COBOL Tutorial

COBOL LINE Clause - Quick Reference

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Overview

The LINE clause is a positioning clause used in COBOL screen handling to specify the vertical position (row number) where text or input fields should appear on the terminal screen. It is commonly used with DISPLAY and ACCEPT statements to control cursor positioning.

Purpose and Usage

Vertical positioning - Controls which row (line) text appears on
Screen layout control - Enables precise placement of screen elements
User interface design - Creates organized, readable screen layouts
Cursor management - Positions cursor for input and output operations
Menu and form design - Essential for creating structured user interfaces

Terminal Screen Coordinates

┌─────────────────────────────────────────────────────────────────────────────┐

│ Line 1 │ │

│ Line 2 │ │

│ Line 3 │ │

│ Line 4 │ │

│ Line 5 │ │

│ ... │ │

│ Line 23 │ │

│ Line 24 │ │

└─────────┴─────────────────────────────────────────────────────────────────┘

Column: 1 10 20 30 40 50 60 70 80

Standard terminal screens typically have 24 or 25 lines, with LINE 1 at the top and LINE 24/25 at the bottom.

Syntax

The LINE clause follows a specific syntax pattern and can be used in various contexts within COBOL screen handling statements.

Basic Syntax

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* Basic LINE clause syntax
AT LINE line-number
 
* Examples
AT LINE 5
AT LINE 10
AT LINE 24
 
* With COLUMN clause for complete positioning
AT LINE line-number AT COLUMN column-number
 
* Examples of complete positioning
AT LINE 5 AT COLUMN 10
AT LINE 10 AT COLUMN 20
AT LINE 1 AT COLUMN 1

The AT keyword is required, and line-number must be a positive integer.

Valid Line Number Ranges

Terminal Type	Line Range	Common Usage
Standard Terminal	1 to 24	Most common terminal type
Extended Terminal	1 to 25	Some modern terminals
Large Terminal	1 to 43	High-resolution terminals
PC Terminal	1 to 50	PC-based terminal emulators

Using Variables and Expressions

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* Using variables with LINE clause
AT LINE CURRENT-LINE AT COLUMN 10
 
* Using arithmetic expressions
AT LINE (LINE-NUMBER + 2) AT COLUMN 10
AT LINE (START-LINE + OFFSET) AT COLUMN 15
 
* Using data names
AT LINE MENU-LINE AT COLUMN 20
AT LINE HEADER-LINE AT COLUMN 1
 
* Examples with working storage
WORKING-STORAGE SECTION.
01  CURRENT-LINE      PIC 9(2) VALUE 5.
01  MENU-LINE         PIC 9(2) VALUE 8.
01  HEADER-LINE       PIC 9(2) VALUE 1.
01  LINE-OFFSET       PIC 9(2) VALUE 2.
 
PROCEDURE DIVISION.
    DISPLAY "Header" AT LINE HEADER-LINE AT COLUMN 1
    DISPLAY "Menu" AT LINE MENU-LINE AT COLUMN 10
    DISPLAY "Content" AT LINE (CURRENT-LINE + LINE-OFFSET) AT COLUMN 5

Variables and expressions provide dynamic positioning capabilities.

Usage in DISPLAY Statements

The LINE clause is commonly used in DISPLAY statements to control where output text appears on the screen.

Basic DISPLAY with LINE

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* Simple DISPLAY with LINE positioning
DISPLAY "Hello World" AT LINE 5 AT COLUMN 10
 
* Multiple positioned displays
DISPLAY "Title" AT LINE 1 AT COLUMN 20
DISPLAY "Subtitle" AT LINE 2 AT COLUMN 20
DISPLAY "Content" AT LINE 5 AT COLUMN 10
 
* Display with attributes
DISPLAY "Important Message" AT LINE 10 AT COLUMN 5 WITH HIGHLIGHT
DISPLAY "Error" AT LINE 15 AT COLUMN 5 WITH REVERSE-VIDEO
 
* Display variables at specific positions
DISPLAY "Customer ID: " AT LINE 8 AT COLUMN 10
DISPLAY CUSTOMER-ID AT LINE 8 AT COLUMN 25

LINE positioning ensures consistent screen layouts and professional appearance.

