connect(ui->cut_action, &QAction::triggered, this, &MainWindow::cut_triggered);
connect(ui->exit_action, &QAction::triggered, this, &MainWindow::exit_triggered);
connect(ui->cut_action, &QAction::triggered, this, &MainWindow::cut_triggered);
connect(ui->exit_action, &QAction::triggered, this, &MainWindow::exit_triggered);