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COBOL Tutorial

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COBOL Report Generation

Report generation in COBOL is the process of creating formatted, professional output documents from data. Reports are essential for business applications, providing readable summaries, transaction listings, financial statements, and analytical data. Effective report generation involves organizing data logically, applying proper formatting, calculating totals and subtotals, handling page breaks, and creating clear, professional layouts. Mastering report generation is crucial for creating business-ready output in mainframe COBOL applications.

What is Report Generation?

Report generation transforms raw data into formatted, readable documents. A well-designed report includes:

  • Headers: Report title, date, page numbers, column headings
  • Detail lines: Individual data records formatted for readability
  • Control breaks: Grouping data and showing subtotals
  • Totals and subtotals: Aggregated data at group and report levels
  • Footers: Summary information, totals, page information
  • Formatting: Proper alignment, spacing, and number formatting

Reports serve various purposes: financial statements, inventory listings, transaction summaries, customer statements, management reports, and analytical summaries. Effective report generation makes data accessible and actionable.

Basic Report Structure

A typical COBOL report follows this structure:

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. SALES-REPORT.
       
       ENVIRONMENT DIVISION.
       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
           SELECT INPUT-FILE ASSIGN TO 'SALES.DAT'
               ORGANIZATION IS SEQUENTIAL
               ACCESS MODE IS SEQUENTIAL.
           SELECT REPORT-FILE ASSIGN TO 'SALES.RPT'
               ORGANIZATION IS SEQUENTIAL
               ACCESS MODE IS SEQUENTIAL.
       
       DATA DIVISION.
       FILE SECTION.
       FD  INPUT-FILE
           LABEL RECORDS ARE STANDARD.
       01  INPUT-RECORD.
           05  SALES-DATE          PIC 9(8).
           05  SALES-REGION         PIC X(10).
           05  SALES-AMOUNT         PIC 9(7)V99.
           05  SALES-REP           PIC X(20).
       
       FD  REPORT-FILE
           LABEL RECORDS ARE STANDARD.
       01  REPORT-LINE             PIC X(132).
       
       WORKING-STORAGE SECTION.
       01  WS-CONTROL-FIELDS.
           05  WS-PAGE-NUMBER       PIC 9(4) VALUE 0.
           05  WS-LINE-COUNT        PIC 9(2) VALUE 0.
           05  WS-LINES-PER-PAGE    PIC 9(2) VALUE 55.
           05  WS-PREV-REGION       PIC X(10) VALUE SPACES.
       
       01  WS-TOTALS.
           05  WS-REGION-TOTAL      PIC 9(9)V99 VALUE 0.
           05  WS-GRAND-TOTAL       PIC 9(9)V99 VALUE 0.
       
       01  WS-HEADER-LINE.
           05  FILLER               PIC X(20) VALUE SPACES.
           05  FILLER               PIC X(30) VALUE 
               'SALES REPORT BY REGION'.
           05  FILLER               PIC X(50) VALUE SPACES.
           05  FILLER               PIC X(6) VALUE 'PAGE: '.
           05  WS-PAGE-NUM-OUT      PIC ZZZ9.
       
       01  WS-COLUMN-HEADER.
           05  FILLER               PIC X(5) VALUE SPACES.
           05  FILLER               PIC X(10) VALUE 'DATE'.
           05  FILLER               PIC X(15) VALUE SPACES.
           05  FILLER               PIC X(10) VALUE 'REGION'.
           05  FILLER               PIC X(15) VALUE SPACES.
           05  FILLER               PIC X(12) VALUE 'AMOUNT'.
           05  FILLER               PIC X(15) VALUE SPACES.
           05  FILLER               PIC X(20) VALUE 'SALES REP'.
       
       01  WS-DETAIL-LINE.
           05  FILLER               PIC X(5) VALUE SPACES.
           05  WS-DATE-OUT          PIC 99/99/9999.
           05  FILLER               PIC X(10) VALUE SPACES.
           05  WS-REGION-OUT        PIC X(10).
           05  FILLER               PIC X(10) VALUE SPACES.
           05  WS-AMOUNT-OUT        PIC $,$$$,$$$.99.
           05  FILLER               PIC X(10) VALUE SPACES.
           05  WS-REP-OUT           PIC X(20).
       
