MODULE DigitalRoot EXPORTS Main;

IMPORT IO;
FROM Fmt IMPORT F,LongInt;

TYPE
     Root = RECORD persistence,R:LONGINT END;

VAR
     R:Root;
     Arr:ARRAY[0..3] OF LONGINT := ARRAY OF LONGINT{627615L,
						    39390L,
						    588225L,
						    393900588225L};

PROCEDURE DigitalRoot(InRoot,Base:LONGINT):Root =
VAR
     r,persistence,Num:LONGINT;
BEGIN
     r := ABS(InRoot);
     persistence := 0L;
     WHILE r >= Base DO
	  Num := r;
	  r := 0L;
	  WHILE Num # 0L DO
	       r := r + (Num MOD Base);
	       Num := Num DIV Base;
	  END;
	  INC(persistence);
     END;
     RETURN Root{persistence, r};
END DigitalRoot;

BEGIN
     FOR I := FIRST(Arr) TO LAST(Arr) DO
       R := DigitalRoot(Arr[I], 10L);
       IO.Put(F(LongInt(Arr[I]) &
       " has additive persistence %s and digital root of %s\n",
		LongInt(R.persistence),
		LongInt(R.R)));
     END;
END DigitalRoot.