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COBOL Tutorial

COBOL THEN - Quick Reference

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Overview

The THEN keyword in COBOL is used in conditional statements to specify actions that should be executed when a condition evaluates to true. It is a fundamental component of decision-making and flow control in COBOL programs.

Purpose and Usage

  • Conditional execution - Execute statements when conditions are true
  • Decision making - Implement business logic based on conditions
  • Flow control - Control program execution paths
  • Data processing - Perform operations based on data values
  • Error handling - Execute error handling logic when conditions are met

THEN vs ELSE in Conditional Statements

THEN: Execute when condition is TRUE
ELSE: Execute when condition is FALSE
Result: Complete conditional logic

THEN and ELSE work together to provide complete conditional execution logic.

Syntax and Usage

THEN is used in the PROCEDURE DIVISION as part of IF-THEN conditional statements to control program flow and implement decision logic.

Basic THEN Syntax

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* Basic THEN syntax examples
       PROCEDURE DIVISION.
       
       * Simple IF-THEN statement
       IF CUSTOMER-BALANCE > 1000
           THEN
               PERFORM PREMIUM-PROCESSING
       END-IF
       
       * IF-THEN-ELSE statement
       IF CUSTOMER-STATUS = 'A'
           THEN
               PERFORM ACTIVE-CUSTOMER-PROCESSING
           ELSE
               PERFORM INACTIVE-CUSTOMER-PROCESSING
       END-IF
       
       * Multiple statements in THEN
       IF TRANSACTION-AMOUNT > 5000
           THEN
               MOVE 'HIGH-VALUE' TO TRANSACTION-TYPE
               PERFORM HIGH-VALUE-PROCESSING
               DISPLAY "High value transaction processed"
       END-IF
       
       * Nested IF-THEN statements
       IF CUSTOMER-TYPE = 'GOLD'
           THEN
               IF CUSTOMER-BALANCE > 10000
                   THEN
                       PERFORM VIP-PROCESSING
                   ELSE
                       PERFORM STANDARD-GOLD-PROCESSING
               END-IF
           ELSE
               PERFORM REGULAR-PROCESSING
       END-IF

Basic THEN usage in conditional statements for decision making.

Complete THEN Program Example

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* Complete COBOL program demonstrating THEN usage
       IDENTIFICATION DIVISION.
       PROGRAM-ID. THEN-DEMO.
       
       ENVIRONMENT DIVISION.
       CONFIGURATION SECTION.
       
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  CUSTOMER-DATA.
           05  CUSTOMER-ID     PIC 9(6).
           05  CUSTOMER-NAME   PIC X(30).
           05  CUSTOMER-BALANCE PIC 9(8)V99.
           05  CUSTOMER-STATUS PIC X.
           05  CUSTOMER-TYPE   PIC X(10).
       
       01  PROCESSING-RESULTS.
           05  PROCESSING-TYPE PIC X(20).
           05  DISCOUNT-RATE   PIC 9(3)V99.
           05  PROCESSING-STATUS PIC X(10).
       
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           PERFORM INITIALIZE-PROCESSING
           PERFORM PROCESS-CUSTOMER-DATA
           PERFORM DISPLAY-PROCESSING-RESULTS
           STOP RUN.
       
       INITIALIZE-PROCESSING.
           MOVE 123456 TO CUSTOMER-ID
           MOVE "John Smith" TO CUSTOMER-NAME
           MOVE 15000.50 TO CUSTOMER-BALANCE
           MOVE 'A' TO CUSTOMER-STATUS
           MOVE "GOLD" TO CUSTOMER-TYPE.
       
       PROCESS-CUSTOMER-DATA.
           * Process based on customer status
           IF CUSTOMER-STATUS = 'A'
               THEN
                   PERFORM PROCESS-ACTIVE-CUSTOMER
               ELSE
                   PERFORM PROCESS-INACTIVE-CUSTOMER
           END-IF.
       
