Standard C++ LibraryCopyright 1996, Rogue Wave Software, Inc.

NAME

  num_put - Numeric formatting  facet for output.

SYNOPSIS

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

DESCRIPTION

  The num_put<charT,OutputIterator> template provides facilities for
  formatted output of numbers.  basic_ostream and all other input 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 AND DESTRUCTORS

  explicit num_put(size_t refs = 0)
     Construct 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
     had, if refs  is 1 then the object must be explicitly deleted; the
     locale will not do so.  In this case, the object can be maintained
     across the lifetime of multiple locales.

  ~num_put();  // virtual and protected
     Destroy 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 provide an interface to protected
  members.  Each public member xxx has a corresponding virtual protected
  member do_xxx.  All work is delagated 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, numget, numpunct, ctype

STANDARDS CONFORMANCE

  ANSI X3J16/ISO WG21 Joint C++ Committee



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