ABAP如何获取当前月的第一天和最后一天

直接上Example：

IF ip_loaddate_from IS INITIAL AND ip_loaddate_to IS INITIAL.
 CONCATENATE sy-datum(6) ‘01’ INTO r_loaddate-low. ”获取当前月的第一天
 CALL FUNCTION ‘BKK_GET_MONTH_LASTDAY’ ”获取当前月的最后一天
 EXPORTING
 i_date = sy-datum
 IMPORTING
 e_date = r_loaddate-high.
 r_loaddate-sign = ‘I’.
 r_loaddate-option = ‘BT’.
 APPEND r_loaddate.
 ENDIF.获取一个月的最后一天不需要自己写方法，可以直接调用了bkk_get_month_lastday这个function，这个function还处理好闰年闰月的问题，函数内容如下：
function bkk_get_month_lastday.“Determine Last Day of Month
 *”----------------------------------------------------------------------
"“Lokale Schnittstelle:
 *” IMPORTING
 *" VALUE(I_DATE) LIKE SY-DATUM
 *" EXPORTING
 *" VALUE(E_DATE) LIKE SY-DATUM
 *"----------------------------------------------------------------------
 data: check_year_1 type p.
 data: check_year_2 type p.e_date(4) = i_date(4).
 e_date+4(2) = i_date+4(2).if i_date+4(2) = ‘01’
 or i_date+4(2) = ‘03’
 or i_date+4(2) = ‘05’
 or i_date+4(2) = ‘07’
 or i_date+4(2) = ‘08’
 or i_date+4(2) = ‘10’
 or i_date+4(2) = ‘12’.
 e_date+6(2) = ‘31’. " 31 days per monthelseif i_date+4(2) = ‘04’
 or i_date+4(2) = ‘06’
 or i_date+4(2) = ‘09’
 or i_date+4(2) = ‘11’.
 e_date+6(2) = ‘30’. " 30 days per monthelseif i_date+4(2) = ‘02’. " 闰年的问题
 e_date+6(2) = ‘28’.
 check_year_1 = i_date(4) mod 4. " all 4 years is leap year
 if check_year_1 = 0.
 e_date+6(2) = ‘29’.
 check_year_1 = i_date(4) mod 100." but not all 100 years
 check_year_2 = i_date(4) mod 400." excluding all 400 years
 if check_year_1 = 0
 and check_year_2 <> 0.
 e_date+6(2) = ‘28’.
 endif.
 endif.
 endif.endfunction.