c++ qt QGroupBox

#include "mainwindow.h"

#include 
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#include 
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int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    auto *window = new QWidget;

    // Create a QVBoxLayout to arrange widgets vertically within the window
    auto *mainLayout = new QVBoxLayout(window);

    auto *button2 = new QPushButton("Two");

    auto  *horizontalGroupBox = new QGroupBox("Horizontal layout");
    auto *layout = new QVBoxLayout;

    for (int i = 0; i < 10; ++i) {
        auto   *button = new QPushButton(QObject::tr("%1").arg(i+1));
        layout->addWidget(button);
    }
    horizontalGroupBox->setLayout(layout);



    mainLayout->addWidget(horizontalGroupBox);

    mainLayout->addWidget(button2);



    window->show();
    return a.exec();
}