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COBOL Tutorial

COBOL CYCLE Statement

The CYCLE statement in COBOL is used within the Report Writer feature to manually force control breaks in report processing, allowing precise control over when control footings and headings are generated.

Syntax

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CYCLE control-identifier

Where control-identifier is the name of a control field defined in the CONTROL clause of the RD entry.

Basic Report Control Example

The CYCLE statement is primarily used in report processing to create manual control breaks:

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REPORT SECTION.
RD SALES-REPORT
    CONTROL IS FINAL, REGION-CODE, SALESMAN-ID.
 
01 DETAIL-LINE TYPE IS DETAIL.
   05 COLUMN 10    PIC X(20) SOURCE CUSTOMER-NAME.
   05 COLUMN 35    PIC ZZ,ZZ9.99 SOURCE SALE-AMOUNT.
 
01 REGION-FOOTING TYPE IS CONTROL FOOTING REGION-CODE.
   05 COLUMN 25    PIC X(15) VALUE "REGION TOTAL:".
   05 COLUMN 42    PIC ZZ,ZZ9.99 SUM SALE-AMOUNT.
 
PROCEDURE DIVISION.
PROCESS-SALES.
    *> Force a control break for region
    CYCLE REGION-CODE.
    
    *> Generate detail line
    GENERATE DETAIL-LINE.

Practical Implementation

Regional Sales Report with Manual Breaks

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DATA DIVISION.
FILE SECTION.
FD SALES-FILE.
01 SALES-RECORD.
   05 REGION-CODE          PIC X(3).
   05 SALESMAN-ID          PIC X(5).
   05 CUSTOMER-NAME        PIC X(30).
   05 SALE-AMOUNT          PIC 9(7)V99.
 
WORKING-STORAGE SECTION.
01 WS-RECORD-COUNT       PIC 9(5) VALUE ZERO.
01 WS-PAGE-BREAK-COUNT   PIC 9(3) VALUE 20.
 
REPORT SECTION.
RD REGIONAL-SALES-REPORT
    CONTROL IS FINAL, REGION-CODE.
 
01 REPORT-HEADING TYPE IS REPORT HEADING.
   05 LINE 1 COLUMN 25 PIC X(30) VALUE "REGIONAL SALES ANALYSIS".
 
01 DETAIL-LINE TYPE IS DETAIL.
   05 LINE PLUS 1.
   05 COLUMN 1     PIC X(3)      SOURCE REGION-CODE.
   05 COLUMN 15    PIC X(20)     SOURCE CUSTOMER-NAME.
   05 COLUMN 40    PIC ZZ,ZZ9.99 SOURCE SALE-AMOUNT.
 
01 REGION-FOOTING TYPE IS CONTROL FOOTING REGION-CODE.
   05 LINE PLUS 2.
   05 COLUMN 25    PIC X(20) VALUE "REGION TOTAL:".
   05 COLUMN 50    PIC ZZ,ZZ9.99 SUM SALE-AMOUNT.
 
PROCEDURE DIVISION.
MAIN-PROCESSING.
    OPEN INPUT SALES-FILE
    OPEN OUTPUT REPORT-FILE
    INITIATE REGIONAL-SALES-REPORT
    
    PERFORM PROCESS-SALES-RECORDS
    
    TERMINATE REGIONAL-SALES-REPORT
    CLOSE SALES-FILE REPORT-FILE
    STOP RUN.
 
PROCESS-SALES-RECORDS.
    READ SALES-FILE
        AT END MOVE 'Y' TO EOF-FLAG
    END-READ
    
    PERFORM UNTIL EOF-FLAG = 'Y'
        ADD 1 TO WS-RECORD-COUNT
        
        *> Force page break every 20 records
        IF FUNCTION MOD(WS-RECORD-COUNT, WS-PAGE-BREAK-COUNT) = 0
            CYCLE REGION-CODE
        END-IF
        
        GENERATE DETAIL-LINE
        
        READ SALES-FILE
            AT END MOVE 'Y' TO EOF-FLAG
        END-READ
    END-PERFORM.

This example shows how CYCLE forces region subtotals every 20 records, creating regular page breaks for better report readability.

Financial Report with Period-End Processing

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DATA DIVISION.
WORKING-STORAGE SECTION.
01 WS-PERIOD-END-DATE    PIC 9(8).
01 WS-TRANSACTION-COUNT  PIC 9(7) VALUE ZERO.
 
REPORT SECTION.
RD FINANCIAL-REPORT
    CONTROL IS FINAL, ACCOUNT-NUMBER.
 
01 TRANSACTION-DETAIL TYPE IS DETAIL.
   05 LINE PLUS 1.
   05 COLUMN 1     PIC 9(8)        SOURCE ACCOUNT-NUMBER.
   05 COLUMN 12    PIC 99/99/9999  SOURCE TRANSACTION-DATE.
   05 COLUMN 25    PIC X(2)        SOURCE TRANSACTION-TYPE.
   05 COLUMN 30    PIC -(9)9,999.99 SOURCE AMOUNT.
 
01 ACCOUNT-FOOTING TYPE IS CONTROL FOOTING ACCOUNT-NUMBER.
   05 LINE PLUS 2.
   05 COLUMN 20    PIC X(20) VALUE "ACCOUNT BALANCE:".
   05 COLUMN 45    PIC -(9)9,999.99 SUM AMOUNT.
 
