/in/foo.cc: In member function 'int Date::is_leap()':
/in/foo.cc:32:20: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   if (y % 100 != 0 && y % 4 == 0 || y % 400 == 0)
       ~~~~~~~~~~~~~^~~~~~~~~~~~~
/in/foo.cc: In constructor 'DateTime::DateTime(int, int, int, int, int, int)':
/in/foo.cc:64:7: warning: 'DateTime::d' will be initialized after [-Wreorder]
  Date d;
       ^
/in/foo.cc:63:7: warning:   'Time DateTime::t' [-Wreorder]
  Time t;
       ^
/in/foo.cc:66:2: warning:   when initialized here [-Wreorder]
  DateTime(int y, int m, int d, int h, int mm, int s) :d(y, m, d), t(h, mm, s) {}
  ^~~~~~~~