void Dialog::on_buttonBox_accepted()my first attempt so I could get the result n Mainwindow.cpp but it could be incorrect
{
     Cities.clear();
     for(int row = 0; row<ui->tableWidget->rowCount(); row++)
     {
         cities s(get_city(row),get_time(row,3),get_time(row,4));
         Cities.push_back(s);
     }
}

void Dialog::on_pushButton_clicked()// my attempt to make another button but I could not get a result in Mainwindow.cpp but could check correctly
{
    if(cities_is_filled())
    {
        Cities.clear();
        for(int row = 0; row<ui->tableWidget->rowCount(); row++)
        {
            cities s(get_city(row),get_time(row,3),get_time(row,4));
            Cities.push_back(s);
        }
    }
}

//GET RESULT
void MainWindow::on_actionAdd_train_triggered()
{
    Dialog e;
    if(e.exec())
    {
       for(auto City: e.Cities)
       {
           ui->textBrowser->append(City.city_+ " " + City.depart_+ " " +City.leave_);
       }
    }
}