#include <QApplication>
#include <QPushButton>
#include <QMessageBox>

int main(int argc, char **argv) {
    QApplication app(argc, argv);

    QPushButton button("Clique-moi !");
    QObject::connect(&button, &QPushButton::clicked, [&]() {
        QMessageBox::information(nullptr, "Salut", "Bonjour, Patrick !");
    });

    button.resize(200, 100);
    button.show();

    return app.exec();
}