No console pops up
Like all "Hello World" C programs it must be run from a command prompt.

No console pops up because your code does not include a WinMain entry point, code to create a Windows console, connect the stdin and stdout streams, and make it act as expected. If you use the Qt core then you can have this done for you (CONFIG += console). Since you do not want Qt dependencies you must do it for yourself. Have a look at http://dslweb.nwnexus.com/~ast/dload/guicon.htm (you might have to adjust for MingW).