       PROCESS-ACTIVE-CUSTOMER.
           * Process based on customer type
           IF CUSTOMER-TYPE = 'GOLD'
               THEN
                   IF CUSTOMER-BALANCE > 10000
                       THEN
                           MOVE 'VIP-PROCESSING' TO PROCESSING-TYPE
                           MOVE 0.15 TO DISCOUNT-RATE
                           PERFORM VIP-CUSTOMER-PROCESSING
                       ELSE
                           MOVE 'GOLD-PROCESSING' TO PROCESSING-TYPE
                           MOVE 0.10 TO DISCOUNT-RATE
                           PERFORM GOLD-CUSTOMER-PROCESSING
                   END-IF
               ELSE IF CUSTOMER-TYPE = 'SILVER'
                   THEN
                       MOVE 'SILVER-PROCESSING' TO PROCESSING-TYPE
                       MOVE 0.05 TO DISCOUNT-RATE
                       PERFORM SILVER-CUSTOMER-PROCESSING
                   ELSE
                       MOVE 'STANDARD-PROCESSING' TO PROCESSING-TYPE
                       MOVE 0.02 TO DISCOUNT-RATE
                       PERFORM STANDARD-CUSTOMER-PROCESSING
               END-IF
           END-IF.
       
       PROCESS-INACTIVE-CUSTOMER.
           MOVE 'INACTIVE-PROCESSING' TO PROCESSING-TYPE
           MOVE 0.00 TO DISCOUNT-RATE
           PERFORM INACTIVE-CUSTOMER-PROCESSING.
       
       VIP-CUSTOMER-PROCESSING.
           DISPLAY "Processing VIP customer: " CUSTOMER-NAME
           MOVE 'COMPLETED' TO PROCESSING-STATUS.
       
       GOLD-CUSTOMER-PROCESSING.
           DISPLAY "Processing Gold customer: " CUSTOMER-NAME
           MOVE 'COMPLETED' TO PROCESSING-STATUS.
       
       SILVER-CUSTOMER-PROCESSING.
           DISPLAY "Processing Silver customer: " CUSTOMER-NAME
           MOVE 'COMPLETED' TO PROCESSING-STATUS.
       
       STANDARD-CUSTOMER-PROCESSING.
           DISPLAY "Processing Standard customer: " CUSTOMER-NAME
           MOVE 'COMPLETED' TO PROCESSING-STATUS.
       
       INACTIVE-CUSTOMER-PROCESSING.
           DISPLAY "Processing Inactive customer: " CUSTOMER-NAME
           MOVE 'COMPLETED' TO PROCESSING-STATUS.
       
       DISPLAY-PROCESSING-RESULTS.
           DISPLAY "=== PROCESSING RESULTS ==="
           DISPLAY "Customer ID: " CUSTOMER-ID
           DISPLAY "Customer Name: " CUSTOMER-NAME
           DISPLAY "Processing Type: " PROCESSING-TYPE
           DISPLAY "Discount Rate: " DISCOUNT-RATE
           DISPLAY "Processing Status: " PROCESSING-STATUS.

The program demonstrates comprehensive THEN usage in decision making.

Advanced THEN Usage

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* Advanced THEN usage with complex conditional logic
       PROCEDURE DIVISION.
       
       ADVANCED-THEN-OPERATIONS.
           PERFORM COMPLEX-DECISION-MAKING
           PERFORM CONDITIONAL-DATA-PROCESSING
           PERFORM ERROR-HANDLING-LOGIC
           PERFORM BUSINESS-RULE-IMPLEMENTATION.
       
