COBOL Tutorial

COBOL SIZE Clause - Quick Reference

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Overview

The SIZE clause is used to control data item size and memory allocation in COBOL. It provides precise control over how much memory is allocated for data items, enabling optimization of memory usage and ensuring consistent storage allocation across different platforms and environments.

Purpose and Usage

Memory control - Control memory allocation for data items
Storage optimization - Optimize storage usage
Platform consistency - Ensure consistent sizes across platforms
Performance optimization - Optimize performance through proper sizing
Resource management - Manage system resources efficiently

Syntax

The SIZE clause is used in the DATA DIVISION for data size and memory allocation control.

Basic Syntax

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* Basic SIZE syntax
01 data-name PIC data-picture SIZE IS size-specification.
 
* Complete example with different size specifications
IDENTIFICATION DIVISION.
PROGRAM-ID. SIZE-EXAMPLE.
 
DATA DIVISION.
WORKING-STORAGE SECTION.
* Character data with specific size
01  SMALL-TEXT           PIC X(50) SIZE IS 50.
* Numeric data with specific size
01  SMALL-NUMBER         PIC 9(5) SIZE IS 5.
* Large character data with size control
01  LARGE-TEXT           PIC X(200) SIZE IS 200.
* Numeric data with decimal places
01  DECIMAL-NUMBER       PIC 9(7)V99 SIZE IS 9.
 
PROCEDURE DIVISION.
MAIN-LOGIC.
    * Assign values to sized data items
    MOVE "Hello World" TO SMALL-TEXT
    MOVE 12345 TO SMALL-NUMBER
    MOVE "This is a large text field with controlled size allocation" TO LARGE-TEXT
    MOVE 1234567.89 TO DECIMAL-NUMBER
    
    DISPLAY "Small text: " SMALL-TEXT
    DISPLAY "Small number: " SMALL-NUMBER
    DISPLAY "Large text: " LARGE-TEXT
    DISPLAY "Decimal number: " DECIMAL-NUMBER
    STOP RUN.

SIZE provides precise control over memory allocation and storage size for data items.

Practical Examples

Examples of using the SIZE clause in different scenarios with detailed explanations.

Database Application - Optimized Record Storage

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* Database application using SIZE for optimized record storage
DATA DIVISION.
WORKING-STORAGE SECTION.
* Customer record with controlled sizes
01  CUSTOMER-RECORD.
    05  CUSTOMER-ID       PIC 9(8) SIZE IS 8.
    05  CUSTOMER-NAME     PIC X(30) SIZE IS 30.
    05  CUSTOMER-EMAIL    PIC X(50) SIZE IS 50.
    05  CUSTOMER-PHONE    PIC X(15) SIZE IS 15.
    05  CUSTOMER-BALANCE  PIC 9(10)V99 SIZE IS 12.
    05  CUSTOMER-STATUS   PIC X(1) SIZE IS 1.
 
* Product record with memory optimization
01  PRODUCT-RECORD.
    05  PRODUCT-CODE      PIC X(10) SIZE IS 10.
    05  PRODUCT-NAME      PIC X(40) SIZE IS 40.
    05  PRODUCT-PRICE     PIC 9(7)V99 SIZE IS 9.
    05  PRODUCT-QUANTITY  PIC 9(5) SIZE IS 5.
    05  PRODUCT-CATEGORY  PIC X(20) SIZE IS 20.
 
PROCEDURE DIVISION.
PROCESS-CUSTOMER-DATA.
    * Initialize customer record with controlled sizes
    MOVE 12345678 TO CUSTOMER-ID
    MOVE "John Doe" TO CUSTOMER-NAME
    MOVE "john.doe@email.com" TO CUSTOMER-EMAIL
    MOVE "(555) 123-4567" TO CUSTOMER-PHONE
    MOVE 1500.75 TO CUSTOMER-BALANCE
    MOVE "A" TO CUSTOMER-STATUS
    
    DISPLAY "Customer ID: " CUSTOMER-ID
    DISPLAY "Customer Name: " CUSTOMER-NAME
    DISPLAY "Customer Email: " CUSTOMER-EMAIL
    DISPLAY "Customer Phone: " CUSTOMER-PHONE
    DISPLAY "Customer Balance: " CUSTOMER-BALANCE
    DISPLAY "Customer Status: " CUSTOMER-STATUS
    
    * Initialize product record
    MOVE "PROD001" TO PRODUCT-CODE
    MOVE "Laptop Computer" TO PRODUCT-NAME
    MOVE 999.99 TO PRODUCT-PRICE
    MOVE 100 TO PRODUCT-QUANTITY
    MOVE "Electronics" TO PRODUCT-CATEGORY
    
    DISPLAY "Product Code: " PRODUCT-CODE
    DISPLAY "Product Name: " PRODUCT-NAME
    DISPLAY "Product Price: " PRODUCT-PRICE
    DISPLAY "Product Quantity: " PRODUCT-QUANTITY
    DISPLAY "Product Category: " PRODUCT-CATEGORY.

