COBOL Tutorial

COBOL Verbs Overview

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Introduction to COBOL Verbs

COBOL verbs are the action words that perform operations in a COBOL program. They form the core of the PROCEDURE DIVISION, where they execute the actual instructions that manipulate data, control program flow, and interact with external resources.

COBOL verbs can be categorized into several groups based on their function. Understanding these categories helps organize code and clarify the purpose of different operations in your program.

Basic Verb Structure

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verb-name operand1, operand2 ... [optional-phrases]

COBOL verbs typically appear at the beginning of a statement, followed by their operands and optional phrases.

Computational Verbs

Computational verbs perform arithmetic operations on numeric data. These verbs are fundamental for business applications that need to calculate totals, percentages, averages, and other numerical values.

ADD

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ADD A, B, C TO TOTAL.
ADD A, B GIVING SUM.
ADD A TO B ROUNDED.
ADD A TO B ON SIZE ERROR DISPLAY "Overflow".

Adds two or more numeric values.

SUBTRACT

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SUBTRACT A FROM B.
SUBTRACT A, B FROM C.
SUBTRACT A, B FROM C GIVING RESULT.
SUBTRACT A FROM B ROUNDED.

Subtracts one or more numeric values from another.

MULTIPLY

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MULTIPLY A BY B.
MULTIPLY A BY B GIVING PRODUCT.
MULTIPLY A BY B ROUNDED.
MULTIPLY A BY B ON SIZE ERROR PERFORM ERROR-ROUTINE.

Multiplies two numeric values.

DIVIDE

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DIVIDE A INTO B.
DIVIDE A INTO B GIVING QUOTIENT.
DIVIDE A INTO B GIVING QUOTIENT REMAINDER REMAINDER-FIELD.
DIVIDE A BY B GIVING QUOTIENT.

Divides one numeric value by another.

COMPUTE

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COMPUTE RESULT = A + B * C.
COMPUTE AREA = 3.14159 * RADIUS ** 2.
COMPUTE DISCOUNT ROUNDED = PRICE * 0.25.
COMPUTE TOTAL = SUBTOTAL + (SUBTOTAL * TAX-RATE) ON SIZE ERROR PERFORM OVERFLOW-ROUTINE.

Evaluates arithmetic expressions using multiple operations and assigns the result to a variable.

Common Features of Computational Verbs

ROUNDED option - Rounds the result to the precision defined in the PICTURE clause
ON SIZE ERROR phrase - Executed when the result cannot fit in the receiving field
NOT ON SIZE ERROR phrase - Executed when no size error occurs
GIVING option - Specifies where to store the result (doesn't modify the operands)

Example: Using Multiple Computational Verbs

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COMPUTE GROSS-PAY = HOURS-WORKED * HOURLY-RATE.
    
IF HOURS-WORKED > 40
    MULTIPLY HOURLY-RATE BY 1.5 GIVING OVERTIME-RATE
    SUBTRACT 40 FROM HOURS-WORKED GIVING OVERTIME-HOURS
    MULTIPLY OVERTIME-HOURS BY OVERTIME-RATE GIVING OVERTIME-PAY
    ADD OVERTIME-PAY TO GROSS-PAY
END-IF.
 
COMPUTE NET-PAY ROUNDED = GROSS-PAY * (1 - TAX-RATE).
 
IF NET-PAY > 0
    MULTIPLY PRIOR-BALANCE BY -1 GIVING NEGATIVE-BALANCE
    ADD NET-PAY TO NEGATIVE-BALANCE
    IF NEGATIVE-BALANCE > 0
        MOVE NEGATIVE-BALANCE TO NET-PAY
        MOVE 0 TO PRIOR-BALANCE
    ELSE
        ADD NEGATIVE-BALANCE TO PRIOR-BALANCE
        MOVE 0 TO NET-PAY
    END-IF
END-IF.

This example shows how different computational verbs work together to calculate an employee's paycheck.

Data Movement Verbs

Data movement verbs transfer data between memory locations, initialize fields, and manipulate strings. These operations are essential for data preparation, formatting, and transformation.

MOVE

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MOVE "JOHN" TO CUSTOMER-NAME.
MOVE SPACES TO OUTPUT-FIELD.
MOVE ZEROS TO COUNTER.
MOVE "123" TO NUMERIC-FIELD.
MOVE CUSTOMER-RECORD TO OUTPUT-RECORD.
MOVE CORRESPONDING INPUT-REC TO OUTPUT-REC.