Creating Menu Layouts

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* Menu layout using LINE positioning
DISPLAY "CUSTOMER MANAGEMENT SYSTEM" AT LINE 1 AT COLUMN 15 WITH HIGHLIGHT
DISPLAY "================================================" AT LINE 2 AT COLUMN 1
DISPLAY "MAIN MENU" AT LINE 4 AT COLUMN 20
DISPLAY "---------" AT LINE 5 AT COLUMN 20
DISPLAY "1. Add Customer" AT LINE 7 AT COLUMN 20
DISPLAY "2. View Customer" AT LINE 8 AT COLUMN 20
DISPLAY "3. Update Customer" AT LINE 9 AT COLUMN 20
DISPLAY "4. Delete Customer" AT LINE 10 AT COLUMN 20
DISPLAY "5. Exit" AT LINE 11 AT COLUMN 20
DISPLAY "Enter your choice: " AT LINE 13 AT COLUMN 20
DISPLAY "================================================" AT LINE 15 AT COLUMN 1
 
* Status message area
DISPLAY "Status: " AT LINE 20 AT COLUMN 10
DISPLAY STATUS-MESSAGE AT LINE 20 AT COLUMN 20

Structured layouts improve user experience and readability.

Screen Clearing and Positioning

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* Clear screen and position at top
DISPLAY SPACES AT LINE 1 AT COLUMN 1
 
* Clear specific areas
DISPLAY SPACES AT LINE 10 AT COLUMN 1
DISPLAY SPACES AT LINE 11 AT COLUMN 1
DISPLAY SPACES AT LINE 12 AT COLUMN 1
 
* Position cursor after clearing
DISPLAY "New content" AT LINE 5 AT COLUMN 10
 
* Clear status area
DISPLAY SPACES AT LINE 20 AT COLUMN 1
DISPLAY "New status message" AT LINE 20 AT COLUMN 10
 
* Clear entire screen (alternative method)
DISPLAY SPACES AT LINE 1 AT COLUMN 1 ERASE

Screen clearing ensures clean displays and prevents overlapping text.

Usage in ACCEPT Statements

The LINE clause is also used in ACCEPT statements to position input fields on the screen for user data entry.

Basic ACCEPT with LINE

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* Simple ACCEPT with LINE positioning
ACCEPT USER-NAME AT LINE 5 AT COLUMN 20
 
* ACCEPT with prompt and positioning
ACCEPT CUSTOMER-ID 
    AT LINE 8 AT COLUMN 25
    PROMPT "Customer ID: "
 
* Multiple positioned accepts
ACCEPT CUSTOMER-ID AT LINE 8 AT COLUMN 25 PROMPT "Customer ID: "
ACCEPT CUSTOMER-NAME AT LINE 9 AT COLUMN 25 PROMPT "Customer Name: "
ACCEPT CUSTOMER-ADDRESS AT LINE 10 AT COLUMN 25 PROMPT "Address: "
 
* ACCEPT with attributes
ACCEPT PASSWORD 
    AT LINE 12 AT COLUMN 25
    PROMPT "Password: "
    WITH SECURE

LINE positioning in ACCEPT creates organized input forms.

Form Layout with ACCEPT

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* Complete form layout
DISPLAY "CUSTOMER ENTRY FORM" AT LINE 1 AT COLUMN 15 WITH HIGHLIGHT
DISPLAY "================================================" AT LINE 2 AT COLUMN 1
 
* Form fields with positioning
ACCEPT CUSTOMER-ID 
    AT LINE 5 AT COLUMN 25
    PROMPT "Customer ID: "
    REQUIRED AUTO-SKIP
 
ACCEPT CUSTOMER-NAME 
    AT LINE 6 AT COLUMN 25
    PROMPT "Customer Name: "
    REQUIRED AUTO-SKIP
 
ACCEPT CUSTOMER-ADDRESS 
    AT LINE 7 AT COLUMN 25
    PROMPT "Address: "
    AUTO-SKIP
 
ACCEPT CUSTOMER-PHONE 
    AT LINE 8 AT COLUMN 25
    PROMPT "Phone: "
    AUTO-SKIP
 
* Instructions at bottom
DISPLAY "Press ENTER to save, ESC to cancel" AT LINE 12 AT COLUMN 10
DISPLAY "================================================" AT LINE 14 AT COLUMN 1

Well-structured forms improve data entry efficiency and reduce errors.

