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num_get
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num_get
num_getlocale::facet
- Summary
- Data Type and Member Function Indexes
- Synopsis
- Description
- Interface
- Types
- Constructor and Destructor
- Facet ID
- Public Member Functions
- Protected Member Functions
- Example
- See Also
Summary
Numeric formatting facet for input.
Data Type and Member Function Indexes
(exclusive of constructors and destructors)
Synopsis
#include <locale> template <class charT, class InputIterator > class num_get;
Description
The num_get provides facilities for formatted input of numbers. basic_istream and all other input-oriented streams use this facet to implement formatted numeric input.
Interface
template <class charT, class InputIterator = istreambuf_iterator<charT> >
class num_get : public locale::facet {
public:
typedef charT char_type;
typedef InputIterator iter_type;
explicit num_get(size_t refs = 0);
iter_type get(iter_type, iter_type, ios_base&,
ios_base::iostate&, bool&) const;
iter_type get(iter_type, iter_type, ios_base& ,
ios_base::iostate&, long&) const;
iter_type get(iter_type, iter_type, ios_base&,
ios_base::iostate&, unsigned short&) const;
iter_type get(iter_type, iter_type, ios_base&,
ios_base::iostate&, unsigned int&) const;
iter_type get(iter_type, iter_type, ios_base&,
ios_base::iostate&, unsigned long&) const;
iter_type get(iter_type, iter_type, ios_base&,
ios_base::iostate&, float&) const;
iter_type get(iter_type, iter_type, ios_base&,
ios_base::iostate&, double&) const;
iter_type get(iter_type, iter_type, ios_base&,
ios_base::iostate&, long double&) const;
static locale::id id;
protected:
~num_get(); // virtual
virtual iter_type do_get(iter_type, iter_type, ios_base&,
ios_base::iostate&, bool&) const;
virtual iter_type do_get(iter_type, iter_type, ios_base&,
ios_base::iostate&, long&) const;
virtual iter_type do_get(iter_type, iter_type, ios_base&,
ios_base::iostate&,
unsigned short&) const;
virtual iter_type do_get(iter_type, iter_type, ios_base&,
ios_base::iostate&,
unsigned int&) const;
virtual iter_type do_get(iter_type, iter_type, ios_base&,
ios_base::iostate&,
unsigned long&) const;
virtual iter_type do_get(iter_type, iter_type, ios_base&,
ios_base::iostate&, float&) const;
virtual iter_type do_get(iter_type, iter_type, ios_base&,
ios_base::iostate&, double&) const;
virtual iter_type do_get(iter_type, iter_type, ios_base&,
ios_base::iostate&,
long double&) const;
};
Types
char_type
Type of character the facet is instantiated on.
iter_type
Type of iterator used to scan the character buffer.
Constructor and Destructor
explicit num_get(size_t refs = 0)
Construct a num_get 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_get(); // 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_get facet provide 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 get function simply calls its protected cousin do_get.
iter_type
get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err, bool& v) const;
iter_type
get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err, long& v) const;
iter_type
get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err, unsigned short& v) const;
iter_type
get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err, unsigned int& v) const;
iter_type
get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err, unsigned long& v) const;
iter_type
get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err, float& v) const;
iter_type
get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err, double& v) const;
iter_type
get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err, long double& v) const;
Each of the eight overloads of the get function simply call the corresponding do_get function.
Protected Member Functions
virtual iter_type
do_get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err, bool& v) const;
virtual iter_type
do_get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err, long& v) const;
virtual iter_type
do_get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err,
unsigned short& v) const;
virtual iter_type
do_get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err,
unsigned int& v) const;
virtual iter_type
do_get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err,
unsigned long& v) const;
virtual iter_type
do_get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err, float& v) const;
virtual iter_type
do_get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& err, double& v) const;
virtual iter_type
do_get(iter_type in, iter_type end, ios_base& io,
ios_base::iostate& long double& v) const;
The eight overloads of the do_get member function all take a sequence of characters [int,end), and extract a numeric value. The numeric value is returned in v. The io argument is used to obtain formatting information and the err argument is used to set error conditions in a calling stream.
Example
//
// numget.cpp
//
#include <sstream>
int main ()
{
using namespace std;
typedef istreambuf_iterator<char,char_traits<char> > iter_type;
locale loc;
ios_base::iostate state;
bool bval = false;
long lval = 0L;
long double ldval = 0.0;
iter_type end;
// Get a num_get facet
const num_get<char,iter_type>& tg =
#ifndef _RWSTD_NO_TEMPLATE_ON_RETURN_TYPE
use_facet<num_get<char,iter_type> >(loc);
#else
use_facet(loc,(num_get<char,iter_type>*)0);
#endif
{
// Build an istringstream from the buffer and construct
// beginning and ending iterators on it.
istringstream ins("true");
iter_type begin(ins);
// Get a bool value
tg.get(begin,end,ins,state,bval);
}
cout << bval << endl;
{
// Get a long value
istringstream ins("2422235");
iter_type begin(ins);
tg.get(begin,end,ins,state,lval);
}
cout << lval << endl;
{
// Get a long double value
istringstream ins("32324342.98908");
iter_type begin(ins);
tg.get(begin,end,ins,state,ldval);
}
cout << ldval << endl;
return 0;
}
See Also
locale, facets, num_put, numpunct, ctype
©Copyright 1996, Rogue Wave Software, Inc.
