ctype<char>

class ctype<char> : public locale::facet, public ctype_base {
public:
    typedef char char_type;
    explicit ctype(const mask *tab = 0, bool del = false,
        size_t refs = 0);
    bool is(mask msk, char ch) const;
    const char *is(const char *first, const char *last,
        mask *dst) const;
    const char *scan_is(mask msk,
        const char *first, const char *last) const;
    const char *scan_not(mask msk,
        const char *first, const char *last) const;
    char toupper(char ch) const;
    const char *toupper(char *first, char *last) const;
    char tolower(char ch) const;
    const char *tolower(char *first, char *last) const;
    char widen(char ch) const;
    const char *widen(char *first, char *last, char *dst) const;
    char narrow(char ch, char dflt) const;
    const char *narrow(const char *first, const char *last,
        char dflt, char *dst) const;
    static locale::id id;
protected:
    ~ctype();
    virtual char do_toupper(char ch) const;
    virtual const char *do_toupper(char *first, char *last) const;
    virtual char do_tolower(char ch) const;
    virtual const char *do_tolower(char *first, char *last) const;
    const mask *table() const throw();
    static const mask *classic_table() const throw();
    static const size_t table_size;
    };

The class is an explicit specialization of template class ctype for type char. Hence, it describes an object that can serve as a locale facet, to characterize various properties of a "character" (element) of type char. The explicit specialization differs from the template class in several ways:

• Its sole public constructor lets you specify tab, the ctype mask table, and del, the Boolean object that is true if the array should be deleted when the ctype<char> object is destroyed -- as well as the usual reference-count parameter refs.
• The protected member function table() returns the stored ctype mask table.
• The static member object table_size specifies the minimum number of elements in a ctype mask table.
• The protected static member function classic_table() returns the ctype mask table appropriate to the "C" locale.
• There are no protected virtual member functions do_is, do_narrow, do_scan_is, do_scan_not, or do_widen. The corresponding public member functions perform the equivalent operations themselves.
• The member functions narrow and widen simply copy elements unaltered.