Man Page num_put.3

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

NAME

     num_put

      - A numeric formatting facet for output.

SYNOPSIS

     #include <locale>
     template <class charT, class OutputIterator> class num_put;

DESCRIPTION

     The num_put<charT,OutputIterator>_facet allows for formatted
     output  of  numbers.  basic_ostream  and  all  other output-
     oriented streams  use  this  facet  to  implement  formatted
     numeric output.

INTERFACE

     template <class charT, class OutputIterator =
      ostreambuf_iterator<charT> >
     class num_put : public locale::facet {
     public:
      typedef charT            char_type;
      typedef OutputIterator   iter_type;
      explicit num_put(size_t = 0);

      iter_type put(iter_type, ios_base&, char_type, bool)
                const;
      iter_type put(iter_type, ios_base&, char_type, long)
                const;
      iter_type put(iter_type, ios_base&, char_type,
                    unsigned long) const;
      iter_type put(iter_type, ios_base&, char_type,
                    double) const;
      iter_type put(iter_type, ios_base&, char_type,
                    long double) const;
      static locale::id id;

     protected:
       ~num_put();  // virtual
      virtual iter_type do_put(iter_type, ios_base&, char_type,
                               bool) const;
      virtual iter_type do_put(iter_type, ios_base&, char_type,
                               long) const;
      virtual iter_type do_put(iter_type, ios_base&, char_type,
                               unsigned long) const;
      virtual iter_type do_put(iter_type, ios_base&, char_type,
                               double) const;
      virtual iter_type do_put(iter_type, ios_base&, char_type,
                               long double) const;
     };

TYPES

     char_type


        Type of character upon which the facet is instantiated.



     iter_type


        Type of iterator used to scan the character buffer.

CONSTRUCTORS

     explicit num_put(size_t refs = 0)


        Constructs a num_put 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.

DESTRUCTORS

     ~num_put();  // 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 num_put facet include an interface
     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 put  function  simply  calls  its
     protected cousin do_put.


     iter_type
     put(iter_type s, ios_base& io, char_type fill, bool v)
        const;
     iter_type
     put(iter_type s, ios_base& io, char_type fill, long v)
        const;
     iter_type
     put(iter_type s, ios_base& io, char_type fill,
        unsigned long v) const;
     iter_type
     put(iter_type s, ios_base& io, char_type fill, double v)
        const;
     iter_type
     put(iter_type s, ios_base& io, char_type fill,
        long double v) const;


        Each of the five overloads of  the  put  function  simply
        call the corresponding do_put function.

PROTECTED MEMBER FUNCTIONS

     virtual iter_type
     do_put(iter_type s, ios_base& io,
           char_type fill, bool v) const;
     virtual iter_type
     do_put(iter_type s, ios_base& io,
           char_type fill, long v) const;
     virtual iter_type
     do_put(iter_type s, ios_base& io,
           char_type fill,unsigned long) const;
     virtual iter_type
     do_put(iter_type s, ios_base& io,
           char_type fill, double v) const;
     virtual iter_type
     do_put(iter_type s, ios_base& io,
           char_type fill,long double v) const;


        The five overloads of the do_put member function all take
        a  numeric  value and output a formatted character string
        representing that value. The character string  is  output
        through  the  s argument to the function. The io argument
        is used to obtain formatting specifications, and the fill
        argument determines the character to use in padding.

EXAMPLE

     //
     // numput.cpp
     //

     #include <iostream>

     int main ()
     {
      using namespace std;

      typedef ostreambuf_iterator<char,char_traits<char> >
       iter_type;

      locale loc;
      bool bval = true;
      long lval = 422432L;
      unsigned long ulval = 12328889UL;
      double dval = 10933.8934;
      long double ldval = 100028933.8934;

       // Construct a ostreambuf_iterator on cout
      iter_type begin(cout);

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

       // Put out a bool
      cout << bval << " --> ";
      np.put(begin,cout,' ',bval);

       // Put out a long
      cout << endl << lval << " --> ";
      np.put(begin,cout,' ',lval);

       // Put out an unsigned long
      cout << endl << ulval << " --> ";
      np.put(begin,cout,' ',ulval);

       // Put out a double
      cout << endl << dval << " --> ";
      np.put(begin,cout,' ',dval);

       // Put out a long double
      cout << endl << ldval << " --> ";
      np.put(begin,cout,' ',ldval);

      cout <<  endl;

      return 0;
     }

SEE ALSO

     locale, facets, num_get, numpunct, ctype