#include "mainwindow.h" #include #include "loginwindow.h" int main(int argc, char *argv[]) { QApplication a(argc, argv); needLogin: LoginWindow l; l.showFullScreen(); MainWindow w; int rec = l.exec(); if (rec !=QDialog::Accepted ) { goto needLogin; } // l.deleteLater(); w.showFullScreen(); return a.exec(); }