COBOL Tutorial

COBOL LINE-COUNTER Special Register - Quick Reference

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Overview

The LINE-COUNTER special register is used in COBOL to track the current line number on a page during report generation. It works in conjunction with the LINAGE clause and LINAGE-COUNTER to provide automatic page formatting and line counting capabilities.

Purpose and Usage

Line tracking - Automatically tracks current line number on page
Page formatting - Works with LINAGE clause for page layout
Report generation - Essential for formatted report output
Automatic management - System-managed special register
Page breaks - Automatically resets when new page begins

LINE-COUNTER Concept

Page 1: LINE-COUNTER = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10...

Page Break: LINE-COUNTER resets to 1

Page 2: LINE-COUNTER = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10...

Automatic line counting within page boundaries

LINE-COUNTER automatically tracks line numbers and resets on page breaks.

Syntax and Usage

LINE-COUNTER is a special register that can be used directly in COBOL statements without declaration. It works with the LINAGE clause for proper page formatting.

Basic Syntax

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* LINE-COUNTER is used directly as a special register
* No declaration needed - it's built into COBOL
 
* Example usage in conditional statements
IF LINE-COUNTER > 50
    PERFORM WRITE-HEADER
END-IF
 
* Example usage in calculations
COMPUTE REMAINING-LINES = LINAGE-COUNTER - LINE-COUNTER
 
* Example usage in display statements
DISPLAY "Current line: " LINE-COUNTER
 
* Example usage with LINAGE clause
FD  REPORT-FILE
    LINAGE IS 60 LINES
    WITH FOOTING AT 55
    LINES AT TOP 5
    LINES AT BOTTOM 5.

LINE-COUNTER is a built-in special register that requires no declaration.

Complete Example

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* Complete example using LINE-COUNTER
       IDENTIFICATION DIVISION.
       PROGRAM-ID. LINE-COUNTER-DEMO.
       
       ENVIRONMENT DIVISION.
       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
           SELECT REPORT-FILE ASSIGN TO "REPORT.TXT"
                  ORGANIZATION IS LINE SEQUENTIAL.
       
       DATA DIVISION.
       FILE SECTION.
       FD  REPORT-FILE
           LINAGE IS 60 LINES
           WITH FOOTING AT 55
           LINES AT TOP 5
           LINES AT BOTTOM 5.
       
       01  REPORT-LINE.
           05  LINE-CONTENT    PIC X(80).
       
       WORKING-STORAGE SECTION.
       01  DATA-RECORD.
           05  RECORD-ID       PIC 9(6).
           05  RECORD-NAME     PIC X(30).
           05  RECORD-VALUE    PIC 9(8)V99.
       01  PAGE-NUMBER         PIC 9(3) VALUE 1.
       01  REMAINING-LINES     PIC 9(2).
       
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           OPEN OUTPUT REPORT-FILE
           PERFORM WRITE-REPORT-HEADER
           PERFORM PROCESS-DATA
           CLOSE REPORT-FILE
           STOP RUN.
       
       WRITE-REPORT-HEADER.
           * Write header at top of page
           MOVE "REPORT HEADER - PAGE " TO LINE-CONTENT
           MOVE PAGE-NUMBER TO LINE-CONTENT(20:3)
           WRITE REPORT-LINE
           * LINE-COUNTER is now 1
           
           MOVE "DATE: " TO LINE-CONTENT
           MOVE FUNCTION CURRENT-DATE TO LINE-CONTENT(7:8)
           WRITE REPORT-LINE
           * LINE-COUNTER is now 2.
       
       PROCESS-DATA.
           * Process data records
           PERFORM UNTIL END-OF-DATA
               READ DATA-FILE
                   AT END SET END-OF-DATA TO TRUE
               END-READ
               
               * Check if we need a new page
               IF LINE-COUNTER > 50
                   PERFORM NEW-PAGE
               END-IF
               
               * Write data line
               PERFORM WRITE-DATA-LINE
           END-PERFORM.
       
       NEW-PAGE.
           * Start new page
           ADD 1 TO PAGE-NUMBER
           PERFORM WRITE-REPORT-HEADER
           * LINE-COUNTER is automatically reset to 1.
       
