foo.cc:98:11: error: ISO C++ forbids declaration of 'DataTime' with no type [-fpermissive]
   98 |  DataTime()
      |           ^
foo.cc: In member function 'int DateTime::DataTime()':
foo.cc:99:4: warning: no return statement in function returning non-void [-Wreturn-type]
   99 |  { }
      |    ^

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