       01  WS-SUBTOTAL-LINE.
           05  FILLER               PIC X(5) VALUE SPACES.
           05  FILLER               PIC X(25) VALUE 
               'REGION SUBTOTAL: '.
           05  WS-REGION-OUT-SUB     PIC X(10).
           05  FILLER               PIC X(20) VALUE SPACES.
           05  WS-SUBTOTAL-OUT       PIC $,$$$,$$$,$$$.99.
       
       01  WS-GRAND-TOTAL-LINE.
           05  FILLER               PIC X(5) VALUE SPACES.
           05  FILLER               PIC X(25) VALUE 
               'GRAND TOTAL: '.
           05  FILLER               PIC X(45) VALUE SPACES.
           05  WS-GRAND-TOTAL-OUT    PIC $,$$$,$$$,$$$.99.

This structure defines the input file, output report file, control fields for page management, totals for accumulation, and formatted output lines for headers, detail, subtotals, and grand totals.

Report Headers

Headers appear at the top of each page and provide context about the report. A good header includes:

  • Report title: Clear identification of the report purpose
  • Date: Report generation date or data date
  • Page number: Current page for multi-page reports
  • Column headings: Labels for each data column

Header Printing Logic

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       PROCEDURE DIVISION.
       MAIN-PARA.
           OPEN INPUT INPUT-FILE
                OUTPUT REPORT-FILE
           
           PERFORM PRINT-REPORT-HEADER
           PERFORM PROCESS-INPUT-FILE
           PERFORM PRINT-GRAND-TOTAL
           
           CLOSE INPUT-FILE
                 REPORT-FILE
           
           STOP RUN.
       
       PRINT-REPORT-HEADER.
           ADD 1 TO WS-PAGE-NUMBER
           MOVE WS-PAGE-NUMBER TO WS-PAGE-NUM-OUT
           MOVE WS-HEADER-LINE TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING PAGE
           
           MOVE SPACES TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE
           
           MOVE WS-COLUMN-HEADER TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE
           
           MOVE ALL '-' TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE
           
           MOVE 4 TO WS-LINE-COUNT.

This header paragraph:

  • Increments page number: Tracks which page we're on
  • Prints title and page number: Provides report identification
  • Adds blank line: Creates visual separation
  • Prints column headings: Labels each column
  • Prints separator line: Visual divider using dashes
  • Sets line count: Tracks lines printed on current page

Detail Lines

Detail lines display individual data records. Each input record typically produces one detail line, formatted for readability.

Detail Line Printing

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       PROCESS-INPUT-FILE.
           PERFORM UNTIL END-OF-FILE
               READ INPUT-FILE
                   AT END
                       SET END-OF-FILE TO TRUE
                   NOT AT END
                       PERFORM CHECK-CONTROL-BREAK
                       PERFORM PRINT-DETAIL-LINE
                       PERFORM ACCUMULATE-TOTALS
               END-READ
           END-PERFORM.
       
       PRINT-DETAIL-LINE.
           PERFORM CHECK-PAGE-BREAK
           
           MOVE SALES-DATE TO WS-DATE-OUT
           MOVE SALES-REGION TO WS-REGION-OUT
           MOVE SALES-AMOUNT TO WS-AMOUNT-OUT
           MOVE SALES-REP TO WS-REP-OUT
           
           MOVE WS-DETAIL-LINE TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE
           
           ADD 1 TO WS-LINE-COUNT.

The detail line printing process:

  • Checks page break: Ensures we don't exceed page limits
  • Moves data to output fields: Transfers input data to formatted output fields
  • Formats numbers: Uses editing characters for proper display
  • Writes the line: Outputs the formatted detail line
  • Updates line count: Tracks lines printed for page break logic

Control Breaks

Control breaks occur when a control field (grouping field) changes value. They signal the start of a new group and trigger printing of subtotals for the previous group.