       COMPLEX-DECISION-MAKING.
           * Complex nested conditions with THEN
           IF CUSTOMER-AGE >= 18
               THEN
                   IF CUSTOMER-INCOME > 50000
                       THEN
                           IF CUSTOMER-CREDIT-SCORE > 700
                               THEN
                                   PERFORM APPROVE-LOAN
                                   MOVE 'APPROVED' TO LOAN-STATUS
                               ELSE
                                   PERFORM REVIEW-LOAN
                                   MOVE 'UNDER-REVIEW' TO LOAN-STATUS
                           END-IF
                       ELSE
                           PERFORM DENY-LOAN
                           MOVE 'DENIED' TO LOAN-STATUS
                   END-IF
               ELSE
                   PERFORM MINOR-APPLICATION-PROCESSING
                   MOVE 'MINOR' TO LOAN-STATUS
           END-IF.
       
       CONDITIONAL-DATA-PROCESSING.
           * Conditional data processing with THEN
           IF TRANSACTION-TYPE = 'DEPOSIT'
               THEN
                   IF TRANSACTION-AMOUNT > 10000
                       THEN
                           PERFORM LARGE-DEPOSIT-PROCESSING
                           MOVE 'LARGE-DEPOSIT' TO TRANSACTION-CATEGORY
                       ELSE
                           PERFORM STANDARD-DEPOSIT-PROCESSING
                           MOVE 'STANDARD-DEPOSIT' TO TRANSACTION-CATEGORY
                   END-IF
               ELSE IF TRANSACTION-TYPE = 'WITHDRAWAL'
                   THEN
                       IF TRANSACTION-AMOUNT > ACCOUNT-BALANCE
                           THEN
                               PERFORM INSUFFICIENT-FUNDS-PROCESSING
                               MOVE 'INSUFFICIENT-FUNDS' TO TRANSACTION-CATEGORY
                           ELSE
                               PERFORM STANDARD-WITHDRAWAL-PROCESSING
                               MOVE 'STANDARD-WITHDRAWAL' TO TRANSACTION-CATEGORY
                       END-IF
                   ELSE
                       PERFORM UNKNOWN-TRANSACTION-PROCESSING
                       MOVE 'UNKNOWN' TO TRANSACTION-CATEGORY
               END-IF.
       
       ERROR-HANDLING-LOGIC.
           * Error handling with THEN
           IF FILE-STATUS NOT = '00'
               THEN
                   IF FILE-STATUS = '10'
                       THEN
                           PERFORM END-OF-FILE-PROCESSING
                       ELSE IF FILE-STATUS = '23'
                           THEN
                               PERFORM FILE-NOT-FOUND-PROCESSING
                           ELSE
                               PERFORM GENERAL-ERROR-PROCESSING
                       END-IF
               ELSE
                   PERFORM NORMAL-FILE-PROCESSING
           END-IF.
       
       BUSINESS-RULE-IMPLEMENTATION.
           * Business rules with THEN
           IF ORDER-AMOUNT > 1000
               THEN
                   IF CUSTOMER-TYPE = 'PREMIUM'
                       THEN
                           MOVE 0.15 TO DISCOUNT-RATE
                           PERFORM PREMIUM-DISCOUNT-PROCESSING
                       ELSE
                           MOVE 0.10 TO DISCOUNT-RATE
                           PERFORM STANDARD-DISCOUNT-PROCESSING
                   END-IF
               ELSE
                   MOVE 0.00 TO DISCOUNT-RATE
                   PERFORM NO-DISCOUNT-PROCESSING
           END-IF.

Advanced THEN usage with complex conditional logic and decision making.

Common Use Cases

THEN is essential in various scenarios where conditional processing, decision making, and flow control are required.

Business Logic Implementation

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* Business logic implementation using THEN
       IDENTIFICATION DIVISION.
       PROGRAM-ID. BUSINESS-LOGIC-THEN.
       
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  BUSINESS-DATA.
           05  ORDER-AMOUNT    PIC 9(8)V99.
           05  CUSTOMER-TYPE   PIC X(10).
           05  PAYMENT-METHOD  PIC X(10).
           05  SHIPPING-REGION PIC X(20).
       
