/in/foo.cc: In constructor 'SeqList::SeqList()':
/in/foo.cc:9:14: error: 'length' was not declared in this scope
  SeqList() { length = 0; }
              ^~~~~~
/in/foo.cc: In member function 'void SeqList::Output()':
/in/foo.cc:25:22: error: 'length' was not declared in this scope
  for (int j = 0; j < length; j++)
                      ^~~~~~
/in/foo.cc: In member function 'void SeqList::Merge(SeqList&, SeqList&)':
/in/foo.cc:43:16: error: 'class SeqList' has no member named 'length'
   while (i < L.length)
                ^~~~~~