>>SOURCE FORMAT IS FREE
*> cobol-occurs-subscripts-table.cob — monthly totals in an OCCURS table
*> Dialect: GnuCOBOL 3.x, free format
*> Status : desk-checked against the GnuCOBOL 3.2 Programmer's Guide;
*>          NOT compiled (no cobc on the authoring machine)
*> Inputs : none (the twelve monthly figures are VALUE clauses)
*> Outputs: DISPLAY lines on the console
*> Build  : cobc -x cobol-occurs-subscripts-table.cob
*> Run    : ./cobol-occurs-subscripts-table
*>          (Windows: cobol-occurs-subscripts-table.exe)
IDENTIFICATION DIVISION.
PROGRAM-ID. MONTHLY-TOTALS.
ENVIRONMENT DIVISION.
DATA DIVISION.
WORKING-STORAGE SECTION.
*> Twelve figures given compile-time values, then viewed as a table
*> through REDEFINES (the technique the Programmer's Guide documents
*> under VALUE).
01 Month-Values.
   05 FILLER              PIC 9(7)V99 VALUE 125430.50.
   05 FILLER              PIC 9(7)V99 VALUE  98210.00.
   05 FILLER              PIC 9(7)V99 VALUE 143875.25.
   05 FILLER              PIC 9(7)V99 VALUE 110004.10.
   05 FILLER              PIC 9(7)V99 VALUE 156320.00.
   05 FILLER              PIC 9(7)V99 VALUE 171009.99.
   05 FILLER              PIC 9(7)V99 VALUE 132500.00.
   05 FILLER              PIC 9(7)V99 VALUE  99875.40.
   05 FILLER              PIC 9(7)V99 VALUE 148200.75.
   05 FILLER              PIC 9(7)V99 VALUE 160010.00.
   05 FILLER              PIC 9(7)V99 VALUE 189430.20.
   05 FILLER              PIC 9(7)V99 VALUE 210655.55.
01 Month-Table REDEFINES Month-Values.
   05 Month-Total         OCCURS 12 TIMES PIC 9(7)V99.
01 Month-Names-Values     PIC X(36)
                          VALUE "JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC".
01 Month-Names REDEFINES Month-Names-Values.
   05 Month-Name          OCCURS 12 TIMES PIC X(3).
*> A table filled at run time.
01 Quarter-Table.
   05 Quarter-Total       OCCURS 4 TIMES PIC 9(8)V99.
*> A two-dimensional table: OCCURS inside OCCURS.
01 Grid.
   05 Grid-Row            OCCURS 3 TIMES.
      10 Grid-Cell        OCCURS 4 TIMES PIC 9(3).
*> A variable-length table: room for 12, but only Active-Months count.
77 Active-Months          PIC 99 VALUE 9.
01 YTD-Table.
   05 YTD-Total           OCCURS 1 TO 12 TIMES
                          DEPENDING ON Active-Months
                          PIC 9(7)V99.
77 M                      PIC 99.
77 Q                      PIC 9.
77 R                      PIC 9.
77 C                      PIC 9.
77 Max-Month              PIC 99 VALUE 1.
77 Grand-Total            PIC 9(9)V99 VALUE 0.
77 Show-Amt               PIC Z(6)9.99.
77 Show-Total             PIC Z(8)9.99.
PROCEDURE DIVISION.
Main-Paragraph.
*> Walk the table once: print, sum, and remember the largest entry.
    PERFORM VARYING M FROM 1 BY 1 UNTIL M > 12
       MOVE Month-Total(M) TO Show-Amt
       DISPLAY Month-Name(M) " " Show-Amt
       ADD Month-Total(M) TO Grand-Total
       IF Month-Total(M) > Month-Total(Max-Month)
          MOVE M TO Max-Month
       END-IF
    END-PERFORM
    MOVE Grand-Total TO Show-Total
    DISPLAY "Year total   " Show-Total
    DISPLAY "Best month   " Month-Name(Max-Month)
*> A subscript is a literal, an identifier, or an arithmetic expression.
    DISPLAY "First month  " Month-Name(1)
    MOVE 6 TO M
    DISPLAY "Month M + 1  " Month-Name(M + 1)
    PERFORM VARYING Q FROM 1 BY 1 UNTIL Q > 4
       COMPUTE Quarter-Total(Q) = Month-Total(3 * Q - 2)
                                + Month-Total(3 * Q - 1)
                                + Month-Total(3 * Q)
       MOVE Quarter-Total(Q) TO Show-Total
       DISPLAY "Quarter " Q "    " Show-Total
    END-PERFORM
*> Two subscripts for two dimensions; AFTER drives the inner loop.
    PERFORM VARYING R FROM 1 BY 1 UNTIL R > 3
            AFTER C FROM 1 BY 1 UNTIL C > 4
       COMPUTE Grid-Cell(R, C) = R * 10 + C
    END-PERFORM
    PERFORM VARYING R FROM 1 BY 1 UNTIL R > 3
       DISPLAY "Row " R ": " Grid-Cell(R, 1) " " Grid-Cell(R, 2)
               " " Grid-Cell(R, 3) " " Grid-Cell(R, 4)
    END-PERFORM
*> OCCURS DEPENDING ON: the storage is always the maximum, but the
*> table logically has Active-Months entries.
    MOVE 0 TO Grand-Total
    PERFORM VARYING M FROM 1 BY 1 UNTIL M > Active-Months
       MOVE Month-Total(M) TO YTD-Total(M)
       ADD YTD-Total(M) TO Grand-Total
    END-PERFORM
    MOVE Grand-Total TO Show-Total
    DISPLAY "YTD through " Month-Name(Active-Months) " " Show-Total
    STOP RUN.