>>SOURCE FORMAT IS FREE
*> cobol-copybook-audit.cob - ACCT-AUDIT, the third of
*>          three programs sharing one record layout: read last month's
*>          and this month's masters side by side and prove the posting
*>          run balanced (same accounts in the same order, no status
*>          changed, no balance fell, no closed account credited, and
*>          old total + movement = new total)
*> Dialect: GnuCOBOL 3.x, free format
*> Status : desk-checked against the GnuCOBOL Programmer's Guide (3.2
*>          COPY, 3.3 REPLACE) and the IBM Enterprise COBOL 6.4 Language
*>          Reference (pp. 700-703); compiled and run with GnuCOBOL 3.2
*>          on 2026-10-29
*> Inputs : datasets/cobol-copybook-copy-replacing.dat (last month)
*>          acct-master-new.dat (this month, written by ACCT-POST)
*>          code/cobol-copybook-copy-replacing.cpy (the layout, renamed
*>          here by REPLACE statements rather than a phrase on the COPY)
*> Outputs: DISPLAY lines only
*> Build  : cobc -x -I code -o acct-audit code/cobol-copybook-audit.cob
*> Run    : ./acct-audit   (after ./acct-post, from the same folder)
IDENTIFICATION DIVISION.
PROGRAM-ID. ACCT-AUDIT.
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
    SELECT Old-Master
        ASSIGN TO "datasets/cobol-copybook-copy-replacing.dat"
        ORGANIZATION IS LINE SEQUENTIAL
        FILE STATUS IS WS-Old-FS.
    SELECT New-Master
        ASSIGN TO "acct-master-new.dat"
        ORGANIZATION IS LINE SEQUENTIAL
        FILE STATUS IS WS-New-FS.
DATA DIVISION.
FILE SECTION.
*> The same renaming ACCT-POST does, written as REPLACE statements.
*> Each one stays in force until the next; REPLACE OFF ends the last.
REPLACE LEADING ==Acct-== BY ==Old-==.
FD  Old-Master.
    COPY "cobol-copybook-copy-replacing.cpy".
REPLACE LEADING ==Acct-== BY ==New-==.
FD  New-Master.
    COPY "cobol-copybook-copy-replacing.cpy".
REPLACE OFF.
WORKING-STORAGE SECTION.
77 WS-Old-FS             PIC XX.
77 WS-New-FS             PIC XX.
01 WS-Flags.
   05 WS-Old-EOF         PIC X VALUE "N".
      88 Old-Done              VALUE "Y".
   05 WS-New-EOF         PIC X VALUE "N".
      88 New-Done              VALUE "Y".
77 WS-Pairs              PIC 9(5)     VALUE 0.
77 WS-Raised             PIC 9(5)     VALUE 0.
77 WS-Unchanged          PIC 9(5)     VALUE 0.
77 WS-Problems           PIC 9(5)     VALUE 0.
77 WS-Old-Total          PIC 9(9)V99  VALUE 0.
77 WS-New-Total          PIC 9(9)V99  VALUE 0.
77 WS-Movement           PIC 9(9)V99  VALUE 0.
77 WS-Check-Total        PIC 9(9)V99  VALUE 0.
77 WS-Show-Count         PIC ZZ,ZZ9.
77 WS-Show-Money         PIC Z,ZZZ,ZZ9.99.
PROCEDURE DIVISION.
Main-Paragraph.
    OPEN INPUT Old-Master
    IF WS-Old-FS NOT = "00"
       DISPLAY "Cannot open the old master, status " WS-Old-FS
       STOP RUN
    END-IF
    OPEN INPUT New-Master
    IF WS-New-FS NOT = "00"
       DISPLAY "Cannot open acct-master-new.dat, status " WS-New-FS
       CLOSE Old-Master
       STOP RUN
    END-IF
    PERFORM Read-Old
    PERFORM Read-New
    PERFORM UNTIL Old-Done OR New-Done
       PERFORM Compare-Pair
       PERFORM Read-Old
       PERFORM Read-New
    END-PERFORM
    IF NOT (Old-Done AND New-Done)
       ADD 1 TO WS-Problems
       DISPLAY "Record counts differ between the two masters"
    END-IF
    CLOSE Old-Master New-Master
    ADD WS-Old-Total WS-Movement GIVING WS-Check-Total
    MOVE WS-Pairs TO WS-Show-Count
    DISPLAY "ACCT-AUDIT pairs compared   " WS-Show-Count
    MOVE WS-Raised TO WS-Show-Count
    DISPLAY "ACCT-AUDIT balances raised  " WS-Show-Count
    MOVE WS-Unchanged TO WS-Show-Count
    DISPLAY "ACCT-AUDIT balances same    " WS-Show-Count
    MOVE WS-Old-Total TO WS-Show-Money
    DISPLAY "ACCT-AUDIT old total        " WS-Show-Money
    MOVE WS-Movement TO WS-Show-Money
    DISPLAY "ACCT-AUDIT movement         " WS-Show-Money
    MOVE WS-New-Total TO WS-Show-Money
    DISPLAY "ACCT-AUDIT new total        " WS-Show-Money
    IF WS-Problems = 0 AND WS-Check-Total = WS-New-Total
       DISPLAY "ACCT-AUDIT result           balanced"
    ELSE
       MOVE WS-Problems TO WS-Show-Count
       DISPLAY "ACCT-AUDIT result           NOT balanced, problems "
               WS-Show-Count
    END-IF
    STOP RUN.

Read-Old.
    READ Old-Master
       AT END
          SET Old-Done TO TRUE
    END-READ
    IF WS-Old-FS NOT = "00" AND WS-Old-FS NOT = "10"
       DISPLAY "Old master read failed, status " WS-Old-FS
       STOP RUN
    END-IF.

Read-New.
    READ New-Master
       AT END
          SET New-Done TO TRUE
    END-READ
    IF WS-New-FS NOT = "00" AND WS-New-FS NOT = "10"
       DISPLAY "New master read failed, status " WS-New-FS
       STOP RUN
    END-IF.

*> Every Old- and New- name below exists only because of the REPLACE
*> statements in the FILE SECTION.
Compare-Pair.
    ADD 1 TO WS-Pairs
    ADD Old-Balance TO WS-Old-Total
    ADD New-Balance TO WS-New-Total
    IF New-Id NOT = Old-Id
       ADD 1 TO WS-Problems
       DISPLAY "Out of step: old " Old-Id " new " New-Id
    END-IF
    IF New-Status NOT = Old-Status
       ADD 1 TO WS-Problems
       DISPLAY "Status changed on account " Old-Id
    END-IF
    IF New-Balance > Old-Balance
       ADD 1 TO WS-Raised
       COMPUTE WS-Movement = WS-Movement + New-Balance - Old-Balance
       IF New-Closed
          ADD 1 TO WS-Problems
          DISPLAY "Closed account credited: " Old-Id
       END-IF
    ELSE
       IF New-Balance = Old-Balance
          ADD 1 TO WS-Unchanged
       ELSE
          ADD 1 TO WS-Problems
          DISPLAY "Balance fell on account " Old-Id
       END-IF
    END-IF.