#ifndef CELL_H#define CELL_H#include <qtable.h>#include <qvariant.h>class Cell : public QTableItem{public:    Cell(QTable *table, const QString &formula);    void setFormula(const QString &formula);    QString formula() const;    void setDirty();    QString text() const;    int alignment() const;private:    QVariant value() const;    QVariant evalExpression(const QString &str, int &pos) const;    QVariant evalTerm(const QString &str, int &pos) const;    QVariant evalFactor(const QString &str, int &pos) const;    QString formulaStr;    mutable QVariant cachedValue;    mutable bool cacheIsDirty;};#endif