COBOL Tutorial

REPORT-WRITER - COBOL Report Writer

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Overview

COBOL Report Writer lets you declare the shape of a report once and then simply GENERATElines. It prints page headings, details, footings, and control breaks for you.

🖨️ Analogy

Think of a bakery template for cake boxes. You design the template (REPORT SECTION), then every cake (record) is packaged identically by the machine (Report Writer).

Syntax and Usage

Defining a Report

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DATA DIVISION.
REPORT SECTION.
RD  SALES-RPT
    CONTROLS ARE CUST-ID
    PAGE LIMIT IS 60 LINES
    HEADING 1.
01  PAGE-HEADING TYPE PAGE HEADING.
    05  FILLER PIC X(40) VALUE 'SALES REPORT'.
01  CUST-HEADING TYPE CONTROL HEADING CUST-ID.
    05  FILLER PIC X(12) VALUE 'CUSTOMER: '.
    05  CUST-ID-OUT PIC X(10).
01  DETAIL-LINE TYPE DETAIL.
    05  ITEM PIC X(20).
    05  QTY  PIC 9(5).
    05  AMT  PIC 9(7)V99 SUM.
01  CUST-FOOT TYPE CONTROL FOOTING CUST-ID.
    05  FILLER PIC X(12) VALUE 'CUST TOTAL:'.
    05  CUST-TOTAL PIC 9(9)V99.
01  PAGE-FOOT TYPE PAGE FOOTING.
    05  FILLER PIC X(10) VALUE 'Page:'.
    05  PAGE-NO PIC 9(5).

RD defines the report. Groups (PAGE HEADING/FOOTING, CONTROL HEADING/FOOTING, DETAIL) describe printed lines.

Producing the Report

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PROCEDURE DIVISION.
OPEN INPUT SALES-FILE
OPEN OUTPUT REPORT-FILE
INIT-REPORT.
    MOVE 0 TO PAGE-NO
READ-LOOP.
    READ SALES-FILE AT END GO TO FINISH.
    MOVE CUST-ID-IN TO CUST-ID-OUT
    MOVE ITEM-IN TO ITEM
    MOVE QTY-IN  TO QTY
    MOVE AMT-IN  TO AMT
    GENERATE SALES-RPT
    GO TO READ-LOOP.
FINISH.
    CLOSE SALES-FILE REPORT-FILE
    STOP RUN.

GENERATE triggers the next logical group based on control breaks and page limits.

Practical Examples

Control Break Totals

Accumulate AMT with SUM, print in CONTROL FOOTING when CUST-ID changes.

Non-Code Example

Store sales are grouped by customer
Each page prints a heading with the report title
When the customer changes, a subtotal line prints
Page footer shows the current page number

Best Practices and Pitfalls

Best Practices

Keep detail lines narrow enough for target printers
Use SUM and CONTROL groups instead of manual totals
Document page limits and margins
Test with edge cases: last page, empty groups

Common Mistakes

Mistake	Problem	Fix
Manual totals everywhere	Duplicated logic	Use SUM and control break groups
Ignoring page size	Truncated lines	Match PAGE LIMIT to device

Quick Reference

Feature	Usage	Example
Report definition	REPORT SECTION / RD	RD SALES-RPT ...
Generate output	GENERATE report-name	GENERATE SALES-RPT
Control breaks	CONTROLS ARE field	CONTROLS ARE CUST-ID

Test Your Knowledge

1. What COBOL division contains Report Writer definitions?

IDENTIFICATION
ENVIRONMENT
DATA (REPORT SECTION)
PROCEDURE

2. Which statement produces output for a report?

DISPLAY
WRITE
GENERATE report-name
PRINT

3. Which groups commonly exist in a report?

PAGE HEADING / DETAIL / PAGE FOOTING
ENV HEADING / DATA HEADING
CLASS HEADING / OBJECT FOOTING
FILE HEADING / FILE FOOTING

4. How are control breaks handled?

With PERFORM ONLY
With CONTROL clause and CONTROL HEADING/FOOTING
With ACCEPT
With MOVE

5. Which counters are frequently used alongside Report Writer?

LINE-COUNTER, PAGE-COUNTER
PIXEL-COUNTER
CACHE-COUNTER
INDEX-COUNTER

Frequently Asked Questions

Related Concepts

PAGE-COUNTER

Managing page numbers.

LINE-COUNTER

Lines per page and pagination.

WRITE/AFTER ADVANCING

Manual page control.

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