std::time_get::get_year, std::time_get::do_get_year

 

C++

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Regular expressions library (C++11)

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Localizations library

Locales and facets
locale
use_facet	has_facet
Character classification
isspace isblank (C++11) iscntrl isupper islower isalpha	isdigit ispunct isxdigit isalnum isprint isgraph
Conversions
toupper tolower	wstring_convert (C++11) wbuffer_convert (C++11)
Facet category base classes
ctype_base codecvt_base messages_base	time_base money_base
Facet categories
ctype ctype<char> codecvt collate messages time_get time_put	num_get num_put numpunct money_get money_put moneypunct
Locale-specific facets
ctype_byname ctype_byname<char> codecvt_byname messages_byname collate_byname	time_get_byname time_put_byname numpunct_byname moneypunct_byname
Code conversion facets
codecvt_utf8 (C++11) codecvt_utf16 (C++11)	codecvt_utf8_utf16 (C++11) codecvt_mode (C++11)
C locale
setlocale localeconv lconv	LC_ALL LC_COLLATE LC_CTYPE LC_MONETARY LC_NUMERIC LC_TIME

 

std::time_get

Member functions

time_get::time_get

time_get::~time_get

time_get::date_order time_get::do_date_order

time_get::get_time time_get::do_get_time

time_get::get_date time_get::do_get_date

time_get::get_weekday time_get::do_get_weekday

time_get::get_monthname time_get::do_get_monthname

time_get::get_year time_get::do_get_year

time_get::get time_get::do_get

 

Defined in header <locale>
public: iter_type do_get_year( iter_type s, iter_type end, std::ios_base& str,                        std::ios_base::iostate& err, std::tm* t) const;	(1)
protected: virtual iter_type do_get_year( iter_type s, iter_type end, std::ios_base& str,                                std::ios_base::iostate& err, std::tm* t) const;	(2)

1) public member function, calls the protected virtual member function do_get_year of the most derived class.

2) Reads successive characters from the sequence [beg, end) and parses out the year using some implementation-defined format. Depending on the locale, two-digit years may be accepted, and it is implementation-defined which century they belong to.

The parsed year is stored in the std::tm structure field t->tm_year.

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 year.

Notes

For two-digit input values, many implementations use the same parsing rules as the conversion specifier '%y' as used by std::get_time, time_get::get, and the POSIX function strptime(): two-digit integer is expected, the values in the range [69,99] results in values 1969 to 1999, range [00,68] results in 2000-2068. Four-digit inputs are typically accepted as-is.

If a parsing error is encountered, most implementations of this function leave *t unmodified.

Example

run this code

#include <iostream>
#include <locale>
#include <sstream>
#include <iterator>
 
void try_get_year(const std::string& s)
{
    std::cout << "Parsing the year 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_year(
            std::istreambuf_iterator<char>(str),
            std::istreambuf_iterator<char>(),
            str, err, &t
        );
    str.setstate(err);
    if(str) {
        std::cout << "Successfully parsed, year is " << 1900 + t.tm_year;
        if(ret != std::istreambuf_iterator<char>()) {
            std::cout << " Remaining content: ";
            std::copy(ret, std::istreambuf_iterator<char>(),
                      std::ostreambuf_iterator<char>(std::cout));
        } else {
            std::cout << " the input was fully consumed";
        }
    } else {
        std::cout << "Parse failed. Unparsed string: ";
        std::copy(ret, std::istreambuf_iterator<char>(),
                  std::ostreambuf_iterator<char>(std::cout));
    }
    std::cout << '\n';
}
int main()
{
    std::locale::global(std::locale("en_US.utf8"));
    try_get_year("13");
    try_get_year("2013");
 
    std::locale::global(std::locale("ja_JP.utf8"));
    try_get_year("2013年");
}

Possible output:

Parsing the year out of '13' in the locale en_US.utf8
Successfully parsed, year is 2013 the input was fully consumed
Parsing the year out of '2013' in the locale en_US.utf8
Successfully parsed, year is 2013 the input was fully consumed
Parsing the year out of '2013年' in the locale ja_JP.utf8
Successfully parsed, year is 2013 Remaining content: 年

See also

get_time (C++11)	parses a date/time value of specified format (function template)