       01  BUSINESS-RESULTS.
           05  DISCOUNT-RATE   PIC 9(3)V99.
           05  SHIPPING-COST   PIC 9(6)V99.
           05  PROCESSING-TYPE PIC X(20).
       
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           PERFORM CALCULATE-BUSINESS-RULES
           PERFORM APPLY-BUSINESS-LOGIC
           PERFORM DISPLAY-BUSINESS-RESULTS
           STOP RUN.
       
       CALCULATE-BUSINESS-RULES.
           * Calculate discount based on order amount and customer type
           IF ORDER-AMOUNT > 1000
               THEN
                   IF CUSTOMER-TYPE = 'PREMIUM'
                       THEN
                           MOVE 0.15 TO DISCOUNT-RATE
                           MOVE 'PREMIUM-DISCOUNT' TO PROCESSING-TYPE
                       ELSE IF CUSTOMER-TYPE = 'REGULAR'
                           THEN
                               MOVE 0.10 TO DISCOUNT-RATE
                               MOVE 'REGULAR-DISCOUNT' TO PROCESSING-TYPE
                           ELSE
                               MOVE 0.05 TO DISCOUNT-RATE
                               MOVE 'STANDARD-DISCOUNT' TO PROCESSING-TYPE
                       END-IF
               ELSE
                   MOVE 0.00 TO DISCOUNT-RATE
                   MOVE 'NO-DISCOUNT' TO PROCESSING-TYPE
           END-IF.
       
       APPLY-BUSINESS-LOGIC.
           * Apply shipping costs based on region and payment method
           IF SHIPPING-REGION = 'INTERNATIONAL'
               THEN
                   IF PAYMENT-METHOD = 'CREDIT-CARD'
                       THEN
                           MOVE 50.00 TO SHIPPING-COST
                       ELSE
                           MOVE 75.00 TO SHIPPING-COST
                   END-IF
               ELSE IF SHIPPING-REGION = 'DOMESTIC'
                   THEN
                       IF ORDER-AMOUNT > 500
                           THEN
                               MOVE 0.00 TO SHIPPING-COST
                           ELSE
                               MOVE 10.00 TO SHIPPING-COST
                       END-IF
                   ELSE
                       MOVE 25.00 TO SHIPPING-COST
               END-IF.
       
       DISPLAY-BUSINESS-RESULTS.
           DISPLAY "=== BUSINESS LOGIC RESULTS ==="
           DISPLAY "Order Amount: $" ORDER-AMOUNT
           DISPLAY "Customer Type: " CUSTOMER-TYPE
           DISPLAY "Processing Type: " PROCESSING-TYPE
           DISPLAY "Discount Rate: " DISCOUNT-RATE
           DISPLAY "Shipping Cost: $" SHIPPING-COST.

Business logic implementation uses THEN for decision making and rule processing.

Data Validation and Processing

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* Data validation and processing using THEN
       IDENTIFICATION DIVISION.
       PROGRAM-ID. DATA-VALIDATION-THEN.
       
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  VALIDATION-DATA.
           05  INPUT-VALUE     PIC X(50).
           05  DATA-TYPE       PIC X(10).
           05  VALIDATION-RULE PIC X(20).
       
       01  VALIDATION-RESULTS.
           05  IS-VALID        PIC X.
           05  ERROR-MESSAGE   PIC X(100).
           05  PROCESSING-ACTION PIC X(20).
       
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           PERFORM VALIDATE-INPUT-DATA
           PERFORM PROCESS-VALIDATED-DATA
           PERFORM DISPLAY-VALIDATION-RESULTS
           STOP RUN.
       
