table of contents
std::chrono::operator<<(std::chrono::year)(3) | C++ Standard Libary | std::chrono::operator<<(std::chrono::year)(3) |
NAME¶
std::chrono::operator<<(std::chrono::year) - std::chrono::operator<<(std::chrono::year)
Synopsis¶
Defined in header <chrono>
template< class CharT, class Traits >
std::basic_ostream<CharT, Traits>& (since C++20)
operator<<( std::basic_ostream<CharT, Traits>& os, const
std::chrono::year& y );
Forms a std::basic_string<CharT> s consisting of the year value stored
in y
formatted as a decimal number, left-padded with 0 to four digits if the
result would
otherwise be less than four digits. Then, if !y.ok(), append " is not a
valid year"
to the formatted string. Inserts that string into os.
Equivalent to
return os << (y.ok() ?
std::format(STATICALLY_WIDEN<CharT>("{:%Y}"), y) :
std::format(STATICALLY_WIDEN<CharT>("{:%Y} is not a valid
year"), y));
where STATICALLY_WIDEN<CharT>("...") is "..." if
CharT is char, and L"..." if CharT
is wchar_t.
Return value¶
os.
Example¶
// Run this code
#include <chrono>
#include <iostream>
int main()
{
constexpr std::chrono::year y1 {2020}, y2 {-020}, y3 {98304};
std::cout << y1 << '\n'
<< y2 << '\n'
<< y3 << '\n';
}
Possible output:¶
2020
-0016
-32768 is not a valid year
See also¶
format stores formatted representation of the arguments
(C++20) in a new string
(function template)
std::formatter<std::chrono::year> specialization of std::formatter that
formats a
(C++20) year according to the provided format
(class template specialization)
2022.07.31 | http://cppreference.com |