Control Break Logic

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       CHECK-CONTROL-BREAK.
           IF WS-PREV-REGION NOT = SPACES
               IF SALES-REGION NOT = WS-PREV-REGION
                   PERFORM PRINT-REGION-SUBTOTAL
                   PERFORM INITIALIZE-REGION-TOTAL
               END-IF
           END-IF
           
           MOVE SALES-REGION TO WS-PREV-REGION.
       
       PRINT-REGION-SUBTOTAL.
           PERFORM CHECK-PAGE-BREAK
           
           MOVE SPACES TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE
           ADD 1 TO WS-LINE-COUNT
           
           MOVE WS-PREV-REGION TO WS-REGION-OUT-SUB
           MOVE WS-REGION-TOTAL TO WS-SUBTOTAL-OUT
           MOVE WS-SUBTOTAL-LINE TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE
           ADD 1 TO WS-LINE-COUNT
           
           MOVE ALL '-' TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE
           ADD 1 TO WS-LINE-COUNT.
       
       INITIALIZE-REGION-TOTAL.
           MOVE 0 TO WS-REGION-TOTAL.

Control break processing:

  • Compares current to previous: Detects when control field changes
  • Prints subtotal: Shows totals for the completed group
  • Resets accumulator: Prepares for the new group
  • Updates previous value: Tracks the current group for next comparison

Multiple Level Control Breaks

Reports can have multiple control break levels (major, intermediate, minor):

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       WORKING-STORAGE SECTION.
       01  WS-CONTROL-FIELDS.
           05  WS-PREV-DEPARTMENT    PIC X(10) VALUE SPACES.
           05  WS-PREV-DIVISION      PIC X(10) VALUE SPACES.
           05  WS-PREV-REGION        PIC X(10) VALUE SPACES.
       
       01  WS-TOTALS.
           05  WS-DEPARTMENT-TOTAL   PIC 9(9)V99 VALUE 0.
           05  WS-DIVISION-TOTAL     PIC 9(9)V99 VALUE 0.
           05  WS-REGION-TOTAL       PIC 9(9)V99 VALUE 0.
           05  WS-GRAND-TOTAL        PIC 9(9)V99 VALUE 0.
       
       PROCEDURE DIVISION.
       CHECK-CONTROL-BREAKS.
           *> Check major break (Region)
           IF WS-PREV-REGION NOT = SPACES
               IF SALES-REGION NOT = WS-PREV-REGION
                   PERFORM PRINT-DIVISION-SUBTOTAL
                   PERFORM PRINT-REGION-SUBTOTAL
                   PERFORM INITIALIZE-REGION-TOTALS
               ELSE
                   *> Check intermediate break (Division)
                   IF SALES-DIVISION NOT = WS-PREV-DIVISION
                       PERFORM PRINT-DIVISION-SUBTOTAL
                       PERFORM INITIALIZE-DIVISION-TOTALS
                   ELSE
                       *> Check minor break (Department)
                       IF SALES-DEPARTMENT NOT = WS-PREV-DEPARTMENT
                           PERFORM PRINT-DEPARTMENT-SUBTOTAL
                           PERFORM INITIALIZE-DEPARTMENT-TOTALS
                       END-IF
                   END-IF
               END-IF
           END-IF
           
           MOVE SALES-REGION TO WS-PREV-REGION
           MOVE SALES-DIVISION TO WS-PREV-DIVISION
           MOVE SALES-DEPARTMENT TO WS-PREV-DEPARTMENT.

Multiple level breaks allow hierarchical grouping: regions contain divisions, divisions contain departments. Subtotals are printed at each level when that level's control field changes.

Page Break Handling

Page breaks ensure reports don't exceed page limits and maintain professional formatting. You track the line count and trigger a new page when the limit is reached.

Page Break Logic

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       CHECK-PAGE-BREAK.
           IF WS-LINE-COUNT >= WS-LINES-PER-PAGE
               PERFORM PRINT-PAGE-FOOTER
               PERFORM PRINT-REPORT-HEADER
           END-IF.
       
       PRINT-PAGE-FOOTER.
           *> Print footer information if needed
           MOVE SPACES TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE
           
           MOVE ALL '-' TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE
           
           MOVE SPACES TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE.

