numpunct(3C++)

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

};

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 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 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 particular 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 unlimited. 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;

}

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