Assigning new QStyle

[seux]

Hello everyone,
I want to create my own Style, so I created a class which inherits QStyle. This class does till now nothing

//MyStyleClass.h
class MyStyle : public QStyle
{
    Q_OBJECT
public:
    MyStyle();
 
    void polish(QPalette &palette);
}

//MyStyleClass.h
class MyStyle : public QStyle
{
    Q_OBJECT
public:
    MyStyle();
    
    void polish(QPalette &palette);
}

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//MyStyleClass.cpp
MyStyle::MyStyle()
{
}
 
void MyStyle::polish(QPalette &palette)
{
}

//MyStyleClass.cpp
MyStyle::MyStyle()
{
}

void MyStyle::polish(QPalette &palette)
{
}

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My test programm is just a dialog box with a button assigned. But how can I assign the new Style to my programm?
I tried it out in the main() function via:

QApplication::setStyle(new MyStyle);

QApplication::setStyle(new MyStyle);

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but I just get an error from the compiler which says:
cannot allocate an object of abstract type 'MyStyle'
because the following virtual functions are pure within 'MyStyle':
virtual void QStyle::drawPrimitive(QStyle::PrimitiveElements, const QStyleOption*, QPainter*, const Qwidget*) const;
and a lot more functions