Copies data from one field to another. One of the most commonly used COBOL verbs.

INITIALIZE

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INITIALIZE CUSTOMER-RECORD.
INITIALIZE OUTPUT-AREA REPLACING
   NUMERIC DATA BY ZEROS
   ALPHANUMERIC DATA BY SPACES.
INITIALIZE WS-TABLE-AREA REPLACING
   NUMERIC DATA BY 1.

Sets fields to their default values or specified values. More powerful than MOVE for complex structures.

STRING

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STRING "First" DELIMITED BY SIZE
       " " DELIMITED BY SIZE
       "Last" DELIMITED BY SIZE
       INTO FULL-NAME
       WITH POINTER NAME-PTR
       ON OVERFLOW PERFORM ERROR-ROUTINE
END-STRING.

Concatenates strings with powerful formatting options.

UNSTRING

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UNSTRING FULL-NAME
       DELIMITED BY ALL SPACES
       INTO FIRST-NAME
            LAST-NAME
       TALLYING IN WORD-COUNT
       ON OVERFLOW PERFORM ERROR-ROUTINE
END-UNSTRING.

Splits strings into multiple fields based on delimiters.

INSPECT

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INSPECT FIELD-1 TALLYING COUNT-1 FOR ALL "A".
INSPECT FIELD-2 REPLACING ALL "a" BY "A".
INSPECT FIELD-3 CONVERTING "abcdef" TO "ABCDEF".
INSPECT FIELD-4 TALLYING COUNT-2 FOR CHARACTERS
              BEFORE INITIAL "Z".

Counts, replaces, or converts characters in strings.

SET

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SET INDEX-1 TO 1.
SET INDEX-1 UP BY 2.
SET ADDRESS OF WS-POINTER TO ADDRESS OF WS-DATA.
SET BONUS-SWITCH TO TRUE.
SET TABLE-INDEX TO 5.

Assigns values to special items like indexes, pointers, and condition names.

MOVE CORRESPONDING

A special form of MOVE that copies fields with matching names between group items:

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01 INPUT-RECORD.
   05 CUSTOMER-ID    PIC X(6).
   05 CUSTOMER-NAME  PIC X(30).
   05 BALANCE        PIC 9(7)V99.
   05 OTHER-DATA     PIC X(20).
 
01 OUTPUT-RECORD.
   05 CUSTOMER-ID    PIC X(6).
   05 CUSTOMER-NAME  PIC X(30).
   05 TAX-ID         PIC X(9).
   05 BALANCE        PIC 9(7)V99.
 
MOVE CORRESPONDING INPUT-RECORD TO OUTPUT-RECORD.
*> Only CUSTOMER-ID, CUSTOMER-NAME, and BALANCE are copied

Example: Complex String Processing

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*> Input field contains "JOHN DOE,123 MAIN ST,ANYTOWN,TX,12345"
 
*> Initialize work fields
MOVE SPACES TO FIRST-NAME
             LAST-NAME
             STREET-ADDRESS
             CITY
             STATE
             ZIP-CODE.
MOVE 1 TO PTR.
 
*> Extract name
UNSTRING INPUT-FIELD DELIMITED BY ","
         INTO FULL-NAME
         WITH POINTER PTR
END-UNSTRING.
 
*> Split name into first and last
UNSTRING FULL-NAME DELIMITED BY ALL SPACES
         INTO FIRST-NAME
              LAST-NAME
END-UNSTRING.
 
*> Convert name to proper case
INSPECT FIRST-NAME REPLACING ALL "JOHN" BY "John".
INSPECT LAST-NAME REPLACING ALL "DOE" BY "Doe".
 
*> Extract address
UNSTRING INPUT-FIELD DELIMITED BY ","
         INTO WS-TEMP
              STREET-ADDRESS
              CITY
              STATE
              ZIP-CODE
         WITH POINTER PTR
END-UNSTRING.
 
*> Build formatted output
STRING "Customer: " DELIMITED BY SIZE
       FIRST-NAME DELIMITED BY SPACE
       " " DELIMITED BY SIZE
       LAST-NAME DELIMITED BY SIZE
       INTO OUTPUT-LINE-1
END-STRING.
 
STRING "Address: " DELIMITED BY SIZE
       STREET-ADDRESS DELIMITED BY SIZE
       INTO OUTPUT-LINE-2
END-STRING.
 