       WRITE-DATA-LINE.
           * Write data line
           MOVE RECORD-ID TO LINE-CONTENT(1:6)
           MOVE RECORD-NAME TO LINE-CONTENT(8:30)
           MOVE RECORD-VALUE TO LINE-CONTENT(40:10)
           WRITE REPORT-LINE
           * LINE-COUNTER is automatically incremented.

This example shows how LINE-COUNTER is used with LINAGE for page formatting.

LINAGE Clause Integration

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* LINAGE clause with LINE-COUNTER
FD  REPORT-FILE
    LINAGE IS 60 LINES                    * Total lines per page
    WITH FOOTING AT 55                    * Footer starts at line 55
    LINES AT TOP 5                        * Header area (lines 1-5)
    LINES AT BOTTOM 5.                    * Footer area (lines 56-60)
 
* LINE-COUNTER behavior with this LINAGE:
* - Starts at 1 for each page
* - Increments with each WRITE statement
* - Resets to 1 when page is full (line 60)
* - Can be used to check current position
 
* Example usage:
IF LINE-COUNTER = 1
    PERFORM WRITE-PAGE-HEADER
END-IF
 
IF LINE-COUNTER = 55
    PERFORM WRITE-PAGE-FOOTER
END-IF
 
IF LINE-COUNTER > 50
    PERFORM NEW-PAGE
END-IF

The LINAGE clause defines page layout parameters that LINE-COUNTER works within.

Common Use Cases

LINE-COUNTER is essential in various scenarios where proper page formatting and line tracking are critical for report generation.

Report Generation

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* Report generation with LINE-COUNTER
       IDENTIFICATION DIVISION.
       PROGRAM-ID. REPORT-GENERATOR.
       
       ENVIRONMENT DIVISION.
       INPUT-OUTPUT SECTION.
       FILE-CONTROL.
           SELECT REPORT-FILE ASSIGN TO "SALES-REPORT.TXT"
                  ORGANIZATION IS LINE SEQUENTIAL.
       
       DATA DIVISION.
       FILE SECTION.
       FD  REPORT-FILE
           LINAGE IS 66 LINES
           WITH FOOTING AT 60
           LINES AT TOP 6
           LINES AT BOTTOM 6.
       
       01  REPORT-LINE.
           05  LINE-CONTENT    PIC X(132).
       
       WORKING-STORAGE SECTION.
       01  SALES-RECORD.
           05  SALES-DATE      PIC 9(8).
           05  SALES-AMOUNT    PIC 9(8)V99.
           05  SALES-REGION    PIC X(20).
       01  PAGE-NUMBER         PIC 9(3) VALUE 1.
       01  TOTAL-SALES         PIC 9(10)V99 VALUE ZERO.
       
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           OPEN OUTPUT REPORT-FILE
           PERFORM WRITE-REPORT-HEADER
           PERFORM PROCESS-SALES-DATA
           PERFORM WRITE-REPORT-FOOTER
           CLOSE REPORT-FILE
           STOP RUN.
       
       WRITE-REPORT-HEADER.
           * Write header only at top of page
           IF LINE-COUNTER = 1
               MOVE "SALES REPORT" TO LINE-CONTENT
               WRITE REPORT-LINE
               MOVE "PAGE " TO LINE-CONTENT(1:5)
               MOVE PAGE-NUMBER TO LINE-CONTENT(6:3)
               WRITE REPORT-LINE
               MOVE SPACES TO LINE-CONTENT
               WRITE REPORT-LINE
           END-IF.
       
       PROCESS-SALES-DATA.
           * Process sales data with page breaks
           PERFORM UNTIL END-OF-SALES-DATA
               READ SALES-FILE
                   AT END SET END-OF-SALES-DATA TO TRUE
               END-READ
               
               * Check if page is getting full
               IF LINE-COUNTER > 55
                   PERFORM NEW-PAGE
               END-IF
               
               * Write sales data
               PERFORM WRITE-SALES-LINE
           END-PERFORM.
       
       NEW-PAGE.
           * Start new page
           ADD 1 TO PAGE-NUMBER
           PERFORM WRITE-REPORT-HEADER.
       