Dynamic Positioning with Variables

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WORKING-STORAGE SECTION.
01  CURRENT-LINE      PIC 9(2) VALUE 5.
01  FIELD-OFFSET      PIC 9(2) VALUE 2.
 
PROCEDURE DIVISION.
    * Position first field
    ACCEPT CUSTOMER-ID 
        AT LINE CURRENT-LINE AT COLUMN 25
        PROMPT "Customer ID: "
    
    * Position subsequent fields dynamically
    ADD FIELD-OFFSET TO CURRENT-LINE
    ACCEPT CUSTOMER-NAME 
        AT LINE CURRENT-LINE AT COLUMN 25
        PROMPT "Customer Name: "
    
    ADD FIELD-OFFSET TO CURRENT-LINE
    ACCEPT CUSTOMER-ADDRESS 
        AT LINE CURRENT-LINE AT COLUMN 25
        PROMPT "Address: "
    
    ADD FIELD-OFFSET TO CURRENT-LINE
    ACCEPT CUSTOMER-PHONE 
        AT LINE CURRENT-LINE AT COLUMN 25
        PROMPT "Phone: "

Dynamic positioning allows flexible form layouts and easy maintenance.

Usage in SCREEN SECTION

The LINE clause is extensively used in the SCREEN SECTION to define the layout and positioning of screen elements in formatted screens.

SCREEN SECTION with LINE

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DATA DIVISION.
SCREEN SECTION.
01  CUSTOMER-SCREEN.
    05  LINE 1  COLUMN 1  VALUE "================================================".
    05  LINE 2  COLUMN 15 VALUE "CUSTOMER MANAGEMENT SYSTEM"
        HIGHLIGHT.
    05  LINE 3  COLUMN 1  VALUE "================================================".
    05  LINE 5  COLUMN 10 VALUE "Customer ID: ".
    05  LINE 5  COLUMN 25 PIC X(10) TO CUSTOMER-ID
        REQUIRED AUTO-SKIP.
    05  LINE 6  COLUMN 10 VALUE "Customer Name: ".
    05  LINE 6  COLUMN 25 PIC X(30) TO CUSTOMER-NAME
        REQUIRED AUTO-SKIP.
    05  LINE 7  COLUMN 10 VALUE "Address: ".
    05  LINE 7  COLUMN 25 PIC X(40) TO CUSTOMER-ADDRESS
        AUTO-SKIP.
    05  LINE 8  COLUMN 10 VALUE "Phone: ".
    05  LINE 8  COLUMN 25 PIC X(15) TO CUSTOMER-PHONE
        AUTO-SKIP.
    05  LINE 10 COLUMN 10 VALUE "Status: ".
    05  LINE 10 COLUMN 20 PIC X(40) FROM STATUS-MESSAGE.
    05  LINE 12 COLUMN 10 VALUE "Press ENTER to save, ESC to cancel".
    05  LINE 14 COLUMN 1  VALUE "================================================".

SCREEN SECTION provides structured screen layouts with precise positioning.

