ManageClassWindow::ManageClassWindow(QMainWindow * parent ) : QMainWindow (parent) { this->resize(350 , 110); DBManager dbManager ; QVector<Student> students = dbManager.getStudentList(); QStringList studentsName ; foreach (Student temp, students ) { studentsName.append(QString (temp.getName()+ " " + temp.getFamily()) + QString(" (class %1)").arg(QString::number(temp.getClassID()))); }