std::time_get::get_date, std::time_get::do_get_date - cppreference.com

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# std::time_get::get_date, std::time_get::do_get_date

From cppreference.com
< cpp‎ | locale‎ | time get

Defined in header `<locale>` |  |
public: iter_type get_date( iter_type beg, iter_type end, std::ios_base& str, std::ios_base::iostate& err, std::tm* t ) const; | (1) |
protected: virtual iter_type do_get_date( iter_type beg, 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_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 date_order() | (since C++11)

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`.

### [edit] 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

### [edit] Return value

Iterator pointing one past the last character in `[beg, end)` that was recognized as a part of a valid date.

### [edit] 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.

### [edit] 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(
                std::istreambuf_iterator<char>(str),
                std::istreambuf_iterator<char>(),
                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::istreambuf_iterator<char>(),
                      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

### [edit] See also

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

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