how to compile the DMG file?

[entomoio]

how to use g++ to complile main.cpp?

executing the following command gives an error:

$ g++ barrier/src/gui/src/main.cpp

In file included from barrier/src/gui/src/main.cpp:22:
barrier/src/gui/src/QBarrierApplication.h:23:10: fatal error: 'QApplication' file not found

#include
^~~~~~~~~~~~~~
1 error generated.