Menu Screen Definition

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01  MENU-SCREEN.
    05  LINE 1  COLUMN 1  VALUE "================================================".
    05  LINE 2  COLUMN 15 VALUE "MAIN MENU"
        HIGHLIGHT.
    05  LINE 3  COLUMN 1  VALUE "================================================".
    05  LINE 5  COLUMN 20 VALUE "1. Add Customer".
    05  LINE 6  COLUMN 20 VALUE "2. View Customer".
    05  LINE 7  COLUMN 20 VALUE "3. Update Customer".
    05  LINE 8  COLUMN 20 VALUE "4. Delete Customer".
    05  LINE 9  COLUMN 20 VALUE "5. Search Customer".
    05  LINE 10 COLUMN 20 VALUE "6. Exit".
    05  LINE 12 COLUMN 20 VALUE "Enter your choice: ".
    05  LINE 12 COLUMN 40 PIC 9 TO MENU-CHOICE
        REQUIRED AUTO-SKIP.
    05  LINE 14 COLUMN 20 VALUE "----------------------------------------".
    05  LINE 16 COLUMN 20 VALUE "F1=Help  ESC=Exit".
    05  LINE 18 COLUMN 1  VALUE "================================================".

Menu screens provide clear navigation with consistent positioning.

Using Variables in SCREEN SECTION

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WORKING-STORAGE SECTION.
01  HEADER-LINE       PIC 9(2) VALUE 1.
01  MENU-START-LINE   PIC 9(2) VALUE 5.
01  STATUS-LINE       PIC 9(2) VALUE 20.
 
SCREEN SECTION.
01  DYNAMIC-SCREEN.
    05  LINE HEADER-LINE COLUMN 1 VALUE "================================================".
    05  LINE HEADER-LINE COLUMN 15 VALUE "DYNAMIC SCREEN"
        HIGHLIGHT.
    05  LINE (HEADER-LINE + 1) COLUMN 1 VALUE "================================================".
    05  LINE MENU-START-LINE COLUMN 20 VALUE "Menu Option 1".
    05  LINE (MENU-START-LINE + 1) COLUMN 20 VALUE "Menu Option 2".
    05  LINE (MENU-START-LINE + 2) COLUMN 20 VALUE "Menu Option 3".
    05  LINE STATUS-LINE COLUMN 10 VALUE "Status: ".
    05  LINE STATUS-LINE COLUMN 20 PIC X(40) FROM STATUS-MESSAGE.

Variables in SCREEN SECTION enable flexible, maintainable screen layouts.

Practical Examples

These practical examples demonstrate common usage patterns and techniques for the LINE clause in real-world COBOL applications.

Complete Customer Entry Program

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IDENTIFICATION DIVISION.
PROGRAM-ID. CUSTOMER-ENTRY.
 
ENVIRONMENT DIVISION.
 
DATA DIVISION.
WORKING-STORAGE SECTION.
01  CUSTOMER-ID        PIC X(10).
01  CUSTOMER-NAME      PIC X(30).
01  CUSTOMER-ADDRESS   PIC X(40).
01  CUSTOMER-PHONE     PIC X(15).
01  STATUS-MESSAGE     PIC X(40).
01  EXIT-FLAG          PIC X VALUE "N".
    88  EXIT-PROGRAM     VALUE "Y".
 
SCREEN SECTION.
01  CUSTOMER-ENTRY-SCREEN.
    05  LINE 1  COLUMN 1  VALUE "================================================".
    05  LINE 2  COLUMN 15 VALUE "CUSTOMER ENTRY FORM"
        HIGHLIGHT.
    05  LINE 3  COLUMN 1  VALUE "================================================".
    05  LINE 5  COLUMN 10 VALUE "Customer ID: ".
    05  LINE 5  COLUMN 25 PIC X(10) TO CUSTOMER-ID
        REQUIRED AUTO-SKIP.
    05  LINE 6  COLUMN 10 VALUE "Customer Name: ".
    05  LINE 6  COLUMN 25 PIC X(30) TO CUSTOMER-NAME
        REQUIRED AUTO-SKIP.
    05  LINE 7  COLUMN 10 VALUE "Address: ".
    05  LINE 7  COLUMN 25 PIC X(40) TO CUSTOMER-ADDRESS
        AUTO-SKIP.
    05  LINE 8  COLUMN 10 VALUE "Phone: ".
    05  LINE 8  COLUMN 25 PIC X(15) TO CUSTOMER-PHONE
        AUTO-SKIP.
    05  LINE 10 COLUMN 10 VALUE "Status: ".
    05  LINE 10 COLUMN 20 PIC X(40) FROM STATUS-MESSAGE.
    05  LINE 12 COLUMN 10 VALUE "Press ENTER to save, ESC to exit".
    05  LINE 14 COLUMN 1  VALUE "================================================".
 
