is this a type of initialization? the constructor ButtonWidget(int widgets) seems doesnt initialize int widget. could anyone explain it in detail=? thank you.
I donot understand the code in buttonwidget.cpp
Qt Code: 
  1. //buttonwidget.cpp
  2. ButtonWidget::ButtonWidget( int widgets )
  3.  : QWidget()
  4. {
  5.   QVBoxLayout *vbox = new QVBoxLayout();
  6.  
  7.   if ( widgets & ButtonWidget::ComboBoxes )
  8.     vbox->addWidget( comboBoxes() );
  9.  
  10.   if ( widgets & ButtonWidget::SpinBoxes )
  11.     vbox->addWidget( spinBoxes( widgets & ButtonWidget::SpinBoxexUpdateButton ) );
  12.  
  13.   if ( widgets & ButtonWidget::CheckBoxes )
  14.     vbox->addWidget( checkBoxes() );
  15.  
  16.   if ( widgets & ButtonWidget::ParetoBoxes )
  17.     vbox->addWidget( paretoBoxes() );
  18.  
  19.   if ( widgets & ButtonWidget::MarknDiffBoxes )
  20.     vbox->addWidget( markndiffBoxes() );
  21.  
  22.   vbox->addStretch();
  23.  
  24.   setLayout(vbox);
  25. }
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Qt Code: 
  1. //buttonwidget.h
  2. ........
  3. class ButtonWidget : public QWidget
  4. {
  5.   Q_OBJECT
  6.  
  7.   public:
  8.     enum Widgets
  9.     {
  10.       ComboBoxes = 1,
  11.       SpinBoxes = 2,
  12.       SpinBoxexUpdateButton = 4,
  13.       CheckBoxes = 8,
  14.       ParetoBoxes = 16,
  15.       MarknDiffBoxes = 32
  16.     };
  17.  
  18.     ButtonWidget( int widgets );
  19.     ~ButtonWidget();
  20. .........
  21.  private:
  22.     QGroupBox* comboBoxes();
  23.     QGroupBox* spinBoxes( bool updateButton );
  24.     QGroupBox* checkBoxes();
  25.     QGroupBox* paretoBoxes();
  26.     QGroupBox* markndiffBoxes();
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I just know the initialization as below. What kind of initialization is it in button.cpp?
Qt Code: 
  1. class Something
  2. 02    {
  3. 03    private:
  4. 04        int m_nValue;
  5. 05        double m_dValue;
  6. 06        int *m_pnValue;
  7. 07     
  8. 08    public:
  9. 09        Something()
  10. 10        {
  11. 11            m_nValue = 0;
  12. 12            m_dValue = 0.0;
  13. 13            m_pnValue = 0;
  14. 14        }
  15. 15    };
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