PROCEDURE DIVISION.
PROCESS-TRANSACTIONS.
    PERFORM UNTIL EOF-FLAG = 'Y'
        ADD 1 TO WS-TRANSACTION-COUNT
        
        *> Check for period-end date boundary
        IF TRANSACTION-DATE > WS-PERIOD-END-DATE
            CYCLE ACCOUNT-NUMBER
            MOVE TRANSACTION-DATE TO WS-PERIOD-END-DATE
        END-IF
        
        *> Force account summary every 50 transactions
        IF FUNCTION MOD(WS-TRANSACTION-COUNT, 50) = 0
            CYCLE ACCOUNT-NUMBER
        END-IF
        
        GENERATE TRANSACTION-DETAIL
        
        READ TRANSACTION-FILE
            AT END MOVE 'Y' TO EOF-FLAG
        END-READ
    END-PERFORM.

This example demonstrates CYCLE usage for both time-based (period-end) and volume-based (every 50 transactions) control breaks.

Advanced CYCLE Techniques

Hierarchical Control Levels

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REPORT SECTION.
RD HIERARCHICAL-REPORT
    CONTROL IS FINAL, DIVISION-CODE, DEPARTMENT-CODE, EMPLOYEE-ID.
 
*> When CYCLE DIVISION-CODE is executed:
*> 1. EMPLOYEE-ID footings are generated
*> 2. DEPARTMENT-CODE footings are generated  
*> 3. DIVISION-CODE footings are generated
*> 4. New DIVISION-CODE headings are generated
*> 5. New DEPARTMENT-CODE headings are generated
*> 6. New EMPLOYEE-ID headings are generated
 
PROCEDURE DIVISION.
PROCESS-HIERARCHY.
    *> This will cycle all levels from DIVISION down
    CYCLE DIVISION-CODE.
    
    *> This will cycle only DEPARTMENT and EMPLOYEE levels
    CYCLE DEPARTMENT-CODE.
    
    *> This will cycle only EMPLOYEE level
    CYCLE EMPLOYEE-ID.

CYCLE affects all control levels from the specified level down to the detail level, maintaining proper hierarchical report structure.

Conditional CYCLE Processing

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WORKING-STORAGE SECTION.
01 WS-BUSINESS-RULES.
   05 WS-MIN-GROUP-SIZE      PIC 9(3) VALUE 5.
   05 WS-CURRENT-GROUP-SIZE  PIC 9(3) VALUE ZERO.
   05 WS-THRESHOLD-AMOUNT    PIC 9(7)V99 VALUE 10000.00.
   05 WS-PAGE-LINE-COUNT     PIC 9(3) VALUE ZERO.
   05 WS-MAX-LINES-PER-PAGE  PIC 9(3) VALUE 55.
 
PROCEDURE DIVISION.
CONDITIONAL-CYCLE-PROCESSING.
    PERFORM UNTIL EOF-FLAG = 'Y'
        *> Check page overflow condition
        IF WS-PAGE-LINE-COUNT > WS-MAX-LINES-PER-PAGE
            CYCLE DEPARTMENT-CODE
            MOVE ZERO TO WS-PAGE-LINE-COUNT
        END-IF
        
        *> Check business rule for minimum group size
        IF WS-CURRENT-GROUP-SIZE >= WS-MIN-GROUP-SIZE
           AND SALE-AMOUNT > WS-THRESHOLD-AMOUNT
            CYCLE SALESMAN-ID
            MOVE ZERO TO WS-CURRENT-GROUP-SIZE
        END-IF
        
        GENERATE DETAIL-LINE
        ADD 1 TO WS-CURRENT-GROUP-SIZE
        ADD 1 TO WS-PAGE-LINE-COUNT
        
        READ SALES-FILE
            AT END MOVE 'Y' TO EOF-FLAG
        END-READ
    END-PERFORM.

This shows CYCLE with complex business logic including page overflow management, minimum group sizes, and threshold-based processing.

Best Practices and Performance

Performance Guidelines

  • Use CYCLE sparingly to avoid excessive processing overhead
  • Implement cycle counting to prevent infinite loops
  • Consider the impact on report readability and user experience
  • Test CYCLE logic thoroughly with various data scenarios
  • Document CYCLE usage for maintenance purposes

Error Handling Example

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WORKING-STORAGE SECTION.
01 WS-CYCLE-CONTROL.
   05 WS-CYCLE-COUNT         PIC 9(5) VALUE ZERO.
   05 WS-MAX-CYCLES          PIC 9(5) VALUE 1000.
   05 WS-CYCLE-ERROR-FLAG    PIC X VALUE 'N'.
 
PROCEDURE DIVISION.
SAFE-CYCLE-PROCESSING.
    *> Validate before cycling
    IF WS-CYCLE-COUNT < WS-MAX-CYCLES
        ADD 1 TO WS-CYCLE-COUNT
        CYCLE DEPARTMENT-CODE
    ELSE
        MOVE 'Y' TO WS-CYCLE-ERROR-FLAG
        DISPLAY "ERROR: Maximum cycles exceeded"
        PERFORM ERROR-RECOVERY
    END-IF.
 
ERROR-RECOVERY.
    DISPLAY "CYCLE limit reached at record: " WS-RECORD-COUNT.
    TERMINATE CURRENT-REPORT.
    MOVE 8 TO RETURN-CODE.

Related Topics

  • Report Writer Feature
  • Control Break Processing
  • GENERATE Statement
  • INITIATE and TERMINATE Statements

Frequently Asked Questions

What is the primary purpose of the CYCLE statement?

The CYCLE statement manually forces control breaks in report processing, triggering the generation of control footings and headings at specific points, independent of actual data changes.

How does CYCLE affect multiple control levels?

When CYCLE is executed for a specific control level, it affects all control levels from that level down to the detail level, generating footings from lowest to highest, then headings from highest to lowest.

Can CYCLE be used outside Report Writer?

No, CYCLE is specifically designed for COBOL's Report Writer feature and requires a properly defined Report Section with control hierarchies.