/in/foo.cc: In function 'int main()':
/in/foo.cc:83:17: error: no matching function for call to 'Array::insert(int&)'
   83 |         a.insert(k);
      |         ~~~~~~~~^~~
/in/foo.cc:55:14: note: candidate: 'void Array::insert(int, int&)'
   55 |         void insert(int pos, int& value)
      |              ^~~~~~
/in/foo.cc:55:14: note:   candidate expects 2 arguments, 1 provided