This example demonstrates how SIZE optimizes memory usage in database applications by controlling the exact storage size for each field in customer and product records. Each field has a precisely defined size that matches its expected data requirements, preventing memory waste while ensuring sufficient space for the data.

Embedded System - Memory-Constrained Environment

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* Embedded system using SIZE for memory-constrained environment
DATA DIVISION.
WORKING-STORAGE SECTION.
* Sensor data with minimal memory usage
01  SENSOR-DATA.
    05  TEMPERATURE       PIC S9(3) SIZE IS 3.
    05  HUMIDITY          PIC 9(3) SIZE IS 3.
    05  PRESSURE          PIC 9(4) SIZE IS 4.
    05  STATUS-FLAG       PIC X(1) SIZE IS 1.
    05  ERROR-CODE        PIC 9(2) SIZE IS 2.
 
* Communication buffer with controlled size
01  COMM-BUFFER.
    05  MESSAGE-ID        PIC X(8) SIZE IS 8.
    05  MESSAGE-TYPE      PIC X(4) SIZE IS 4.
    05  MESSAGE-DATA      PIC X(32) SIZE IS 32.
    05  CHECKSUM          PIC X(2) SIZE IS 2.
 
* System configuration with optimized storage
01  SYSTEM-CONFIG.
    05  DEVICE-ID         PIC X(6) SIZE IS 6.
    05  VERSION-NUM       PIC 9(2)V9(2) SIZE IS 4.
    05  OPERATION-MODE    PIC X(1) SIZE IS 1.
    05  TIMEOUT-VALUE     PIC 9(3) SIZE IS 3.
 
PROCEDURE DIVISION.
MANAGE-EMBEDDED-SYSTEM.
    * Initialize sensor data with minimal memory usage
    MOVE 25 TO TEMPERATURE
    MOVE 60 TO HUMIDITY
    MOVE 1013 TO PRESSURE
    MOVE "N" TO STATUS-FLAG
    MOVE 0 TO ERROR-CODE
    
    DISPLAY "Temperature: " TEMPERATURE "°C"
    DISPLAY "Humidity: " HUMIDITY "%"
    DISPLAY "Pressure: " PRESSURE " hPa"
    DISPLAY "Status: " STATUS-FLAG
    DISPLAY "Error Code: " ERROR-CODE
    
    * Initialize communication buffer
    MOVE "MSG001" TO MESSAGE-ID
    MOVE "DATA" TO MESSAGE-TYPE
    MOVE "Sensor reading data packet" TO MESSAGE-DATA
    MOVE "AB" TO CHECKSUM
    
    DISPLAY "Message ID: " MESSAGE-ID
    DISPLAY "Message Type: " MESSAGE-TYPE
    DISPLAY "Message Data: " MESSAGE-DATA
    DISPLAY "Checksum: " CHECKSUM
    
    * Initialize system configuration
    MOVE "DEV001" TO DEVICE-ID
    MOVE 1.25 TO VERSION-NUM
    MOVE "N" TO OPERATION-MODE
    MOVE 300 TO TIMEOUT-VALUE
    
    DISPLAY "Device ID: " DEVICE-ID
    DISPLAY "Version: " VERSION-NUM
    DISPLAY "Operation Mode: " OPERATION-MODE
    DISPLAY "Timeout: " TIMEOUT-VALUE " seconds".

This example shows how SIZE optimizes memory usage in embedded systems where memory is severely constrained. Each data structure (sensor data, communication buffer, system configuration) uses precisely sized fields that minimize memory consumption while providing sufficient space for the required data. This is crucial for embedded systems where every byte of memory counts.

Financial Application - Precise Amount Storage

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* Financial application using SIZE for precise amount storage
DATA DIVISION.
WORKING-STORAGE SECTION.
* Transaction record with controlled sizes
01  TRANSACTION-RECORD.
    05  TRANSACTION-ID    PIC 9(12) SIZE IS 12.
    05  ACCOUNT-NUMBER    PIC 9(10) SIZE IS 10.
    05  TRANSACTION-TYPE  PIC X(4) SIZE IS 4.
    05  TRANSACTION-AMOUNT PIC 9(10)V99 SIZE IS 12.
    05  TRANSACTION-DATE  PIC 9(8) SIZE IS 8.
    05  TRANSACTION-TIME  PIC 9(6) SIZE IS 6.
    05  STATUS-CODE       PIC X(2) SIZE IS 2.
 
* Currency conversion with precise sizing
01  CURRENCY-CONVERSION.
    05  SOURCE-CURRENCY   PIC X(3) SIZE IS 3.
    05  TARGET-CURRENCY   PIC X(3) SIZE IS 3.
    05  EXCHANGE-RATE     PIC 9(6)V6 SIZE IS 12.
    05  CONVERSION-AMOUNT PIC 9(10)V99 SIZE IS 12.
    05  CONVERSION-FEE    PIC 9(5)V99 SIZE IS 7.
 
