QT       += core gui widgets

CONFIG += console

TARGET = untitled2
TEMPLATE = app

SOURCES += main.cpp

#include <QApplication>
#include <QMainWindow>
#include <QTextStream>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QMainWindow w;
    w.show(); 

    QTextStream out(stdout);
    out << "hello\n";
    out.flush();

    return a.exec();
}