PROCEDURE DIVISION.
MAIN-PROCESS.
    PERFORM UNTIL EXIT-PROGRAM
        PERFORM DISPLAY-CUSTOMER-FORM
        PERFORM PROCESS-CUSTOMER-DATA
    END-PERFORM
    STOP RUN.
 
DISPLAY-CUSTOMER-FORM.
    MOVE SPACES TO CUSTOMER-ID
    MOVE SPACES TO CUSTOMER-NAME
    MOVE SPACES TO CUSTOMER-ADDRESS
    MOVE SPACES TO CUSTOMER-PHONE
    MOVE SPACES TO STATUS-MESSAGE
    ACCEPT OMITTED FROM CUSTOMER-ENTRY-SCREEN.
 
PROCESS-CUSTOMER-DATA.
    IF CUSTOMER-ID NOT = SPACES AND CUSTOMER-NAME NOT = SPACES
        PERFORM SAVE-CUSTOMER
        MOVE "Customer saved successfully" TO STATUS-MESSAGE
        DISPLAY STATUS-MESSAGE AT LINE 10 AT COLUMN 20
    ELSE
        MOVE "Customer ID and Name are required" TO STATUS-MESSAGE
        DISPLAY STATUS-MESSAGE AT LINE 10 AT COLUMN 20
    END-IF.
 
SAVE-CUSTOMER.
    * Here you would add code to save to file or database
    DISPLAY "Saving customer data..." AT LINE 15 AT COLUMN 10.

This complete program demonstrates LINE clause usage in a practical application.

Multi-Screen Navigation

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WORKING-STORAGE SECTION.
01  MENU-CHOICE        PIC 9.
01  CURRENT-SCREEN     PIC 9 VALUE 1.
 
SCREEN SECTION.
01  MAIN-MENU-SCREEN.
    05  LINE 1  COLUMN 1  VALUE "================================================".
    05  LINE 2  COLUMN 15 VALUE "MAIN MENU"
        HIGHLIGHT.
    05  LINE 3  COLUMN 1  VALUE "================================================".
    05  LINE 5  COLUMN 20 VALUE "1. Customer Entry".
    05  LINE 6  COLUMN 20 VALUE "2. Customer Search".
    05  LINE 7  COLUMN 20 VALUE "3. Reports".
    05  LINE 8  COLUMN 20 VALUE "4. Exit".
    05  LINE 10 COLUMN 20 VALUE "Enter your choice: ".
    05  LINE 10 COLUMN 40 PIC 9 TO MENU-CHOICE
        REQUIRED AUTO-SKIP.
 
01  SEARCH-SCREEN.
    05  LINE 1  COLUMN 1  VALUE "================================================".
    05  LINE 2  COLUMN 15 VALUE "CUSTOMER SEARCH"
        HIGHLIGHT.
    05  LINE 3  COLUMN 1  VALUE "================================================".
    05  LINE 5  COLUMN 10 VALUE "Search by ID: ".
    05  LINE 5  COLUMN 25 PIC X(10) TO SEARCH-ID
        REQUIRED AUTO-SKIP.
    05  LINE 7  COLUMN 10 VALUE "Search by Name: ".
    05  LINE 7  COLUMN 25 PIC X(30) TO SEARCH-NAME
        AUTO-SKIP.
    05  LINE 9  COLUMN 10 VALUE "Press ENTER to search, ESC to return".
 
PROCEDURE DIVISION.
MAIN-PROCESS.
    PERFORM UNTIL EXIT-PROGRAM
        EVALUATE CURRENT-SCREEN
            WHEN 1
                PERFORM DISPLAY-MAIN-MENU
            WHEN 2
                PERFORM DISPLAY-SEARCH-SCREEN
            WHEN OTHER
                MOVE 1 TO CURRENT-SCREEN
        END-EVALUATE
    END-PERFORM
    STOP RUN.
 
