#include <QApplication>
#include <QMainWindow>
#include <QTabWidget>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QMainWindow w;

    auto tw = new QTabWidget(&w);
    tw->addTab(new QWidget(), "Tab-------------------------------1");
    tw->addTab(new QWidget(), "Tab-------------------------------2");
    tw->addTab(new QWidget(), "Tab-------------------------------3");

    w.setCentralWidget(tw);

    w.show();

    return a.exec();
}