program setExample1 (input, output);

const String_Size = 30;

type Upper_Set = set of 'A'..'Z';

var Data_Set    : Upper_Set;
    Storage     : string[String_Size];
    Index       : 1..String_Size;
    Print_Group : string[26];

begin  (* main program *)
   Data_Set := [];
   Print_Group := '';
   Storage := 'This Is A Set Test.';

   for Index := 1 to Length(Storage) do begin
      if Storage[Index] in ['A'..'Z'] then begin
         if Storage[Index] in Data_Set then
            Writeln(Index:4,'   ',Storage[Index],
                         ' is already in the set')
         else begin
            Data_Set := Data_Set + [Storage[Index]];
            Print_Group := Print_Group + Storage[Index];
            Writeln(Index:4,'   ',Storage[Index],
                         ' added to group, complete group = ',
                         Print_Group);
         end;
      end
      else
         Writeln(Index:4,'   ',Storage[Index],
                       ' is not an upper case letter');
   end;
end.  (* of main program *)


{ Result of execution

   1   T added to group, complete group = T
   2   h is not an upper case letter
   3   i is not an upper case letter
   4   s is not an upper case letter
   5     is not an upper case letter
   6   I added to group, complete group = TI
   7   s is not an upper case letter
   8     is not an upper case letter
   9   A added to group, complete group = TIA
  10     is not an upper case letter
  11   S added to group, complete group = TIAS
  12   e is not an upper case letter
  13   t is not an upper case letter
  14     is not an upper case letter
  15   T is already in the set
  16   e is not an upper case letter
  17   s is not an upper case letter
  18   t is not an upper case letter
  19   . is not an upper case letter

}