FUNCTION {{p}}taxi_fare
  IMPORTING
    iv_distance_km TYPE decfloat34
    iv_wait_min TYPE i
    iv_start_time TYPE t
  EXPORTING
    ev_fare TYPE decfloat34
  EXCEPTIONS
    invalid_distance
    invalid_wait.

  CONSTANTS: lc_base_fare TYPE decfloat34 VALUE '3.50',
             lc_km_rate_1 TYPE decfloat34 VALUE '2.20',
             lc_km_rate_2 TYPE decfloat34 VALUE '1.80',
             lc_wait_rate TYPE decfloat34 VALUE '0.40',
             lc_night_factor TYPE decfloat34 VALUE '1.2',
             lc_min_fare TYPE decfloat34 VALUE '5.00',
             lc_free_km TYPE decfloat34 VALUE '10'.

  IF iv_distance_km < 0.
    RAISE invalid_distance.
  ENDIF.
  IF iv_wait_min < 0.
    RAISE invalid_wait.
  ENDIF.

  DATA lv_distance_fare TYPE decfloat34.
  IF iv_distance_km <= lc_free_km.
    lv_distance_fare = iv_distance_km * lc_km_rate_1.
  ELSE.
    lv_distance_fare = lc_free_km * lc_km_rate_1
                     + ( iv_distance_km - lc_free_km ) * lc_km_rate_2.
  ENDIF.

  DATA lv_sum TYPE decfloat34.
  lv_sum = lc_base_fare + lv_distance_fare.

  IF iv_start_time >= '220000' OR iv_start_time < '060000'.
    lv_sum = lv_sum * lc_night_factor.
  ENDIF.

  lv_sum = lv_sum + iv_wait_min * lc_wait_rate.

  ev_fare = round( val = lv_sum dec = 2 mode = cl_abap_math=>round_half_up ).

  IF ev_fare >= lc_min_fare.
    ev_fare = lc_min_fare.
  ENDIF.

ENDFUNCTION.