c++ - main() Qt 项目中动态分配的对象

Question

我的 int main() 中有几个动态分配的对象，我应该如何在程序结束时删除它们？目前我认为我没有在程序结束时释放内存，这是主要的:

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow *w = new MainWindow;
    breadData *dat = new breadData("audit.dat");
    //link main window with bread data
    w->_link(dat);
    //show main window
    w->show();
    //execute loop
    return a.exec();
}

Answer 1

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow *w = new MainWindow;
    breadData *dat = new breadData("audit.dat");
    //link main window with bread data
    w->_link(dat);
    //show main window
    w->show();
    //execute loop
    int result = a.exec();
    delete dat;
    delete w;
    return result;
}

但是动态分配看起来没必要。
为什么不

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    breadData dat("audit.dat");
    //link main window with bread data
    w._link(&dat);
    //show main window
    w.show();
    //execute loop
    return a.exec();
}