Movatterモバイル変換


[0]ホーム

URL:


cppreference.com
Namespaces
Variants
    Actions

      std::chrono::month::operator+=,std::chrono::month::operator-=

      From cppreference.com
      <cpp‎ |chrono‎ |month
       
       
      Date and time library
       
       
      constexprstd::chrono::month& operator+=(conststd::chrono::months& m)noexcept;
      (1)(since C++20)
      constexprstd::chrono::month& operator-=(conststd::chrono::months& m)noexcept;
      (2)(since C++20)

      Adds or subtractsm.count() from the month value, reducing the result modulo 12 to an integer in the range[112].

      1) Performs*this=*this+ m;.
      2) Performs*this=*this- m;.

      Contents

      [edit]Return value

      A reference to thismonth after modification.

      [edit]Notes

      After a call to one of these functions,ok() is alwaystrue if no overflow occurred during the operation.

      [edit]Example

      Run this code
      #include <chrono>#include <iostream> int main(){std::cout<<std::boolalpha; std::chrono::month m{6};    m+=std::chrono::months(2);std::cout<<(m==std::chrono::month(8))<<' '<<(m==std::chrono::August)<<' ';     m-=std::chrono::months(3);std::cout<<(m==std::chrono::month(5))<<' '<<(m==std::chrono::May)<<' ';     m=std::chrono::October;    m+=std::chrono::months{8};// ((10 += 8 == 18) % 12) == 6;std::cout<<(m==std::chrono::June)<<' ';     m-=std::chrono::months{std::chrono::December-std::chrono::February};// -= 10// (6 -= 10) == -4; -4 % 12 == (12 - 4) == 8std::cout<<(m==std::chrono::August)<<'\n';}

      Output:

      true true true true true true

      [edit]See also

      increments or decrements the month
      (public member function)[edit]
      performs arithmetic onmonths
      (function)[edit]
      Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/chrono/month/operator_arith&oldid=157580"

      [8]ページ先頭

      ©2009-2026 Movatter.jp