       VALIDATE-INPUT-DATA.
           * Validate data based on type and rules
           IF DATA-TYPE = 'NUMERIC'
               THEN
                   IF INPUT-VALUE IS NUMERIC
                       THEN
                           MOVE 'Y' TO IS-VALID
                           MOVE 'PROCESS-NUMERIC' TO PROCESSING-ACTION
                       ELSE
                           MOVE 'N' TO IS-VALID
                           MOVE "Input must be numeric" TO ERROR-MESSAGE
                   END-IF
               ELSE IF DATA-TYPE = 'ALPHABETIC'
                   THEN
                       IF INPUT-VALUE IS ALPHABETIC
                           THEN
                               MOVE 'Y' TO IS-VALID
                               MOVE 'PROCESS-ALPHABETIC' TO PROCESSING-ACTION
                           ELSE
                               MOVE 'N' TO IS-VALID
                               MOVE "Input must be alphabetic" TO ERROR-MESSAGE
                       END-IF
                   ELSE IF DATA-TYPE = 'EMAIL'
                       THEN
                           IF INPUT-VALUE CONTAINS '@'
                               THEN
                                   MOVE 'Y' TO IS-VALID
                                   MOVE 'PROCESS-EMAIL' TO PROCESSING-ACTION
                               ELSE
                                   MOVE 'N' TO IS-VALID
                                   MOVE "Invalid email format" TO ERROR-MESSAGE
                           END-IF
                       ELSE
                           MOVE 'N' TO IS-VALID
                           MOVE "Unknown data type" TO ERROR-MESSAGE
                   END-IF
           END-IF.
       
       PROCESS-VALIDATED-DATA.
           * Process data based on validation results
           IF IS-VALID = 'Y'
               THEN
                   IF PROCESSING-ACTION = 'PROCESS-NUMERIC'
                       THEN
                           PERFORM NUMERIC-DATA-PROCESSING
                       ELSE IF PROCESSING-ACTION = 'PROCESS-ALPHABETIC'
                           THEN
                               PERFORM ALPHABETIC-DATA-PROCESSING
                           ELSE IF PROCESSING-ACTION = 'PROCESS-EMAIL'
                               THEN
                                   PERFORM EMAIL-DATA-PROCESSING
                           END-IF
               ELSE
                   PERFORM ERROR-HANDLING
           END-IF.
       
       NUMERIC-DATA-PROCESSING.
           DISPLAY "Processing numeric data: " INPUT-VALUE.
       
       ALPHABETIC-DATA-PROCESSING.
           DISPLAY "Processing alphabetic data: " INPUT-VALUE.
       
       EMAIL-DATA-PROCESSING.
           DISPLAY "Processing email data: " INPUT-VALUE.
       
       ERROR-HANDLING.
           DISPLAY "Error: " ERROR-MESSAGE.
       
       DISPLAY-VALIDATION-RESULTS.
           DISPLAY "=== VALIDATION RESULTS ==="
           DISPLAY "Input Value: " INPUT-VALUE
           DISPLAY "Data Type: " DATA-TYPE
           DISPLAY "Is Valid: " IS-VALID
           DISPLAY "Processing Action: " PROCESSING-ACTION.

Data validation and processing uses THEN for conditional data handling.

Error Handling and Recovery

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* Error handling and recovery using THEN
       IDENTIFICATION DIVISION.
       PROGRAM-ID. ERROR-HANDLING-THEN.
       
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  ERROR-DATA.
           05  ERROR-CODE      PIC 9(4).
           05  ERROR-TYPE      PIC X(20).
           05  ERROR-SEVERITY  PIC X(10).
       
       01  RECOVERY-ACTIONS.
           05  RECOVERY-ACTION PIC X(30).
           05  RETRY-COUNT     PIC 9(2).
           05  MAX-RETRIES     PIC 9(2) VALUE 3.
       
       PROCEDURE DIVISION.
       MAIN-LOGIC.
           PERFORM HANDLE-ERROR-SCENARIOS
           PERFORM IMPLEMENT-RECOVERY-LOGIC
           PERFORM DISPLAY-ERROR-RESULTS
           STOP RUN.
       
