def var f-curr-date-time as decimal format "zzz,zzz,zzz.999999" no-undo.
def var f-past-date-time as decimal format "zzz,zzz,zzz.999999" no-undo.
def var past-date as date no-undo.
def var past-time as integer no-undo.


function date-time-now returns decimal:
  return integer(today) + time / 86400.
end function.

function date-time-then returns decimal
  (input f-date as integer, input f-time as integer):
  return f-date + f-time / 86400.
end function.

function days-diff returns integer
  (input date-time-then as dec, input date-time-now as dec):
  return integer(truncate(date-time-now,0) - truncate(date-time-then,0)).
end function.

function time-diff returns integer
  (input date-time-then as dec, input date-time-now as dec):
  return integer((date-time-now - truncate(date-time-now,0)) * 86400)
    - integer((date-time-then - truncate(date-time-then,0)) * 86400).
end function.


past-date = today - 1.
past-time = TIME - 30.

f-curr-date-time = date-time-now().
f-past-date-time = date-time-then(integer(past-date), past-time).

display "curr date-time:" f-curr-date-time today time
          string(time,"hh:mm:ss") skip
        "past date-time:" f-past-date-time past-date past-time string(past-time,"hh:mm:ss") skip
        "days diff:" days-diff(f-past-date-time, f-curr-date-time) skip
        "time diff:" time-diff(f-past-date-time, f-curr-date-time)
  WITH NO-LABELS.

/* end of program */