/in/foo.cc: In function 'int main()':
/in/foo.cc:83:11: error: invalid initialization of non-const reference of type 'complex&' from an rvalue of type 'complex'
  hhh.set (complex(p,q),i);
           ^~~~~~~~~~~~
/in/foo.cc:47:7: note:   initializing argument 1 of 'void complexarray::set(complex&, int)'
  void set(complex& c,int i)
       ^~~