ZABAP101_RECURSION - with error

gistfile1.txt

*&---------------------------------------------------------------------*
*& Report  ZABAP101_RECURSION
*&
*&---------------------------------------------------------------------*
*&
*&
*&---------------------------------------------------------------------*

REPORT  zabap101_recursion.

*----------------------------------------------------------------------*
*       CLASS lcl_math DEFINITION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS lcl_math DEFINITION.

  PUBLIC SECTION.

    METHODS execute_exponentiation
              IMPORTING
                base TYPE i
                expoent TYPE i
              RETURNING value(re_power) TYPE i.

  PRIVATE SECTION.

    DATA: interaction TYPE i.

ENDCLASS.                    "lcl_math DEFINITION


*----------------------------------------------------------------------*
*       CLASS lcl_math IMPLEMENTATION
*----------------------------------------------------------------------*
*
*----------------------------------------------------------------------*
CLASS lcl_math IMPLEMENTATION.

  METHOD execute_exponentiation.
    ADD 1 TO interaction.
    IF interaction <= expoent.
      re_power = re_power * me->execute_exponentiation( base = base
                                                        expoent = expoent ).
    ELSE.
      CLEAR interaction.
    ENDIF.
  ENDMETHOD.                    "execute_exponentiation

ENDCLASS.                    "lcl_math IMPLEMENTATION

DATA: r_exp   TYPE REF TO lcl_math,
      v_power TYPE i.

PARAMETERS: p_base TYPE i DEFAULT 2,
            p_exp  TYPE i DEFAULT 3.

INITIALIZATION.

  CREATE OBJECT r_exp.

START-OF-SELECTION.

  v_power = r_exp->execute_exponentiation( base = p_base
                                           expoent = p_exp ).

  WRITE: / 'Power: ', v_power.