#include <QtWidgets> 

class MyWidget : public QLineEdit { 
public: 
    MyWidget (QWidget* parent =0) : QLineEdit (parent) {} 
protected: 
    void keyPressEvent (QKeyEvent* k) { 
        QString text; 
        if ( k->modifiers() &Qt::ControlModifier ) text.append ("Ctrl "); 
        if ( k->modifiers() &Qt::ShiftModifier ) text.append ("Shift "); 
        if ( k->modifiers() &Qt::AltModifier ) text.append ("Alt "); 
        if ( k->key() < 0x100 ) text.append (QChar (k->key())); 
        text.append (QString (" (0x%1)").arg (k->key(), 0, 16)); 
        setText (text); 
    } 
}; 

int main (int argc, char* argv[]) { 
    QApplication a (argc, argv); 
    MyWidget w; 
    w.show(); 
    return a.exec(); 
}