#ifndef CALCULATOR_H#define CALCULATOR_H#include <QDialog>class QLineEdit;class Button;class Digital : public QDialog{    Q_OBJECTpublic:    Digital(QWidget *parent = 0);protected:    bool eventFilter(QObject *target, QEvent *event);private slots:    void digitClicked();private:    Button *createButton(const QString &text, const QColor &color,                         const char *member);    QLineEdit *display;    enum { NumDigitButtons = 10 };    Button *digitButtons[NumDigitButtons];};#endif