       HANDLE-ERROR-SCENARIOS.
           * Handle different error scenarios with THEN
           IF ERROR-CODE = 1001
               THEN
                   MOVE 'FILE-ERROR' TO ERROR-TYPE
                   IF ERROR-SEVERITY = 'CRITICAL'
                       THEN
                           PERFORM CRITICAL-FILE-ERROR-HANDLING
                       ELSE
                           PERFORM NON-CRITICAL-FILE-ERROR-HANDLING
                   END-IF
               ELSE IF ERROR-CODE = 2001
                   THEN
                       MOVE 'DATABASE-ERROR' TO ERROR-TYPE
                       IF RETRY-COUNT < MAX-RETRIES
                           THEN
                               PERFORM RETRY-DATABASE-OPERATION
                           ELSE
                               PERFORM ESCALATE-DATABASE-ERROR
                       END-IF
                   ELSE IF ERROR-CODE = 3001
                       THEN
                           MOVE 'NETWORK-ERROR' TO ERROR-TYPE
                           IF ERROR-SEVERITY = 'TEMPORARY'
                               THEN
                                   PERFORM TEMPORARY-NETWORK-ERROR-HANDLING
                               ELSE
                                   PERFORM PERMANENT-NETWORK-ERROR-HANDLING
                           END-IF
                       ELSE
                           MOVE 'UNKNOWN-ERROR' TO ERROR-TYPE
                           PERFORM UNKNOWN-ERROR-HANDLING
                   END-IF
           END-IF.
       
       IMPLEMENT-RECOVERY-LOGIC.
           * Implement recovery logic based on error type
           IF ERROR-TYPE = 'FILE-ERROR'
               THEN
                   IF ERROR-SEVERITY = 'CRITICAL'
                       THEN
                           MOVE 'RESTORE-FROM-BACKUP' TO RECOVERY-ACTION
                           PERFORM CRITICAL-RECOVERY-PROCEDURE
                       ELSE
                           MOVE 'CREATE-NEW-FILE' TO RECOVERY-ACTION
                           PERFORM NON-CRITICAL-RECOVERY-PROCEDURE
                   END-IF
               ELSE IF ERROR-TYPE = 'DATABASE-ERROR'
                   THEN
                       MOVE 'RETRY-OPERATION' TO RECOVERY-ACTION
                       PERFORM DATABASE-RECOVERY-PROCEDURE
                   ELSE IF ERROR-TYPE = 'NETWORK-ERROR'
                       THEN
                           MOVE 'SWITCH-TO-BACKUP' TO RECOVERY-ACTION
                           PERFORM NETWORK-RECOVERY-PROCEDURE
                       ELSE
                           MOVE 'LOG-AND-CONTINUE' TO RECOVERY-ACTION
                           PERFORM UNKNOWN-RECOVERY-PROCEDURE
                   END-IF
           END-IF.
       
       CRITICAL-FILE-ERROR-HANDLING.
           DISPLAY "Critical file error detected - initiating recovery".
       
       NON-CRITICAL-FILE-ERROR-HANDLING.
           DISPLAY "Non-critical file error - continuing with processing".
       
       RETRY-DATABASE-OPERATION.
           ADD 1 TO RETRY-COUNT
           DISPLAY "Retrying database operation - attempt " RETRY-COUNT.
       
       ESCALATE-DATABASE-ERROR.
           DISPLAY "Database error escalated - maximum retries exceeded".
       
       TEMPORARY-NETWORK-ERROR-HANDLING.
           DISPLAY "Temporary network error - waiting for recovery".
       
       PERMANENT-NETWORK-ERROR-HANDLING.
           DISPLAY "Permanent network error - switching to backup".
       
       UNKNOWN-ERROR-HANDLING.
           DISPLAY "Unknown error encountered - logging for analysis".
       