STRING "Location: " DELIMITED BY SIZE
       CITY DELIMITED BY SIZE
       ", " DELIMITED BY SIZE
       STATE DELIMITED BY SIZE
       " " DELIMITED BY SIZE
       ZIP-CODE DELIMITED BY SIZE
       INTO OUTPUT-LINE-3
END-STRING.

This example demonstrates how data movement verbs work together to parse and format a customer address.

Control Flow Verbs

Control flow verbs determine the sequence of operations in a COBOL program. They include branching statements, looping constructs, and procedural invocation verbs. These verbs give the program its logical structure.

IF

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IF BALANCE > 1000
   PERFORM PROCESS-PREMIUM-CUSTOMER
ELSE
   PERFORM PROCESS-REGULAR-CUSTOMER
END-IF.
 
IF AGE < 18
   MOVE "MINOR" TO CUSTOMER-CATEGORY
ELSE IF AGE < 65
   MOVE "ADULT" TO CUSTOMER-CATEGORY
ELSE
   MOVE "SENIOR" TO CUSTOMER-CATEGORY
END-IF.

Conditional execution based on a boolean expression.

EVALUATE

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EVALUATE TRUE
   WHEN BALANCE < 0
       PERFORM PROCESS-OVERDRAWN
   WHEN BALANCE = 0
       PERFORM PROCESS-ZERO-BALANCE
   WHEN BALANCE < 1000
       PERFORM PROCESS-LOW-BALANCE
   WHEN OTHER
       PERFORM PROCESS-NORMAL-BALANCE
END-EVALUATE.
 
EVALUATE TRANSACTION-CODE
   WHEN "D"
       PERFORM PROCESS-DEPOSIT
   WHEN "W"
       PERFORM PROCESS-WITHDRAWAL
   WHEN "T"
       PERFORM PROCESS-TRANSFER
   WHEN OTHER
       PERFORM PROCESS-ERROR
END-EVALUATE.

Multi-way branching, similar to a switch/case in other languages.

PERFORM

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*> Basic PERFORM
PERFORM CALCULATE-INTEREST.
 
*> PERFORM with THRU
PERFORM PROCESS-START THRU PROCESS-END.
 
*> PERFORM TIMES
PERFORM PRINT-HEADER 3 TIMES.
 
*> PERFORM UNTIL
PERFORM PROCESS-RECORD UNTIL END-OF-FILE.
 
*> PERFORM VARYING
PERFORM VARYING INDEX-1 FROM 1 BY 1
        UNTIL INDEX-1 > 10
   DISPLAY TABLE-ITEM(INDEX-1)
END-PERFORM.
 
*> In-line PERFORM
PERFORM UNTIL END-OF-FILE
   READ INPUT-FILE
      AT END SET END-OF-FILE TO TRUE
      NOT AT END PERFORM PROCESS-RECORD
   END-READ
END-PERFORM.

Executes paragraphs/sections or blocks of code, with various iteration options.

GO TO

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GO TO PARAGRAPH-NAME.
 
IF AMOUNT > 1000
   GO TO HIGH-AMOUNT-PARA
ELSE
   GO TO LOW-AMOUNT-PARA
END-IF.
 
GO TO PARA-1 PARA-2 PARA-3 DEPENDING ON CHOICE.

Transfers control to the specified paragraph or section (less used in modern code).

CALL

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CALL "SUBPROGRAM" USING PARAM1, PARAM2.
 
CALL "CUSTINFO" USING BY REFERENCE CUSTOMER-ID
                      BY CONTENT  QUERY-TYPE
                      BY REFERENCE RESULT-DATA.
 
CALL PROGRAM-NAME.
 
CALL "REPORT" USING REPORT-DATA
   ON EXCEPTION
      DISPLAY "Program not found"
   NOT ON EXCEPTION
      MOVE "Y" TO REPORT-COMPLETE
END-CALL.

Invokes a separate COBOL program or external routine.

EXIT, GOBACK, STOP RUN

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EXIT.  *> Marks the end of a paragraph
 
EXIT PROGRAM.  *> Returns from a called program
 
GOBACK.  *> Returns to the calling program or OS
 
STOP RUN.  *> Terminates the entire run unit
 
EXIT PERFORM.  *> Exits from the current PERFORM
 
EXIT PERFORM CYCLE.  *> Skips to the next iteration

Various ways to exit from different program structures.