* Account summary with optimized storage
01  ACCOUNT-SUMMARY.
    05  ACCOUNT-ID        PIC 9(10) SIZE IS 10.
    05  CURRENT-BALANCE   PIC S9(12)V99 SIZE IS 14.
    05  AVAILABLE-BALANCE PIC S9(12)V99 SIZE IS 14.
    05  HOLD-AMOUNT       PIC 9(10)V99 SIZE IS 12.
    05  LAST-TRANSACTION  PIC 9(8) SIZE IS 8.
 
PROCEDURE DIVISION.
PROCESS-FINANCIAL-TRANSACTIONS.
    * Initialize transaction record
    MOVE 123456789012 TO TRANSACTION-ID
    MOVE 9876543210 TO ACCOUNT-NUMBER
    MOVE "DEBT" TO TRANSACTION-TYPE
    MOVE 1500.75 TO TRANSACTION-AMOUNT
    MOVE 20231215 TO TRANSACTION-DATE
    MOVE 143022 TO TRANSACTION-TIME
    MOVE "OK" TO STATUS-CODE
    
    DISPLAY "Transaction ID: " TRANSACTION-ID
    DISPLAY "Account Number: " ACCOUNT-NUMBER
    DISPLAY "Transaction Type: " TRANSACTION-TYPE
    DISPLAY "Amount: " TRANSACTION-AMOUNT
    DISPLAY "Date: " TRANSACTION-DATE
    DISPLAY "Time: " TRANSACTION-TIME
    DISPLAY "Status: " STATUS-CODE
    
    * Initialize currency conversion
    MOVE "USD" TO SOURCE-CURRENCY
    MOVE "EUR" TO TARGET-CURRENCY
    MOVE 0.850000 TO EXCHANGE-RATE
    MOVE 1000.00 TO CONVERSION-AMOUNT
    MOVE 5.50 TO CONVERSION-FEE
    
    DISPLAY "Source Currency: " SOURCE-CURRENCY
    DISPLAY "Target Currency: " TARGET-CURRENCY
    DISPLAY "Exchange Rate: " EXCHANGE-RATE
    DISPLAY "Conversion Amount: " CONVERSION-AMOUNT
    DISPLAY "Conversion Fee: " CONVERSION-FEE
    
    * Initialize account summary
    MOVE 1234567890 TO ACCOUNT-ID
    MOVE 50000.00 TO CURRENT-BALANCE
    MOVE 45000.00 TO AVAILABLE-BALANCE
    MOVE 5000.00 TO HOLD-AMOUNT
    MOVE 20231215 TO LAST-TRANSACTION
    
    DISPLAY "Account ID: " ACCOUNT-ID
    DISPLAY "Current Balance: " CURRENT-BALANCE
    DISPLAY "Available Balance: " AVAILABLE-BALANCE
    DISPLAY "Hold Amount: " HOLD-AMOUNT
    DISPLAY "Last Transaction: " LAST-TRANSACTION.

This example demonstrates how SIZE ensures precise storage for financial data where accuracy and consistency are critical. Each field in transaction records, currency conversions, and account summaries has a precisely defined size that accommodates the expected data range while preventing memory waste. This is especially important in financial applications where data integrity and storage efficiency are paramount.

Best Practices

Understanding best practices ensures effective use of the SIZE clause.

Best Practices

Choose appropriate sizes - Select sizes based on expected data requirements
Consider memory constraints - Balance size with memory availability
Validate data fits - Ensure data fits within specified sizes
Document size requirements - Document why specific sizes were chosen
Test boundary conditions - Test with maximum expected data sizes

Test Your Knowledge

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

To resize files
To control data item size and memory allocation
To resize programs
To resize memory

2. In which COBOL division is the SIZE clause typically used?

IDENTIFICATION DIVISION
ENVIRONMENT DIVISION
DATA DIVISION
PROCEDURE DIVISION

3. What does the SIZE clause control in data definition?

Data validation
Memory allocation and storage size
Data type
Data format

4. Can SIZE be used with all data types?

Yes, with all data types
No, only with numeric types
No, only with character types
Only with specific data types

5. What is the relationship between SIZE and memory usage?

They are unrelated
SIZE directly controls memory allocation
SIZE only affects display
SIZE is for validation only

COBOL Tutorial

COBOL SIZE Clause - Quick Reference

Overview

Purpose and Usage

Syntax

Basic Syntax

Practical Examples

Database Application - Optimized Record Storage

Embedded System - Memory-Constrained Environment

Financial Application - Precise Amount Storage

Best Practices

Best Practices

Test Your Knowledge

Frequently Asked Questions

Related Concepts

Data Types

Memory Management

Performance Optimization

Related Pages

COBOL Tutorial

COBOL SIZE Clause - Quick Reference

Overview

Purpose and Usage

Syntax

Basic Syntax

Practical Examples

Database Application - Optimized Record Storage

Embedded System - Memory-Constrained Environment

Financial Application - Precise Amount Storage

Best Practices

Best Practices

Test Your Knowledge

Frequently Asked Questions

What is the difference between SIZE and other data definition clauses?

How do you implement the SIZE clause in a COBOL program?

What are some common use cases for the SIZE clause?

How does the SIZE clause affect program performance and memory usage?

Related Concepts

Data Types

Memory Management

Performance Optimization

Related Pages