running Qt on Linux fails

[andreasM111]

Hi, i am on Linux Manjaro and want to set up newest Qt, doing one simple C++ "Hello World" program.
You see my code in the attached pic. But when I run it the cmd window closes immediately after pressing F5. No Text is put to screen.
Also the user input with "cin" seems beeing ignored. What im doing wrong?
Pic showing it on Debug/Breakpoint:

Edit: I found out that a additional
while(1);
at the end will let the window open only.
Can someone explain why it is closing else?

[sierdzio]

What happens when you run the app from terminal (not Qt Creator)?