Page break handling:

  • Line count check: Compare current line count to maximum lines per page
  • Print footer: Optional footer information before page break
  • Advance page: Use AFTER ADVANCING PAGE to start new page
  • Print header: Print header on new page
  • Reset line count: Start counting lines on new page

Totals and Subtotals

Totals provide summary information at various levels. Subtotals appear at control breaks, grand totals at the end of the report.

Accumulating Totals

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       ACCUMULATE-TOTALS.
           ADD SALES-AMOUNT TO WS-REGION-TOTAL
           ADD SALES-AMOUNT TO WS-GRAND-TOTAL.
       
       PRINT-REGION-SUBTOTAL.
           PERFORM CHECK-PAGE-BREAK
           
           MOVE SPACES TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE
           ADD 1 TO WS-LINE-COUNT
           
           MOVE WS-PREV-REGION TO WS-REGION-OUT-SUB
           MOVE WS-REGION-TOTAL TO WS-SUBTOTAL-OUT
           MOVE WS-SUBTOTAL-LINE TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE
           ADD 1 TO WS-LINE-COUNT.
       
       PRINT-GRAND-TOTAL.
           PERFORM CHECK-PAGE-BREAK
           
           MOVE SPACES TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE
           ADD 1 TO WS-LINE-COUNT
           
           MOVE ALL '=' TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE
           ADD 1 TO WS-LINE-COUNT
           
           MOVE WS-GRAND-TOTAL TO WS-GRAND-TOTAL-OUT
           MOVE WS-GRAND-TOTAL-LINE TO REPORT-LINE
           WRITE REPORT-LINE
           AFTER ADVANCING 1 LINE
           ADD 1 TO WS-LINE-COUNT.

Total accumulation and printing:

  • Accumulate during processing: Add each record's value to totals
  • Print subtotals at breaks: Display group totals when control breaks occur
  • Print grand total at end: Display final totals after all records processed
  • Format totals: Use editing characters for proper display

Number Formatting

Proper number formatting makes reports readable and professional. COBOL provides editing characters for formatting.

Editing Characters

COBOL Editing Characters for Number Formatting
CharacterPurposeExample
$Dollar sign (floating or fixed position)PIC $,$$$,$$$.99 → $1,234.56
,Comma separator for thousandsPIC 9,999,999 → 1,234,567
.Decimal pointPIC 999.99 → 123.45
ZZero suppression (leading zeros become spaces)PIC ZZZ9 → " 123" (not "0123")
-Negative sign (floating)PIC ---,---.99 → -1,234.56
+Plus or minus signPIC +999.99 → +123.45
CRCredit indicator (appears if negative)PIC 999.99CR → 123.45CR if negative
DBDebit indicator (appears if negative)PIC 999.99DB → 123.45DB if negative

Formatting Examples

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       WORKING-STORAGE SECTION.
       01  WS-RAW-AMOUNT            PIC 9(7)V99 VALUE 1234567.89.
       01  WS-FORMATTED-AMOUNTS.
           05  WS-CURRENCY-FMT       PIC $,$$$,$$$.99.
           05  WS-NO-DECIMAL        PIC Z,ZZZ,ZZ9.
           05  WS-PERCENT-FMT        PIC ZZ9.99.
           05  WS-SIGNED-FMT         PIC ---,---.99.
       
       PROCEDURE DIVISION.
       FORMAT-EXAMPLES.
           *> Currency format
           MOVE WS-RAW-AMOUNT TO WS-CURRENCY-FMT
           *> Result: $1,234,567.89
           
           *> No decimal, zero suppression
           MOVE WS-RAW-AMOUNT TO WS-NO-DECIMAL
           *> Result: 1,234,568 (rounded, no leading zeros)
           
           *> Percentage format
           MOVE 123.45 TO WS-PERCENT-FMT
           *> Result: "123.45" (leading zeros suppressed)
           
           *> Signed format
           MOVE -1234.56 TO WS-SIGNED-FMT
           *> Result: "-1,234.56"

Editing characters transform raw numbers into readable, professional formats suitable for business reports.

