#include <QtGui/QApplication>
#include "qt_hello_world.h"

int main(int argc, char *argv[])
{
	QApplication a(argc, argv);
	qt_hello_world w;
	w.show();
	a.connect(&a, SIGNAL(lastWindowClosed()), &a, SLOT(quit()));
	return a.exec();
}

#include "qt_hello_world.h"

qt_hello_world::qt_hello_world(QWidget *parent, Qt::WFlags flags)
	: QMainWindow(parent, flags)
{
	ui.setupUi(this);
}

qt_hello_world::~qt_hello_world()
{

}

#ifndef QT_HELLO_WORLD_H
#define QT_HELLO_WORLD_H

#include <QtGui/QMainWindow>
#include "ui_qt_hello_world.h"

class qt_hello_world : public QMainWindow
{
	Q_OBJECT

public:
	qt_hello_world(QWidget *parent = 0, Qt::WFlags flags = 0);
	~qt_hello_world();

private:
	Ui::qt_hello_worldClass ui;
};

#endif // QT_HELLO_WORLD_H

#include "../../qt_hello_world.h"
#if !defined(Q_MOC_OUTPUT_REVISION)
#error "The header file 'qt_hello_world.h' doesn't include <QObject>."
#elif Q_MOC_OUTPUT_REVISION != 59
#error "This file was generated using the moc from 4.2.2. It"
#error "cannot be used with the include files from this version of Qt."
#error "(The moc has changed too much.)"
#endif

static const uint qt_meta_data_qt_hello_world[] = {

 // content:
       1,       // revision
       0,       // classname
       0,    0, // classinfo
       0,    0, // methods
       0,    0, // properties
       0,    0, // enums/sets

       0        // eod
};

static const char qt_meta_stringdata_qt_hello_world[] = {
    "qt_hello_world\0"
};

const QMetaObject qt_hello_world::staticMetaObject = {
    { &QMainWindow::staticMetaObject, qt_meta_stringdata_qt_hello_world,
      qt_meta_data_qt_hello_world, 0 }
};

const QMetaObject *qt_hello_world::metaObject() const
{
    return &staticMetaObject;
}

void *qt_hello_world::qt_metacast(const char *_clname)
{
    if (!_clname) return 0;
    if (!strcmp(_clname, qt_meta_stringdata_qt_hello_world))
	return static_cast<void*>(const_cast<qt_hello_world*>(this));
    return QMainWindow::qt_metacast(_clname);
}

int qt_hello_world::qt_metacall(QMetaObject::Call _c, int _id, void **_a)
{
    _id = QMainWindow::qt_metacall(_c, _id, _a);
    if (_id < 0)
        return _id;
    return _id;
}

#ifndef UI_QT_HELLO_WORLD_H
#define UI_QT_HELLO_WORLD_H

#include <QtCore/QVariant>
#include <QtGui/QAction>
#include <QtGui/QApplication>
#include <QtGui/QButtonGroup>
#include <QtGui/QMainWindow>
#include <QtGui/QMenuBar>
#include <QtGui/QStatusBar>
#include <QtGui/QToolBar>
#include <QtGui/QWidget>

class Ui_qt_hello_worldClass
{
public:
    QMenuBar *menuBar;
    QToolBar *mainToolBar;
    QWidget *centralWidget;
    QStatusBar *statusBar;

    void setupUi(QMainWindow *qt_hello_worldClass)
    {
    qt_hello_worldClass->setObjectName(QString::fromUtf8("qt_hello_worldClass"));
    qt_hello_worldClass->setObjectName("qt_hello_worldClass");
    menuBar = new QMenuBar(qt_hello_worldClass);
    menuBar->setObjectName(QString::fromUtf8("menuBar"));
    qt_hello_worldClass->setMenuBar(menuBar);
    mainToolBar = new QToolBar(qt_hello_worldClass);
    mainToolBar->setObjectName(QString::fromUtf8("mainToolBar"));
    qt_hello_worldClass->addToolBar(mainToolBar);
    centralWidget = new QWidget(qt_hello_worldClass);
    centralWidget->setObjectName(QString::fromUtf8("centralWidget"));
    qt_hello_worldClass->setCentralWidget(centralWidget);
    statusBar = new QStatusBar(qt_hello_worldClass);
    statusBar->setObjectName(QString::fromUtf8("statusBar"));
    qt_hello_worldClass->setStatusBar(statusBar);

    retranslateUi(qt_hello_worldClass);

    QSize size(600, 400);
    size = size.expandedTo(qt_hello_worldClass->minimumSizeHint());
    qt_hello_worldClass->resize(size);


    QMetaObject::connectSlotsByName(qt_hello_worldClass);
    } // setupUi

    void retranslateUi(QMainWindow *qt_hello_worldClass)
    {
    qt_hello_worldClass->setWindowTitle(QApplication::translate("qt_hello_worldClass", "qt_hello_world", 0, QApplication::UnicodeUTF8));
    Q_UNUSED(qt_hello_worldClass);
    } // retranslateUi

};

namespace Ui {
    class qt_hello_worldClass: public Ui_qt_hello_worldClass {};
} // namespace Ui

#endif // UI_QT_HELLO_WORLD_H

Ниже приводится текст простейшей Qt программы:

 1 #include <qapplication.h>
 2 #include <qlabel.h>
 3 int main(int argc, char *argv[])
 4 {
 5     QApplication app(argc, argv);
 6     QLabel *label = new QLabel("Hello, Qt!", 0);
 7     app.setMainWidget(label);
 8     label->show();
 9     return app.exec();
10 }

QLabel *label = new QLabel("Hello, Qt!", 0);
a.setMainWidget(label);
label->show();