| Figure 1: An old RPG/400 customer maintenance program | |
| 
  FCUSTFILEUF  E           K        DISK                      A
     FCUSTS   CF  E                    WORKSTN
     E                    ERR     1   8 60
     C                     EXSR SCRN1
     C                     EXSR SCRN2
     C        N12          EXSR UPDATE
     C        N12          EXSR CLEAR
      *****************************************************
      * ASK FOR CUSTOMER NUMBER
      *****************************************************
     C           SCRN1     BEGSR
     C           SCMSG     DOUEQ*BLANKS
      *
 | |
|       
     C                     EXFMTCUSTS1
		 | A | 
| 
     C                     MOVE *BLANKS   SCMSG
		 | B | 
|      
      *
 | |
|       
     C           *IN03     IFEQ *ON
     C                     MOVE *ON       *INLR
     C                     RETRN
     C                     ENDIF
		 | C | 
|      
      *
 | |
|       
     C           SCCUST    CHAINCUSTFILE            N99
     C           *IN99     IFEQ *ON
     C           *IN10     ANDEQ*OFF
     C                     MOVELERR,1     SCMSG
     C                     ENDIF
      *
     C           *IN99     IFEQ *OFF
     C           *IN10     ANDEQ*ON
     C                     MOVELERR,2     SCMSG
     C                     ENDIF
		 | D | 
|      
      *
     C                     ENDDO
     C                     ENDSR
 |