       WRITE-SALES-LINE.
           * Write sales data line
           MOVE SALES-DATE TO LINE-CONTENT(1:8)
           MOVE SALES-AMOUNT TO LINE-CONTENT(10:10)
           MOVE SALES-REGION TO LINE-CONTENT(22:20)
           WRITE REPORT-LINE
           ADD SALES-AMOUNT TO TOTAL-SALES.

Report generation uses LINE-COUNTER for proper page formatting and headers.

Page Break Management

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* Page break management with LINE-COUNTER
       IDENTIFICATION DIVISION.
       PROGRAM-ID. PAGE-BREAK-MANAGER.
       
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  CURRENT-LINE       PIC 9(2).
       01  LINES-PER-PAGE     PIC 9(2) VALUE 60.
       01  FOOTER-START       PIC 9(2) VALUE 55.
       01  HEADER-LINES       PIC 9(2) VALUE 5.
       
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           * Check current line position
           MOVE LINE-COUNTER TO CURRENT-LINE
           
           * Determine if page break is needed
           IF CURRENT-LINE >= FOOTER-START
               PERFORM FORCE-PAGE-BREAK
           END-IF
           
           * Check if we're at the top of a page
           IF CURRENT-LINE <= HEADER-LINES
               PERFORM WRITE-HEADER
           END-IF
           
           STOP RUN.
       
       FORCE-PAGE-BREAK.
           * Force a page break
           WRITE REPORT-LINE FROM SPACES
           * This will cause LINE-COUNTER to reset to 1
           DISPLAY "Page break occurred, LINE-COUNTER reset to: " LINE-COUNTER.
       
       WRITE-HEADER.
           * Write header information
           DISPLAY "Writing header at line: " LINE-COUNTER
           * Write header content here.

Page break management uses LINE-COUNTER to determine when to start new pages.

Conditional Formatting

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* Conditional formatting based on LINE-COUNTER
       IDENTIFICATION DIVISION.
       PROGRAM-ID. CONDITIONAL-FORMATTER.
       
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  FORMAT-TYPE        PIC X(10).
       01  LINE-POSITION      PIC 9(2).
       
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           * Get current line position
           MOVE LINE-COUNTER TO LINE-POSITION
           
           * Apply conditional formatting based on line position
           EVALUATE LINE-POSITION
               WHEN 1
                   MOVE "HEADER" TO FORMAT-TYPE
                   PERFORM APPLY-HEADER-FORMAT
               WHEN 2 THRU 5
                   MOVE "SUBHEADER" TO FORMAT-TYPE
                   PERFORM APPLY-SUBHEADER-FORMAT
               WHEN 55 THRU 60
                   MOVE "FOOTER" TO FORMAT-TYPE
                   PERFORM APPLY-FOOTER-FORMAT
               WHEN OTHER
                   MOVE "BODY" TO FORMAT-TYPE
                   PERFORM APPLY-BODY-FORMAT
           END-EVALUATE
           
           STOP RUN.
       
       APPLY-HEADER-FORMAT.
           * Apply header formatting
           DISPLAY "Applying header format at line: " LINE-COUNTER.
       
       APPLY-SUBHEADER-FORMAT.
           * Apply subheader formatting
           DISPLAY "Applying subheader format at line: " LINE-COUNTER.
       
       APPLY-FOOTER-FORMAT.
           * Apply footer formatting
           DISPLAY "Applying footer format at line: " LINE-COUNTER.
       
       APPLY-BODY-FORMAT.
           * Apply body formatting
           DISPLAY "Applying body format at line: " LINE-COUNTER.

Conditional formatting uses LINE-COUNTER to apply different styles based on line position.

Best Practices and Tips

Following these best practices ensures effective use of LINE-COUNTER in COBOL applications.

