/in/foo.cc: In function 'std::chrono::_V2::system_clock::time_point string_to_time_point(const string&)':
/in/foo.cc:12:11: error: 'get_time' was not declared in this scope
   12 |     ss >> get_time(&tm, "%Y-%m-%d");
      |           ^~~~~~~~
/in/foo.cc: In function 'int days_between(const string&, const string&)':
/in/foo.cc:21:42: error: 'days' is not a member of 'std::chrono'
   21 |     return chrono::duration_cast<chrono::days>(duration).count() + 1; // 包括起始和结束日期
      |                                          ^~~~
/in/foo.cc:21:42: error: 'days' is not a member of 'std::chrono'
/in/foo.cc:21:56: error: no matching function for call to 'duration_cast<<expression error> >(std::chrono::duration<long int, std::ratio<1, 1000000000> >&)'
   21 |     return chrono::duration_cast<chrono::days>(duration).count() + 1; // 包括起始和结束日期
      |                                                        ^
In file included from /in/foo.cc:2:
/usr/include/c++/9/chrono:191:7: note: candidate: 'template<class _ToDur, class _Rep, class _Period> constexpr std::chrono::__enable_if_is_duration<_ToDur> std::chrono::duration_cast(const std::chrono::duration<_Rep, _Period>&)'
  191 |       duration_cast(const duration<_Rep, _Period>& __d)
      |       ^~~~~~~~~~~~~
/usr/include/c++/9/chrono:191:7: note:   template argument deduction/substitution failed:
/in/foo.cc:21:56: error: template argument 1 is invalid
   21 |     return chrono::duration_cast<chrono::days>(duration).count() + 1; // 包括起始和结束日期
      |                                                        ^