout(slaveLayout);
    mainLayout->addWidget(new QLabel("B0"));

    setLayout(mainLayout);
}

MainWindow::~MainWindow()
{
    delete layout();
}

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does the destrictor delete both mainLayout and slaveLayout?
Or do I need to modify as follows:

MainWindow::~MainWindow()
{
    delete layout()->layout();
    delete layout();
}

MainWindow::~MainWindow()
{
    delete layout()->layout();
    delete layout();
}

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thanks

[Lykurg]

does the destrictor delete both mainLayout and slaveLayout?

Yes. You have to do nothing.

[mastupristi]

Yes. You have to do nothing.

Ok, that's fine

Now I wonder if widgets are deleted too.

If I have the following contructor:

#include "mainwindow.h"
#include <QHBoxLayout>
#include <QVBoxLayout>
#include <QLabel>
 
MainWindow::MainWindow(QWidget *parent)
    : QDialog(parent)
{
    QHBoxLayout *mainLayout = new QHBoxLayout(this);
    QHBoxLayout *slaveLayout = new QVBoxLayout(this);
 
    static QLabel A0("A0");
    slaveLayout->addWidget(&A0);
    slaveLayout->addWidget(new QLabel("A1"));
 
    mainLayout->addLayout(slaveLayout);
    mainLayout->addWidget(new QLabel("B0"));
 
    setLayout(mainLayout);
}

#include "mainwindow.h"
#include <QHBoxLayout>
#include <QVBoxLayout>
#include <QLabel>
 
MainWindow::MainWindow(QWidget *parent)
    : QDialog(parent)
{
    QHBoxLayout *mainLayout = new QHBoxLayout(this);
    QHBoxLayout *slaveLayout = new QVBoxLayout(this);
    
    static QLabel A0("A0");
    slaveLayout->addWidget(&A0);
    slaveLayout->addWidget(new QLabel("A1"));
    
    mainLayout->addLayout(slaveLayout);
    mainLayout->addWidget(new QLabel("B0"));
 
    setLayout(mainLayout);
}

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and desctructor:

MainWindow::~MainWindow()
{
    delete layout();
}

MainWindow::~MainWindow()
{
    delete layout();
}

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does the destructor destroy also QLabel A0, "A1" and "B0"? I wonder if "A1" and "B0" are deallocated, and what about A0 that is statically allocated

thanks