How to Lock and Unlock Users in abap sap

REPORT ZUSR_LOCK.
TABLES USR02.
DATA: Z_USR02 LIKE USR02 OCCURS 0 WITH HEADER LINE.
DATA: ZCOUNT TYPE I,
      DEST(72).

*-- Select-Options
-----------------------------------------------------
SELECTION-SCREEN BEGIN OF BLOCK 1 WITH FRAME TITLE TEXT-100.
SELECT-OPTIONS: S_BNAME FOR USR02-BNAME NO INTERVALS.
*                S_CLASS FOR USR02-CLASS NO INTERVALS.
PARAMETER: ZTEST AS CHECKBOX DEFAULT 'X'.
selection-screen end of block 1.

SELECTION-SCREEN BEGIN OF BLOCK 2 WITH FRAME TITLE TEXT-110.
PARAMETERS: ZUFLAG_L RADIOBUTTON GROUP RADI,
           ZUFLAG_U RADIOBUTTON GROUP RADI.
SELECTION-SCREEN END OF BLOCK 2.
*-- Select-Options
-----------------------------------------------------
AT SELECTION-SCREEN.
 IF SY-SUBRC NE 0.
   MESSAGE I001(CJ) WITH TEXT-001.
   EXIT.
 ENDIF.
 IF S_BNAME IS INITIAL.
* and    S_CLASS IS INITIAL.
   MESSAGE E001(CJ) WITH TEXT-003.
 ENDIF.

START-OF-SELECTION.

IF ZUFLAG_L EQ 'X'.
 SELECT * FROM USR02 INTO TABLE Z_USR02 WHERE BNAME IN S_BNAME
*                                           AND CLASS IN S_CLASS
                                          AND UFLAG EQ ' '.
ENDIF.

IF ZUFLAG_U EQ 'X'.
 SELECT * FROM USR02 INTO TABLE Z_USR02 WHERE BNAME IN S_BNAME
*                                           AND CLASS IN S_CLASS
                                          AND UFLAG EQ '64'.
 ENDIF.
 IF SY-SUBRC <> 0.
   MESSAGE I001(CJ) WITH TEXT-002.
   EXIT.
 ELSE.
   IF ZTEST EQ ' '.
     LOOP AT Z_USR02.
       SELECT SINGLE * FROM USR02 WHERE BNAME EQ Z_USR02-BNAME.
       IF ZUFLAG_L EQ 'X'.
         USR02-UFLAG = '64'.
       ENDIF.
       IF ZUFLAG_U EQ 'X'.
         USR02-UFLAG = '0'.
       ENDIF.
       MODIFY USR02.
       IF SY-SUBRC EQ 0.
         ZCOUNT = ZCOUNT + 1.
*          z_usr02-zbvmaster = 'X'.
         MODIFY Z_USR02.
       ENDIF.
     ENDLOOP.
   ENDIF.
 ENDIF.
END-OF-SELECTION.

*Write result
 IF NOT ZCOUNT IS INITIAL.
   IF ZUFLAG_L EQ 'X'.
     WRITE TEXT-200 TO DEST(40).
     WRITE ZCOUNT TO DEST+41(3).
   ENDIF.
   IF ZUFLAG_U EQ 'X'.
     WRITE: TEXT-300 TO DEST(40).
     WRITE ZCOUNT TO DEST+41(3).
   ENDIF.
 ELSE.
   WRITE: TEXT-400.
 ENDIF.

 LOOP AT Z_USR02.
   WRITE: /3 Z_USR02-BNAME.
 ENDLOOP.

TOP-OF-PAGE.
 WRITE: /1 DEST COLOR 3.