Complete Report Example

Here's a complete report generation program combining all concepts:

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       IDENTIFICATION DIVISION.
       PROGRAM-ID. COMPLETE-REPORT.
       
       ENVIRONMENT DIVISION.
       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
           SELECT SALES-FILE ASSIGN TO 'SALES.DAT'.
           SELECT REPORT-FILE ASSIGN TO 'REPORT.OUT'.
       
       DATA DIVISION.
       FILE SECTION.
       FD  SALES-FILE.
       01  SALES-RECORD.
           05  SALE-DATE             PIC 9(8).
           05  SALE-REGION            PIC X(10).
           05  SALE-AMOUNT            PIC 9(7)V99.
           05  SALE-REP               PIC X(20).
       
       FD  REPORT-FILE.
       01  REPORT-LINE               PIC X(132).
       
       WORKING-STORAGE SECTION.
       01  WS-CONTROL.
           05  WS-PAGE-NUM           PIC 9(4) VALUE 0.
           05  WS-LINE-CTR           PIC 9(2) VALUE 0.
           05  WS-MAX-LINES           PIC 9(2) VALUE 55.
           05  WS-PREV-REGION         PIC X(10) VALUE SPACES.
           05  WS-EOF-FLAG            PIC X VALUE 'N'.
               88  END-OF-FILE        VALUE 'Y'.
       
       01  WS-TOTALS.
           05  WS-REGION-TOT         PIC 9(9)V99 VALUE 0.
           05  WS-GRAND-TOT          PIC 9(9)V99 VALUE 0.
       
       01  WS-HEADER.
           05  FILLER                PIC X(40) VALUE SPACES.
           05  FILLER                PIC X(20) VALUE 'SALES REPORT'.
           05  FILLER                PIC X(40) VALUE SPACES.
           05  FILLER                PIC X(6) VALUE 'PAGE: '.
           05  WS-PAGE-OUT           PIC ZZZ9.
       
       01  WS-COL-HEADER.
           05  FILLER                PIC X(5) VALUE SPACES.
           05  FILLER                PIC X(10) VALUE 'DATE'.
           05  FILLER                PIC X(10) VALUE SPACES.
           05  FILLER                PIC X(10) VALUE 'REGION'.
           05  FILLER                PIC X(10) VALUE SPACES.
           05  FILLER                PIC X(12) VALUE 'AMOUNT'.
           05  FILLER                PIC X(10) VALUE SPACES.
           05  FILLER                PIC X(20) VALUE 'SALES REP'.
       
       01  WS-DETAIL.
           05  FILLER                PIC X(5) VALUE SPACES.
           05  WS-DATE-OUT           PIC 99/99/9999.
           05  FILLER                PIC X(10) VALUE SPACES.
           05  WS-REG-OUT            PIC X(10).
           05  FILLER                PIC X(10) VALUE SPACES.
           05  WS-AMT-OUT            PIC $,$$$,$$$.99.
           05  FILLER                PIC X(10) VALUE SPACES.
           05  WS-REP-OUT            PIC X(20).
       
       01  WS-SUBTOTAL.
           05  FILLER                PIC X(5) VALUE SPACES.
           05  FILLER                PIC X(20) VALUE 'REGION TOTAL: '.
           05  WS-REG-SUB            PIC X(10).
           05  FILLER                PIC X(20) VALUE SPACES.
           05  WS-SUB-AMT            PIC $,$$$,$$$,$$$.99.
       
       01  WS-GRAND-TOTAL-LINE.
           05  FILLER                PIC X(5) VALUE SPACES.
           05  FILLER                PIC X(20) VALUE 'GRAND TOTAL: '.
           05  FILLER                PIC X(45) VALUE SPACES.
           05  WS-GRAND-AMT          PIC $,$$$,$$$,$$$.99.
       
       PROCEDURE DIVISION.
       MAIN-PARA.
           OPEN INPUT SALES-FILE
                OUTPUT REPORT-FILE
           
           PERFORM PRINT-HEADER
           PERFORM PROCESS-RECORDS
           PERFORM PRINT-REGION-SUBTOTAL
           PERFORM PRINT-GRAND-TOTAL
           
           CLOSE SALES-FILE
                 REPORT-FILE
           
           STOP RUN.
       
