Macro to validate Date in abap sap

*======================================================================*
* Programme   : zdate_validate                                         *
* Title       : Macro to validate Date                                 *
* Author      : Abhishek Kumar                                         *
* Description : This program has two macros and a sample code which is *
*               showing how to use that.                               *
*               Macro 1. > Val_date                                    *
*               Macro 2. > Valdate                                     *
*               It return SY-Subrc value if it 0 then the entered date *
*               is valid else either the date is invalid or the        *
*               specified format is invalid                            *
*----------------------------------------------------------------------*
* Created and Designed by Abhishek Kumar in Nov 2001.                  *
*----------------------------------------------------------------------*
*Abhishek is not responsible for any damages caused by the use or      *
*misuse of this program and cannot provide any warranty with this      *
*program. Use it entirely at your own risk.                            *
*                                                                      *
*You are not authorised to make any changes without prior written      *
*permission from the author.                                           *
*======================================================================*

PROGRAM ZDATE_VALIDATE .
* Validation of Date
DEFINE VAL_DATE.
 CLEAR: %_DATE1,
        %_DATE2.
 %_DATE1(4)   = &1. "Year
 %_DATE1+4(2) = &2. "Month
 %_DATE1+6(2) = &3. "Date
 %_DATE2 = %_DATE1 - 1.
 %_DATE2 = %_DATE2 + 1.
 IF %_DATE1 <> %_DATE2.
   SY-SUBRC = 1.
 ELSE.
   SY-SUBRC = 0.
 ENDIF.
END-OF-DEFINITION.

DEFINE VALDATE.
***************************************************
* Passing Parameters: &1 - Date
*                     &2 - Date Format
*
* Date Format:
* DDMMYYYY  MMDDYYYY  YYYYMMDD  YYYYDDMM
*
* SY-SUBRC Return Value:
*                     1 invalid date
*                     0 Valid Date
*                     2 Invalid Format
***************************************************
 DATA: %_DATE1 LIKE SY-DATUM  ,
       %_DATE2 LIKE SY-DATUM ,
       %_DATE3(8).
 case &2.
   when 'DDMMYYYY'.
     val_date &1+4(4) &1+2(2) &1+0(2).
   when 'MMDDYYYY'.
     val_date &1+4(4) &1+0(2) &1+2(2).
   when 'YYYYMMDD'.
     val_date &1+0(4) &1+4(2) &1+6(2).
   when 'MMYYYYDD'.
     val_date &1+2(4) &1+0(2) &1+6(2).
   when others.
     sy-subrc =  2.
 endcase.
END-OF-DEFINITION.

***********************************************
*      SAMPLE USE of above MACRO              *
***********************************************

DATA: V_DATE(8).
V_DATE = '30022002'.
*=>
VALDATE V_DATE 'DDMMYYYY'.
*=>
IF SY-SUBRC = 0.
 WRITE:/ 'Valid Date'.
ELSEIF SY-SUBRC = 1.
 WRITE:/ 'Invalid Date'.
ELSEIF SY-SUBRC = 2.
 WRITE:/ 'Invalid Format'.
ENDIF.
*********************************************************************