Example: Complex Control Flow

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PROCEDURE DIVISION.
MAIN-PROCESS.
    PERFORM INITIALIZATION.
    PERFORM PROCESS-FILES UNTIL END-OF-FILES.
    PERFORM WRAP-UP.
    STOP RUN.
 
INITIALIZATION.
    OPEN INPUT CUSTOMER-FILE.
    OPEN OUTPUT REPORT-FILE.
    MOVE "N" TO END-OF-FILES.
    PERFORM READ-CUSTOMER-RECORD.
 
READ-CUSTOMER-RECORD.
    READ CUSTOMER-FILE
        AT END MOVE "Y" TO END-OF-FILES
        NOT AT END PERFORM VALIDATE-CUSTOMER-RECORD
    END-READ.
 
PROCESS-FILES.
    EVALUATE TRUE
        WHEN VALID-CUSTOMER
            PERFORM PROCESS-VALID-CUSTOMER
        WHEN INACTIVE-CUSTOMER
            PERFORM PROCESS-INACTIVE-CUSTOMER
        WHEN OTHER
            PERFORM PROCESS-INVALID-CUSTOMER
    END-EVALUATE.
    PERFORM READ-CUSTOMER-RECORD.
 
VALIDATE-CUSTOMER-RECORD.
    MOVE "N" TO VALID-CUSTOMER-SW.
    MOVE "N" TO INACTIVE-CUSTOMER-SW.
    
    IF CUSTOMER-ID IS NUMERIC
        IF CUSTOMER-STATUS = "A"
            MOVE "Y" TO VALID-CUSTOMER-SW
        ELSE IF CUSTOMER-STATUS = "I"
            MOVE "Y" TO INACTIVE-CUSTOMER-SW
        END-IF
    END-IF.
 
PROCESS-VALID-CUSTOMER.
    IF CUSTOMER-BALANCE > 10000
        PERFORM PROCESS-HIGH-BALANCE-CUSTOMER
    ELSE IF CUSTOMER-BALANCE < 0
        PERFORM PROCESS-OVERDRAWN-CUSTOMER
    ELSE
        PERFORM PROCESS-NORMAL-CUSTOMER
    END-IF.
 
PROCESS-INACTIVE-CUSTOMER.
    MOVE CUSTOMER-ID TO INACTIVE-REPORT-ID.
    MOVE CUSTOMER-NAME TO INACTIVE-REPORT-NAME.
    MOVE "INACTIVE ACCOUNT" TO INACTIVE-REPORT-MESSAGE.
    WRITE INACTIVE-REPORT-RECORD.
    ADD 1 TO INACTIVE-COUNTER.
 
PROCESS-INVALID-CUSTOMER.
    MOVE CUSTOMER-ID TO ERROR-REPORT-ID.
    MOVE "INVALID CUSTOMER RECORD" TO ERROR-REPORT-MESSAGE.
    WRITE ERROR-REPORT-RECORD.
    ADD 1 TO ERROR-COUNTER.
 
PROCESS-HIGH-BALANCE-CUSTOMER.
    CALL "PREMIUM-PROCESSING" USING CUSTOMER-RECORD
                                    PREMIUM-STATUS.
    IF PREMIUM-STATUS = "OK"
        ADD 1 TO PREMIUM-COUNTER
    ELSE
        PERFORM PROCESS-NORMAL-CUSTOMER
    END-IF.
 
PROCESS-OVERDRAWN-CUSTOMER.
    MOVE CUSTOMER-ID TO OVERDRAWN-REPORT-ID.
    MOVE CUSTOMER-NAME TO OVERDRAWN-REPORT-NAME.
    MOVE CUSTOMER-BALANCE TO OVERDRAWN-REPORT-BALANCE.
    WRITE OVERDRAWN-REPORT-RECORD.
    ADD 1 TO OVERDRAWN-COUNTER.
 
PROCESS-NORMAL-CUSTOMER.
    MOVE CUSTOMER-ID TO NORMAL-REPORT-ID.
    MOVE CUSTOMER-NAME TO NORMAL-REPORT-NAME.
    MOVE CUSTOMER-BALANCE TO NORMAL-REPORT-BALANCE.
    WRITE NORMAL-REPORT-RECORD.
    ADD 1 TO NORMAL-COUNTER.
 
WRAP-UP.
    CLOSE CUSTOMER-FILE.
    CLOSE REPORT-FILE.
    DISPLAY "Processing complete.".
    DISPLAY NORMAL-COUNTER " normal accounts processed.".
    DISPLAY PREMIUM-COUNTER " premium accounts processed.".
    DISPLAY OVERDRAWN-COUNTER " overdrawn accounts processed.".
    DISPLAY INACTIVE-COUNTER " inactive accounts processed.".
    DISPLAY ERROR-COUNTER " error records found."