DISPLAY-MAIN-MENU.
    ACCEPT OMITTED FROM MAIN-MENU-SCREEN
    EVALUATE MENU-CHOICE
        WHEN 1
            MOVE 2 TO CURRENT-SCREEN
        WHEN 2
            MOVE 3 TO CURRENT-SCREEN
        WHEN 4
            MOVE "Y" TO EXIT-FLAG
    END-EVALUATE.
 
DISPLAY-SEARCH-SCREEN.
    ACCEPT OMITTED FROM SEARCH-SCREEN
    IF SEARCH-ID NOT = SPACES
        PERFORM SEARCH-CUSTOMER
    END-IF
    MOVE 1 TO CURRENT-SCREEN.

Multi-screen applications use LINE positioning for consistent navigation.

Error Handling with LINE

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PROCEDURE DIVISION.
VALIDATE-CUSTOMER-DATA.
    MOVE "Y" TO VALID-FLAG
    
    * Validate Customer ID
    IF CUSTOMER-ID = SPACES OR CUSTOMER-ID = ZEROS
        MOVE "N" TO VALID-FLAG
        DISPLAY "Error: Customer ID is required" 
            AT LINE 15 AT COLUMN 10 WITH HIGHLIGHT
    END-IF
    
    * Validate Customer Name
    IF CUSTOMER-NAME = SPACES
        MOVE "N" TO VALID-FLAG
        DISPLAY "Error: Customer Name is required" 
            AT LINE 16 AT COLUMN 10 WITH HIGHLIGHT
    END-IF
    
    * Validate Phone Number
    IF CUSTOMER-PHONE NOT = SPACES
        IF CUSTOMER-PHONE NOT NUMERIC
            MOVE "N" TO VALID-FLAG
            DISPLAY "Error: Phone number must be numeric" 
                AT LINE 17 AT COLUMN 10 WITH HIGHLIGHT
        END-IF
    END-IF
    
    * Clear error messages if valid
    IF VALID-FLAG = "Y"
        DISPLAY SPACES AT LINE 15 AT COLUMN 10
        DISPLAY SPACES AT LINE 16 AT COLUMN 10
        DISPLAY SPACES AT LINE 17 AT COLUMN 10
        DISPLAY "Data validation successful" 
            AT LINE 15 AT COLUMN 10 WITH LOWLIGHT
    END-IF.

LINE positioning is essential for organized error message display.

Best Practices and Tips

Following these best practices ensures effective and maintainable use of the LINE clause in COBOL screen handling applications.

Line Positioning Best Practices

Use consistent spacing - Maintain 1-2 lines between screen elements
Reserve header lines - Use lines 1-3 for titles and headers
Use bottom lines for status - Reserve lines 20-24 for messages and navigation
Avoid overlapping - Ensure sufficient spacing between elements
Use variables for flexibility - Define line positions as variables for easy maintenance
Test on target terminal - Verify positioning works on actual hardware
Document layouts - Keep screen layout documentation for maintenance
Validate line numbers - Ensure line numbers are within terminal limits

Common Pitfalls to Avoid

Pitfall	Problem	Solution
Hard-coded line numbers	Difficult to maintain and modify	Use variables for line positions
Overlapping text	Unreadable screen output	Plan spacing and clear areas
Invalid line numbers	Runtime errors or unexpected behavior	Validate against terminal limits
Inconsistent positioning	Poor user experience	Use standard layout templates
No error handling	Poor user feedback	Implement proper error positioning

Performance Considerations

Minimize screen updates - Only update necessary lines
Use efficient positioning - Plan layouts to minimize cursor movement
Batch screen operations - Group related displays together
Avoid excessive clearing - Clear only specific areas when needed
Use appropriate line ranges - Stay within terminal capabilities
Optimize for target hardware - Consider terminal performance limitations

