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