num_put(3C++) - num_put(3C++)
Standard C++ Library Copyright 1998, Rogue Wave Software, Inc.
NAMEnum_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 pro‐
tected members. Each public member xxx has a corresponding virtual pro‐
tected 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_typeput(iter_type s, ios_base& io, char_type fill, long v)
const;
iter_typeput(iter_type s, ios_base& io, char_type fill,
unsigned long v) const;
iter_typeput(iter_type s, ios_base& io, char_type fill, double v)
const;
iter_typeput(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 correspond‐
ing do_put function.
PROTECTED MEMBER FUNCTIONSvirtual iter_typedo_put(iter_type s, ios_base& io,
char_type fill, bool v) const;
virtual iter_typedo_put(iter_type s, ios_base& io,
char_type fill, long v) const;
virtual iter_typedo_put(iter_type s, ios_base& io,
char_type fill,unsigned long) const;
virtual iter_typedo_put(iter_type s, ios_base& io,
char_type fill, double v) const;
virtual iter_typedo_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 char‐
acter string is output through the s argument to the function. The io argu‐
ment 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
Rogue Wave Software 02 Apr 1998 num_put(3C++)
