/in/foo.cc: In function 'int main()':
/in/foo.cc:56:35: error: invalid use of non-static member function 'T Array<T>::getsum() [with T = double]'
  cout << fixed << setprecision(2) << b.getsum << endl;
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
/in/foo.cc:34:3: note: declared here
 T Array<T>::getsum()
   ^~~~~~~~
/in/foo.cc: In instantiation of 'T Array<T>::getsum() [with T = int]':
/in/foo.cc:55:19:   required from here
/in/foo.cc:39:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^