CARD FUNC Factorial(INT n BYTE POINTER err)
  CARD i,res

  IF n<0 THEN
    err^=1 RETURN (0)
  ELSEIF n>8 THEN
    err^=2 RETURN (0)
  FI

  res=1
  FOR i=2 TO n
  DO
    res=res*i
  OD

  err^=0
RETURN (res)

PROC Main()
  INT i,f
  BYTE err

  FOR i=-2 TO 10
  DO
    f=Factorial(i,@err)

    IF err=0 THEN
      PrintF("%I!=%U%E",i,f)
    ELSEIF err=1 THEN
      PrintF("%I is negative value%E",i)
    ELSE
      PrintF("%I! is to big%E",i)
    FI
  OD
RETURN