// sales.h  -- exceptions and inheritance
#include <stdexcept>
#include <cstring>

class Sales
{
public:
    enum {MONTHS = 12};   // could be a static const
    class bad_index : public std::logic_error
    {
    private:
        int bi;  // bad index value
    public:
        explicit bad_index(int ix,
            const char * s = "Index error in Sales object\n");
        int bi_val() const {return bi;}
    };
    explicit Sales(int yy = 0);
    Sales(int yy, const double * gr, int n);
    virtual ~Sales() { }
    int Year() const { return year; }
    virtual double operator[](int i) const throw(std::logic_error);
    virtual double & operator[](int i) throw(std::logic_error);
private:
    double gross[MONTHS];
    int year;
};

class LabeledSales : public Sales
{
  public:
    static const int STRLEN = 50;  // could be an enum
    class nbad_index : public Sales::bad_index
    {
    private:
        char lbl[STRLEN];
    public:
        nbad_index(const char * lb, int ix,
           const char * s = "Index error in LabeledSales object\n");
        const char * label_val() {return lbl;}
    };
    explicit LabeledSales(const char * lb = "none", int yy = 0);
    LabeledSales(const char * lb, int yy, const double * gr, int n);
    virtual ~LabeledSales() { }
    const char * Label() const {return label;}
    virtual double operator[](int i) const throw(std::logic_error);
    virtual double & operator[](int i) throw(std::logic_error);
private:
    char label[STRLEN];
};