(* Compute Fibonacci numbers. *)

PROGRAM IS
  TYPE IARRAY IS ARRAY OF INTEGER;
  VAR N := 40;
  VAR I := 0;
  VAR fibs := IARRAY {N OF 0};
  VAR j,n := 0;
  
PROCEDURE init(a : IARRAY) IS
  VAR i : INTEGER := 0;
  BEGIN
    a[0] := 1;
    a[1] := 1;
    FOR i := 2 TO N - 1 DO
      a[i] := I;
    END;
  END;

PROCEDURE fib(i: INTEGER) : INTEGER IS
  BEGIN
   IF fibs[i] = I THEN
     fibs[i] := fib(i-2) + fib(i-1);
   END;
   RETURN fibs[i];
END;

BEGIN
  init(fibs);
  WRITE("Enter indices of eight Fibonacci numbers:");
  FOR j := 0 TO 7 DO
    READ(n);
    IF n > N THEN  (* A bug -- should be >= N *)
      WRITE("Maximum index is ", N);
    ELSE
      WRITE(n, " ", fib(n));
    END;
  END;
END;