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COBOL Tutorial

COBOL INITIALIZED - Quick Reference

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Overview

The INITIALIZED clause in COBOL is used to set initial values for data fields when they are first created. It ensures that fields start with known, predictable values rather than containing random data from memory.

Purpose and Usage

  • Set initial values for data fields
  • Ensure predictable starting state for variables
  • Prevent undefined data from causing bugs
  • Initialize complex structures (groups, arrays)

Syntax

The INITIALIZED clause can be used with various data types and structures:

Basic Syntax

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01  field-name PIC X(10) INITIALIZED.
01  group-name INITIALIZED.
01  array-name OCCURS 5 TIMES PIC 9(3) INITIALIZED.

INITIALIZED sets appropriate default values based on the data type.

Example: Group Initialization

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01  EMPLOYEE-RECORD INITIALIZED.
    05  EMP-ID        PIC 9(5).
    05  EMP-NAME      PIC X(30).
    05  EMP-SALARY    PIC 9(7)V99.

All fields in the group are initialized with appropriate default values.

Example: Array Initialization

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01  SCORES-TABLE.
    05  SCORE OCCURS 10 TIMES PIC 9(3) INITIALIZED.

All 10 elements of the array are initialized to zero.

Practical Examples

Here are some practical uses of the INITIALIZED clause in COBOL programs:

Initializing Counters and Totals

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01  WORKING-VARIABLES.
    05  RECORD-COUNT    PIC 9(6) INITIALIZED.
    05  TOTAL-AMOUNT    PIC 9(10)V99 INITIALIZED.
    05  ERROR-COUNT     PIC 9(3) INITIALIZED.

Ensures counters start at zero for accurate calculations.

Initializing String Fields

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01  MESSAGE-FIELDS.
    05  STATUS-MESSAGE  PIC X(50) INITIALIZED.
    05  ERROR-MESSAGE   PIC X(100) INITIALIZED.
    05  USER-INPUT      PIC X(20) INITIALIZED.

String fields are initialized with spaces.

Complex Structure Initialization

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01  CUSTOMER-DATA INITIALIZED.
    05  CUST-ID        PIC 9(8).
    05  CUST-NAME      PIC X(40).
    05  CUST-ADDRESS.
        10  STREET      PIC X(30).
        10  CITY        PIC X(20).
        10  STATE       PIC X(2).
        10  ZIP         PIC 9(5).
    05  CUST-BALANCE   PIC 9(8)V99.

Entire customer record structure is initialized with appropriate defaults.

Best Practices

  • Use INITIALIZED for all fields that need predictable starting values.
  • Initialize counters and totals to ensure accurate calculations.
  • Use INITIALIZED for complex data structures to ensure all fields are properly set.
  • Consider using INITIALIZED for arrays to ensure all elements start with known values.
  • Document any special initialization requirements in your code comments.

Common Pitfalls

  • Forgetting to initialize fields that are used in calculations.
  • Assuming fields will have specific default values without INITIALIZED.
  • Not initializing arrays, which can lead to unpredictable behavior.
  • Overlooking the need to initialize complex nested structures.

Test Your Knowledge

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

  • To initialize a program
  • To set initial values for data fields
  • To start a file
  • To begin a section

2. Where is the INITIALIZED clause typically used?

  • In the PROCEDURE DIVISION
  • In the DATA DIVISION
  • In the ENVIRONMENT DIVISION
  • In the IDENTIFICATION DIVISION

3. What happens if you don't use INITIALIZED on a field?

  • The field gets a default value
  • The field contains undefined data
  • The field is set to zero
  • The field is set to spaces

4. Can INITIALIZED be used with all data types?

  • Yes, always
  • No, only with numeric fields
  • No, only with alphanumeric fields
  • It depends on the COBOL compiler

5. What is the difference between INITIALIZED and VALUE?

  • They are the same
  • INITIALIZED is for groups, VALUE is for elementary items
  • VALUE is obsolete, INITIALIZED is modern
  • INITIALIZED is for arrays, VALUE is for single fields

Frequently Asked Questions

Related Concepts

VALUE Clause

Setting specific values for data fields.

DATA DIVISION

Defining data structures in COBOL.

OCCURS Clause

Working with arrays in COBOL.

PIC Clause

Defining data types and formats.

WORKING-STORAGE SECTION

Managing program variables.

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