LINE-COUNTER Best Practices

Use with LINAGE - Always use LINE-COUNTER with LINAGE clause for proper page formatting
Check before writing - Check LINE-COUNTER before writing to avoid page overflow
Plan page breaks - Plan page breaks before reaching the footer area
Don't modify directly - Never try to modify LINE-COUNTER directly
Test page boundaries - Test your program with different page sizes
Document assumptions - Document any assumptions about page layout

Common LINAGE Configurations

Page Type	LINAGE Configuration	Use Case
Standard Report	66 LINES, FOOTING AT 60	Business reports
Compact Report	50 LINES, FOOTING AT 45	Dense data reports
Detailed Report	80 LINES, FOOTING AT 75	Detailed analysis reports
Letter Format	60 LINES, FOOTING AT 55	Letter-style documents
Invoice Format	40 LINES, FOOTING AT 35	Invoice and billing documents

Performance Considerations

Minimal overhead - LINE-COUNTER has minimal performance impact
Automatic management - System handles line counting automatically
Efficient page breaks - Page breaks are handled efficiently by the system
Memory usage - LINE-COUNTER uses minimal memory
I/O optimization - Proper use can optimize I/O operations
Testing - Test with large datasets to ensure performance

When to Use LINE-COUNTER

Use Case	LINE-COUNTER Suitability	Reasoning
Report generation	Excellent	Essential for proper page formatting
Page break management	Excellent	Automatic page break handling
Header/footer positioning	Excellent	Precise positioning control
Data processing	Poor	Not designed for data processing
File operations	Poor	Not designed for file operations

LINE-COUNTER Quick Reference

Operation	Syntax	Example
Check current line	IF LINE-COUNTER condition	IF LINE-COUNTER > 50
Page break check	IF LINE-COUNTER >= footer-line	IF LINE-COUNTER >= 55
Header positioning	IF LINE-COUNTER = 1	IF LINE-COUNTER = 1
Footer positioning	IF LINE-COUNTER = footer-line	IF LINE-COUNTER = 55
Display current line	DISPLAY LINE-COUNTER	DISPLAY "Line: " LINE-COUNTER

Test Your Knowledge

1. What is the primary purpose of the LINE-COUNTER special register in COBOL?

To count characters in a string
To track line numbers for report generation and page formatting
To count records in a file
To track program execution steps

2. How is LINE-COUNTER typically used in COBOL programs?

As a data field in calculations
In conjunction with LINAGE and LINAGE-COUNTER for page formatting
To count file records
To track program performance

3. What happens to LINE-COUNTER when a page break occurs?

It continues counting from the previous value
It is automatically reset to 1
It stops counting
It becomes undefined

4. Which COBOL clause is most closely related to LINE-COUNTER?

OCCURS clause
LINAGE clause
REDEFINES clause
PICTURE clause

5. How do you access the current value of LINE-COUNTER in a COBOL program?

By declaring it as a data item
By using it directly as a special register
By calling a system function
By reading it from a file

COBOL Tutorial

COBOL LINE-COUNTER Special Register - Quick Reference

Overview

Purpose and Usage

LINE-COUNTER Concept

Syntax and Usage

Basic Syntax

Complete Example

LINAGE Clause Integration

Common Use Cases

Report Generation

Page Break Management

Conditional Formatting

Best Practices and Tips

LINE-COUNTER Best Practices

Common LINAGE Configurations

Performance Considerations

When to Use LINE-COUNTER

LINE-COUNTER Quick Reference

Test Your Knowledge

Frequently Asked Questions

Related Concepts

LINAGE Clause

LINAGE-COUNTER Special Register

Report Generation

File Description (FD)

Page Formatting

Related Pages

COBOL Tutorial

COBOL LINE-COUNTER Special Register - Quick Reference

Overview

Purpose and Usage

LINE-COUNTER Concept

Syntax and Usage

Basic Syntax

Complete Example

LINAGE Clause Integration

Common Use Cases

Report Generation

Page Break Management

Conditional Formatting

Best Practices and Tips

LINE-COUNTER Best Practices

Common LINAGE Configurations

Performance Considerations

When to Use LINE-COUNTER

LINE-COUNTER Quick Reference

Test Your Knowledge

Frequently Asked Questions

What is the difference between LINE-COUNTER and LINAGE-COUNTER?

How do you use LINE-COUNTER with the LINAGE clause?

Can you modify the value of LINE-COUNTER directly?

How does LINE-COUNTER handle different page sizes?

What are common use cases for LINE-COUNTER in COBOL applications?

Related Concepts

LINAGE Clause

LINAGE-COUNTER Special Register

Report Generation

File Description (FD)

Page Formatting

Related Pages