       DISPLAY-ERROR-RESULTS.
           DISPLAY "=== ERROR HANDLING RESULTS ==="
           DISPLAY "Error Code: " ERROR-CODE
           DISPLAY "Error Type: " ERROR-TYPE
           DISPLAY "Error Severity: " ERROR-SEVERITY
           DISPLAY "Recovery Action: " RECOVERY-ACTION
           DISPLAY "Retry Count: " RETRY-COUNT.

Error handling and recovery uses THEN for conditional error processing.

Best Practices and Tips

Following these best practices ensures effective use of THEN in COBOL applications for better readability and maintainability.

THEN Best Practices

  • Write clear, readable conditions - Use descriptive condition names and logic
  • Use meaningful variable names - Choose names that indicate the purpose of conditions
  • Structure nested statements properly - Use proper indentation for readability
  • Handle all possible conditions - Include ELSE clauses for complete logic
  • Avoid deeply nested structures - Keep nesting levels manageable for maintainability
  • Document complex logic - Add comments for complex conditional logic

Conditional Statement Patterns

PatternUsageExample
Simple IF-THENSingle condition with one actionIF condition THEN action END-IF
IF-THEN-ELSETwo-way decision makingIF condition THEN action1 ELSE action2 END-IF
Nested IF-THENComplex decision logicIF A THEN IF B THEN ACTION END-IF END-IF
Multiple ConditionsMultiple condition checkingIF condition1 AND condition2 THEN action END-IF
Conditional ProcessingConditional subroutine callsIF condition THEN PERFORM subroutine END-IF
Error HandlingConditional error processingIF error-condition THEN PERFORM error-handling END-IF

Code Structure Guidelines

  • Consistent indentation - Use consistent indentation for nested statements
  • Logical grouping - Group related conditions and actions together
  • Early returns - Use early returns to reduce nesting levels
  • Condition complexity - Break complex conditions into simpler parts
  • Action separation - Separate complex actions into subroutines
  • Error handling - Handle errors consistently throughout the program

THEN Quick Reference

AspectDescriptionExample
LocationPROCEDURE DIVISIONIn conditional statements
Basic SyntaxIF condition THEN action END-IFIF A > B THEN MOVE A TO RESULT END-IF
With ELSEIF condition THEN action1 ELSE action2 END-IFIF VALID THEN PROCESS ELSE ERROR END-IF
NestedNested IF-THEN statementsIF A THEN IF B THEN ACTION END-IF END-IF
Multiple ActionsMultiple statements in THENIF A > B THEN MOVE A TO RESULT DISPLAY "Done" END-IF

Test Your Knowledge

1. What is the primary purpose of THEN in COBOL?

  • To define arithmetic operations
  • To specify actions to execute when a condition is true in IF-THEN statements
  • To control file operations
  • To define data types

2. Where is THEN typically used in a COBOL program?

  • In the DATA DIVISION for data definitions
  • In the PROCEDURE DIVISION as part of IF-THEN conditional statements
  • In the ENVIRONMENT DIVISION for system configuration
  • In the IDENTIFICATION DIVISION

3. What types of operations can THEN handle?

  • Only file operations
  • Only database operations
  • Any COBOL statements and operations that can be executed when a condition is true
  • Only mathematical calculations

4. How does THEN differ from ELSE in IF statements?

  • They are identical in function
  • THEN executes when condition is true, ELSE executes when condition is false
  • THEN only works with numeric data
  • ELSE is more advanced than THEN

5. Which of the following is a common use of THEN?

  • File sorting operations
  • Conditional processing, decision making, and controlling program flow based on conditions
  • Database operations
  • Mathematical calculations

Frequently Asked Questions

Related Concepts

Conditional Execution

Understanding conditional execution in COBOL.

Decision Making

Working with decision making in COBOL.

Flow Control

Controlling program flow in COBOL.

Error Handling

Handling errors in COBOL programs.

Business Logic

Implementing business logic in COBOL.

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