Maintenance Guidelines

Use meaningful variable names - Choose descriptive names for line positions
Centralize line definitions - Define all line positions in one place
Document screen layouts - Maintain visual documentation of screen designs
Use constants for magic numbers - Define line numbers as named constants
Test across terminals - Verify layouts work on different terminal types
Plan for changes - Design layouts to accommodate future modifications

LINE Clause Quick Reference

Usage	Syntax	Example
DISPLAY positioning	AT LINE line-number	AT LINE 5 AT COLUMN 10
ACCEPT positioning	AT LINE line-number	AT LINE 8 AT COLUMN 25
SCREEN SECTION	LINE line-number	LINE 5 COLUMN 10
With variables	AT LINE variable-name	AT LINE CURRENT-LINE
With expressions	AT LINE (expression)	AT LINE (LINE-NUM + 2)

Test Your Knowledge

1. What is the primary purpose of the LINE clause in COBOL?

To define data types
To specify the vertical position on the screen
To control file operations
To perform calculations

2. In which statements can the LINE clause be used?

Only in DISPLAY statements
Only in ACCEPT statements
In both DISPLAY and ACCEPT statements
Only in SCREEN SECTION definitions

3. What is the typical range for LINE values in most COBOL implementations?

0 to 99
1 to 24 or 1 to 25
1 to 100
0 to 23

4. How do you combine LINE and COLUMN clauses for precise positioning?

LINE line-number COLUMN column-number
AT LINE line-number AT COLUMN column-number
POSITION line-number, column-number
LOCATE line-number, column-number

5. What happens if you omit the LINE clause in a DISPLAY statement?

The program will terminate with an error
The text will appear at the current cursor position
The text will appear at line 1
The text will not be displayed

COBOL Tutorial

COBOL LINE Clause - Quick Reference

Overview

Purpose and Usage

Terminal Screen Coordinates

Syntax

Basic Syntax

Valid Line Number Ranges

Using Variables and Expressions

Usage in DISPLAY Statements

Basic DISPLAY with LINE

Creating Menu Layouts

Screen Clearing and Positioning

Usage in ACCEPT Statements

Basic ACCEPT with LINE

Form Layout with ACCEPT

Dynamic Positioning with Variables

Usage in SCREEN SECTION

SCREEN SECTION with LINE

Menu Screen Definition

Using Variables in SCREEN SECTION

Practical Examples

Complete Customer Entry Program

Multi-Screen Navigation

Error Handling with LINE

Best Practices and Tips

Line Positioning Best Practices

Common Pitfalls to Avoid

Performance Considerations

Maintenance Guidelines

LINE Clause Quick Reference

Test Your Knowledge

Frequently Asked Questions

Related Concepts

COLUMN Clause

DISPLAY Statement

ACCEPT Statement

Screen Handling

SCREEN SECTION

Related Pages

COBOL Tutorial

COBOL LINE Clause - Quick Reference

Overview

Purpose and Usage

Terminal Screen Coordinates

Syntax

Basic Syntax

Valid Line Number Ranges

Using Variables and Expressions

Usage in DISPLAY Statements

Basic DISPLAY with LINE

Creating Menu Layouts

Screen Clearing and Positioning

Usage in ACCEPT Statements

Basic ACCEPT with LINE

Form Layout with ACCEPT

Dynamic Positioning with Variables

Usage in SCREEN SECTION

SCREEN SECTION with LINE

Menu Screen Definition

Using Variables in SCREEN SECTION

Practical Examples

Complete Customer Entry Program

Multi-Screen Navigation

Error Handling with LINE

Best Practices and Tips

Line Positioning Best Practices

Common Pitfalls to Avoid

Performance Considerations

Maintenance Guidelines

LINE Clause Quick Reference

Test Your Knowledge

Frequently Asked Questions

What is the difference between LINE and COLUMN clauses in COBOL screen handling?

Can you use variables or expressions with the LINE clause?

How do you clear the screen and position the cursor at the top?

What are the best practices for using LINE clauses in screen layouts?

How do you handle different terminal sizes when using LINE clauses?

Related Concepts

COLUMN Clause

DISPLAY Statement

ACCEPT Statement

Screen Handling

SCREEN SECTION

Related Pages