Error accessing pointer to class member in main

[starkid]

Just

And don't forget to take and pass a parent to the QMainWindow's constructor. //just to avoid future problems like memory leak/object slicing.

How does that work? QMainWidget can take a QWidget as a parent, but QApplication is not derived from QWidget. Is it necessary to create an intermediate widget in main to pass as a parent?

Also, there is still a problem. I'm getting:

error: no matching function for call to ‘QObject::connect(QPushButton*&, const char [11], QApplication*, const char [8])

The first argument, QPushButton*&, looks like a problem with mainWindow.quit.