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                       Standard C++ Library
             Copyright 1998, Rogue Wave Software, Inc.


NAME
     numpunct, numpunct_byname

      - A numeric punctuation facet.



SYNOPSIS
     #include <locale>
     template <class charT>  class numpunct;
     template <class charT>  class numpunct_byname;



DESCRIPTION
     The  numpunct<charT>_facet  specifies  numeric  punctuation.
     numpunct   is   used   with   the   "C"  locale,  while  the
     numpunct_byname facet is used with named locales.

     Both num_put and num_get make use of this facet.



INTERFACE
     template <class charT>
     class numpunct : public locale::facet {
     public:
      typedef charT               char_type;
      typedef basic_string<charT> string_type;
      explicit numpunct(size_t refs = 0);
      char_type    decimal_point()   const;
      char_type    thousands_sep()   const;
      string       grouping()        const;
      string_type  truename()        const;
      string_type  falsename()       const;
      static locale::id id;
     protected:
       ~numpunct();  // virtual
      virtual char_type    do_decimal_point() const;
      virtual char_type    do_thousands_sep() const;
      virtual string       do_grouping()      const;
      virtual string_type  do_truename()     const;  // for bool
      virtual string_type  do_falsename()    const;  // for bool
     };

     template <class charT>
     class numpunct_byname : public numpunct<charT> {
     public:
      explicit numpunct_byname(const char*, size_t refs = 0);
     protected:
       ~numpunct_byname();  // virtual
      virtual char_type    do_decimal_point() const;
      virtual char_type    do_thousands_sep() const;
      virtual string       do_grouping()      const;
      virtual string_type  do_truename()     const;  // for bool
      virtual string_type  do_falsename()    const;  // for bool
     };



TYPES
     char_type


        Type of character upon which the facet is instantiated.



     string_type


        Type of character string returned by member functions.



CONSTRUCTORS
     explicit numpunct(size_t refs = 0)


        Constructs a numpunct facet. If the refs argument  is  0,
        then  destruction  of  the  object  is  delegated  to the
        locale, or locales, containing it. This allows  the  user
        to  ignore lifetime management issues. On the other hand,
        if refs is 1, then the object must be explicitly deleted;
        the  locale  does not do so. In this case, the object can
        be maintained across the lifetime of multiple locales.



     explicit numpunct_byname(const char* name,
             size_t refs = 0);


        Constructs a numpunct_byname facet. Uses the named locale
        specified  by the name argument. The refs argument serves
        the same purpose as it does for the numpunct constructor.



DESTRUCTORS
     ~numpunct();  // virtual and protected
     ~numpunct_byname();  // virtual and protected


        Destroys the facet.



FACET ID
     static locale::id id;



        Unique identifier for this type of facet.



PUBLIC MEMBER FUNCTIONS
     The public members of the numpunct facet include  an  inter-
     face  to  protected  members.  Each  public member xxx has a
     corresponding virtual protected member do_xxx. All  work  is
     delegated  to  these  protected members.   For instance, the
     long version of the public grouping  function  simply  calls
     its protected cousin do_grouping.


     char_type    decimal_point()   const;
     string_type  falsename()       const;
     string       grouping()        const;
     char_type    thousands_sep()   const;
     string_type  truename()        const;


        Each of these public member functions xxx simply call the
        corresponding protected do_xxx function.



PROTECTED MEMBER FUNCTIONS
     virtual char_type
     do_decimal_point() const;


        Returns the decimal  radix  separator.  numpunct  returns
        `.'.



     virtual string_type
     do_falsename()     const;  // for bool
     virtual string_type
     do_truename()      const;  // for bool


        Returns a string containing true or false.



     virtual string
     do_grouping()      const;


        Returns a string in which each character is  used  as  an
        integer value to represent the number of digits in a par-
        ticular grouping, starting with the  rightmost  group.  A
        group  is  simply  the  digits between adjacent thousands
        separators. Each group at a position larger than the size
        of  the string gets the same value as the last element in
        the string. If a value is less than or equal to zero,  or
        equal  to CHAR_MAX, then the size of that group is unlim-
        ited. numpunct returns an  empty  string,  indicating  no
        grouping.



     virtual char_type
     do_thousands_sep() const;


        Returns  the  decimal  digit  group  separator.  numpunct
        returns `,'.



EXAMPLE
     //
     // numpunct.cpp
     //
     #include <iostream>

     int main ()
     {
      using namespace std;
      locale loc;

       // Get a numpunct facet
      const numpunct<char>& np =
     #ifndef _RWSTD_NO_TEMPLATE_ON_RETURN_TYPE
      use_facet<numpunct<char> >(loc);
     #else
      use_facet(loc,(numpunct<char>*)0);
     #endif

      cout << "Decimal point       = "
            << np.decimal_point() << endl;
      cout << "Thousands separator = "
            << np.thousands_sep() << endl;
      cout << "True name           = "
            << np.truename() << endl;
      cout << "False name          = "
            << np.falsename() << endl;

      return 0;
     }



SEE ALSO
     locale, facets, num_put, num_get, ctype

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