table of contents
std::time_get::get_date,std::time_get::do_get_date(3) | C++ Standard Libary | std::time_get::get_date,std::time_get::do_get_date(3) |
NAME¶
std::time_get::get_date,std::time_get::do_get_date - std::time_get::get_date,std::time_get::do_get_date
Synopsis¶
Defined in header <locale>
public:
iter_type get_date( iter_type beg, iter_type end, std::ios_base& str,
(1)
std::ios_base::iostate& err, std::tm* t ) const;
protected:
virtual iter_type do_get_date( iter_type beg, iter_type end,
std::ios_base& (2)
str,
std::ios_base::iostate& err, std::tm* t ) const;
1) Public member function, calls the protected virtual member function
do_get_date()
of the most derived class.
2) Reads successive characters from the sequence [beg, end) and parses out
the
calendar date value using the default format expected by this locale, which
is the
same format as
"%x" (until C++11)
"%d/%m/%y", "%m/%d/%y", "%y/%m/%d", and
"%y/%d/%m", depending on (since C++11)
date_order()
as used by the functions std::get_time(), get(), and the POSIX function
strptime()
The parsed date is stored in the corresponding fields of the std::tm
structure
pointed to by the argument t.
If the end iterator is reached before a valid date is read, the function sets
std::ios_base::eofbit in err. If a parsing error is encountered, the function
sets
std::ios_base::failbit in err.
Parameters¶
beg - iterator designating the start of the sequence to parse
end - one past the end iterator for the sequence to parse
str - a stream object that this function uses to obtain locale facets when
needed,
e.g. std::ctype to skip whitespace or std::collate to compare strings
err - stream error flags object that is modified by this function to indicate
errors
t - pointer to the std::tm object that will hold the result of this function
call
Return value¶
Iterator pointing one past the last character in [beg, end) that
was recognized as a
part of a valid date.
Notes¶
For the alphabetic components of the default date format (if
any), this function is
usually case-insensitive.
If a parsing error is encountered, most implementations of this function
leave *t
unmodified.
The implementation may support other date formats besides the ones required
by the
standard.
Example¶
// Run this code
#include <iostream>
#include <locale>
#include <sstream>
#include <iterator>
#include <ctime>
void try_get_date(const std::string& s)
{
std::cout << "Parsing the date out of '" << s <<
"' in the locale " << std::locale().name() << '\n';
std::istringstream str(s);
std::ios_base::iostate err = std::ios_base::goodbit;
std::tm t;
std::istreambuf_iterator<char> ret =
std::use_facet<std::time_get<char>>(str.getloc()).get_date(
{str}, {}, str, err, &t
);
str.setstate(err);
if(str) {
std::cout << "Day: " << t.tm_mday << ' '
<< "Month: " << t.tm_mon + 1 << ' '
<< "Year: " << t.tm_year + 1900 << '\n';
} else {
std::cout << "Parse failed. Unparsed string: ";
std::copy(ret, {}, std::ostreambuf_iterator<char>(std::cout));
std::cout << '\n';
}
}
int main()
{
std::locale::global(std::locale("en_US.utf8"));
try_get_date("02/01/2013");
try_get_date("02-01-2013");
std::locale::global(std::locale("ja_JP.utf8"));
try_get_date("2013年02月01日");
}
Output:¶
Parsing the date out of '02/01/2013' in the locale en_US.utf8
Day: 1 Month: 2 Year: 2013
Parsing the date out of '02-01-2013' in the locale en_US.utf8
Parse failed. Unparsed string: -01-2013
Parsing the date out of '2013年02月01日' in the locale
ja_JP.utf8
Day: 1 Month: 2 Year: 2013
See also¶
get_time parses a date/time value of specified format
(C++11) (function template)
2022.07.31 | http://cppreference.com |