       PRINT-HEADER.
           ADD 1 TO WS-PAGE-NUM
           MOVE WS-PAGE-NUM TO WS-PAGE-OUT
           MOVE WS-HEADER TO REPORT-LINE
           WRITE REPORT-LINE AFTER ADVANCING PAGE
           
           MOVE SPACES TO REPORT-LINE
           WRITE REPORT-LINE AFTER ADVANCING 1
           
           MOVE WS-COL-HEADER TO REPORT-LINE
           WRITE REPORT-LINE AFTER ADVANCING 1
           
           MOVE ALL '-' TO REPORT-LINE
           WRITE REPORT-LINE AFTER ADVANCING 1
           
           MOVE 4 TO WS-LINE-CTR.
       
       CHECK-PAGE-BREAK.
           IF WS-LINE-CTR >= WS-MAX-LINES
               PERFORM PRINT-HEADER
           END-IF.
       
       PROCESS-RECORDS.
           PERFORM UNTIL END-OF-FILE
               READ SALES-FILE
                   AT END
                       SET END-OF-FILE TO TRUE
                   NOT AT END
                       PERFORM CHECK-CONTROL-BREAK
                       PERFORM PRINT-DETAIL
                       PERFORM ACCUMULATE
                       MOVE SALE-REGION TO WS-PREV-REGION
               END-READ
           END-PERFORM.
       
       CHECK-CONTROL-BREAK.
           IF WS-PREV-REGION NOT = SPACES
               IF SALE-REGION NOT = WS-PREV-REGION
                   PERFORM PRINT-REGION-SUBTOTAL
                   MOVE 0 TO WS-REGION-TOT
               END-IF
           END-IF.
       
       PRINT-DETAIL.
           PERFORM CHECK-PAGE-BREAK
           
           MOVE SALE-DATE TO WS-DATE-OUT
           MOVE SALE-REGION TO WS-REG-OUT
           MOVE SALE-AMOUNT TO WS-AMT-OUT
           MOVE SALE-REP TO WS-REP-OUT
           
           MOVE WS-DETAIL TO REPORT-LINE
           WRITE REPORT-LINE AFTER ADVANCING 1
           ADD 1 TO WS-LINE-CTR.
       
       ACCUMULATE.
           ADD SALE-AMOUNT TO WS-REGION-TOT
           ADD SALE-AMOUNT TO WS-GRAND-TOT.
       
       PRINT-REGION-SUBTOTAL.
           PERFORM CHECK-PAGE-BREAK
           
           MOVE SPACES TO REPORT-LINE
           WRITE REPORT-LINE AFTER ADVANCING 1
           ADD 1 TO WS-LINE-CTR
           
           MOVE WS-PREV-REGION TO WS-REG-SUB
           MOVE WS-REGION-TOT TO WS-SUB-AMT
           MOVE WS-SUBTOTAL TO REPORT-LINE
           WRITE REPORT-LINE AFTER ADVANCING 1
           ADD 1 TO WS-LINE-CTR
           
           MOVE ALL '-' TO REPORT-LINE
           WRITE REPORT-LINE AFTER ADVANCING 1
           ADD 1 TO WS-LINE-CTR.
       
       PRINT-GRAND-TOTAL.
           PERFORM CHECK-PAGE-BREAK
           
           MOVE SPACES TO REPORT-LINE
           WRITE REPORT-LINE AFTER ADVANCING 1
           ADD 1 TO WS-LINE-CTR
           
           MOVE ALL '=' TO REPORT-LINE
           WRITE REPORT-LINE AFTER ADVANCING 1
           ADD 1 TO WS-LINE-CTR
           
           MOVE WS-GRAND-TOT TO WS-GRAND-AMT
           MOVE WS-GRAND-TOTAL-LINE TO REPORT-LINE
           WRITE REPORT-LINE AFTER ADVANCING 1
           ADD 1 TO WS-LINE-CTR.

