#if QT_VERSION >= 0x050000
#include <QtWidgets/QMainWindow>
#else
#include <QtGui/QMainWindow>
#endif

error: C1083: Cannot open include file: 'QtGui/QMainWindow': No such file or directory

#if QT_VERSION >= 0x050000
#include <QtWidgets/QMainWindow>
#else
#include <QtGui/QMainWindow>
#endif

#include <QtWidgets/QMainWindow>

#if QT_VERSION >= 0x050000
    #include <QtWidgets/QMainWindow>
    #else
    #include <QtGui/QMainWindow>
    #endif

greaterThan(QT_MAJOR_VERSION, 4) {
        QT += widgets
        DEFINES += HAVE_QT5
    }

#ifdef HAVE_QT5
    #include <QtWidgets/QMainWindow>
    #else
    #include <QtGui/QMainWindow>
    #endif