Best Practices for Report Generation

Follow these best practices for professional, maintainable reports:

1. Design First

Design your report layout on paper or in a document before coding. Define:

  • Column positions and widths
  • Header and footer content
  • Control break levels
  • Total and subtotal locations
  • Page layout and margins

2. Use Consistent Formatting

Maintain consistent formatting throughout the report:

  • Align columns consistently
  • Use the same number formatting for similar fields
  • Maintain consistent spacing
  • Use standard separators (dashes, equals signs)

3. Handle Edge Cases

Consider and handle edge cases:

  • Empty input files (no data to report)
  • Very long data values (truncate or wrap)
  • Negative numbers (proper sign display)
  • Zero values (display appropriately)
  • Page breaks in the middle of groups

4. Validate Before Printing

cobol
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       VALIDATE-AND-PRINT.
           IF SALE-AMOUNT < 0
               DISPLAY 'WARNING: Negative amount for ' SALE-REGION
               MOVE 0 TO SALE-AMOUNT
           END-IF
           
           IF SALE-REGION = SPACES
               MOVE 'UNKNOWN' TO SALE-REGION
           END-IF
           
           PERFORM PRINT-DETAIL.

5. Document Report Layout

Document your report structure:

  • Report purpose and usage
  • Input file structure
  • Output format and layout
  • Control break logic
  • Calculation formulas
  • Special formatting rules

Explain Like I'm 5: Report Generation

Think of report generation like creating a school report card:

  • Header is like the report card header with school name, student name, and date
  • Detail lines are like individual grades for each subject
  • Control breaks are like grouping subjects by category (math, science, English) and showing category averages
  • Subtotals are like the average for each subject category
  • Grand total is like the overall GPA at the end
  • Page breaks are like starting a new page when you run out of room
  • Formatting is like making sure everything is neat, aligned, and easy to read

Just like a report card organizes grades into a readable format, COBOL report generation organizes data into a professional, readable document!

Practice Exercises

Complete these exercises to reinforce your understanding:

Exercise 1: Basic Report

Create a simple report that reads customer records (ID, name, balance) and prints a formatted report with headers, detail lines, and a grand total of all balances.

Exercise 2: Control Breaks

Create a sales report grouped by region. Include detail lines for each sale, subtotals for each region, and a grand total. Handle control breaks properly.

Exercise 3: Page Breaks

Enhance your report to handle page breaks. Print headers on each page, track page numbers, and ensure subtotals and grand totals don't get split across pages.

Exercise 4: Number Formatting

Create a financial report with properly formatted currency amounts, percentages, and signed numbers. Use various editing characters to format different types of numeric data.

Exercise 5: Multi-Level Control Breaks

Create a report with multiple control break levels: region, then department, then product. Print subtotals at each level and a grand total at the end.

Test Your Knowledge

1. What is a control break in COBOL report generation?

  • A page break
  • When a control field value changes, signaling a new group
  • An error in the report
  • A line break in the output

2. When should you print report headers?

  • Only at the beginning of the report
  • At the beginning and at each page break
  • After every detail line
  • Only in the footer

3. How do you format a number as currency in COBOL?

  • Use the CURRENCY keyword
  • Use editing characters like $ and , in the PICTURE clause
  • Use a special FORMAT statement
  • COBOL cannot format currency

4. What is the difference between detail lines and summary lines?

  • There is no difference
  • Detail lines show individual records, summary lines show totals
  • Detail lines are longer
  • Summary lines are printed first

5. How do you handle page breaks in a COBOL report?

  • COBOL handles it automatically
  • Track line count and print footer/header when maximum lines reached
  • Use a special PAGE BREAK statement
  • Page breaks are not possible in COBOL

6. When should you print grand totals in a report?

  • At the beginning
  • After each detail line
  • At the end, after all records are processed
  • In the header

Related Concepts

Related Concepts

Report Writing

Learn about COBOL report writing techniques

Output Formatting

Understanding output formatting in COBOL

File Operations

Learn about file I/O for report output

Control Structures

Understanding control flow for report logic

Related Pages