This example demonstrates how various control flow verbs work together in a real-world program.

I/O Verbs

Input/Output verbs handle file operations and interaction with external data sources. These verbs allow COBOL programs to read from and write to files, which is essential for batch processing and data management.

OPEN

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OPEN INPUT CUSTOMER-FILE.
OPEN OUTPUT REPORT-FILE.
OPEN I-O MASTER-FILE.
OPEN EXTEND LOG-FILE.
OPEN INPUT CUSTOMER-FILE
      OUTPUT REPORT-FILE
      I-O TRANSACTION-FILE.

Prepares files for processing with different access modes.

CLOSE

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CLOSE CUSTOMER-FILE.
CLOSE REPORT-FILE TRANSACTION-FILE.
CLOSE MASTER-FILE WITH LOCK.

Terminates file processing and releases resources.

READ

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READ CUSTOMER-FILE.
 
READ CUSTOMER-FILE
    AT END MOVE "Y" TO EOF-FLAG
END-READ.
 
READ CUSTOMER-FILE NEXT RECORD.
 
READ INDEXED-FILE KEY IS CUSTOMER-ID
    INVALID KEY PERFORM CUSTOMER-NOT-FOUND
END-READ.
 
READ INDEXED-FILE WITH LOCK
    KEY IS CUSTOMER-ID.

Retrieves records from a file, with sequential or random access.

WRITE

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WRITE CUSTOMER-RECORD.
 
WRITE CUSTOMER-RECORD
    INVALID KEY PERFORM DUPLICATE-KEY
END-WRITE.
 
WRITE REPORT-RECORD
    AFTER ADVANCING 2 LINES.
 
WRITE REPORT-RECORD
    BEFORE ADVANCING PAGE.

Creates new records in a file, with format control for print files.

REWRITE

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REWRITE CUSTOMER-RECORD.
 
REWRITE CUSTOMER-RECORD
    INVALID KEY PERFORM RECORD-NOT-FOUND
END-REWRITE.
 
REWRITE CUSTOMER-RECORD
    FROM UPDATED-CUSTOMER.

Updates existing records in a file (requires prior READ).

DELETE

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DELETE CUSTOMER-FILE.
 
DELETE CUSTOMER-FILE RECORD
    INVALID KEY PERFORM RECORD-NOT-FOUND
END-DELETE.

Removes records from a file (requires prior READ for sequential files).

START

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START INDEXED-FILE
    KEY IS GREATER THAN CUSTOMER-ID
    INVALID KEY PERFORM NO-MATCHING-RECORDS
END-START.
 
START INDEXED-FILE
    KEY IS NOT LESS THAN CUSTOMER-ID.
 
START INDEXED-FILE
    KEY IS = CUSTOMER-ID.

Positions an indexed or relative file for sequential retrieval with key conditions.

ACCEPT / DISPLAY

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ACCEPT CUSTOMER-ID.
 
ACCEPT CURRENT-DATE FROM DATE.
ACCEPT SYSTEM-TIME FROM TIME.
 
DISPLAY "Enter customer ID: ".
DISPLAY "Total records: " RECORD-COUNT.

Simple console input/output operations (technically not file I/O but related to external interaction).

Example: Complete File Processing

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IDENTIFICATION DIVISION.
PROGRAM-ID. FILE-UPDATE.
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
    SELECT CUSTOMER-FILE ASSIGN TO "CUSTOMER.DAT"
        ORGANIZATION IS INDEXED
        ACCESS MODE IS DYNAMIC
        RECORD KEY IS CUST-ID
        FILE STATUS IS CUST-FILE-STATUS.
    SELECT TRANSACTION-FILE ASSIGN TO "TRANSACT.DAT"
        ORGANIZATION IS SEQUENTIAL
        ACCESS IS SEQUENTIAL
        FILE STATUS IS TRANS-FILE-STATUS.
    SELECT REPORT-FILE ASSIGN TO "REPORT.DAT"
        ORGANIZATION IS SEQUENTIAL
        FILE STATUS IS REPORT-FILE-STATUS.
DATA DIVISION.
FILE SECTION.
FD CUSTOMER-FILE.
01 CUSTOMER-RECORD.
   05 CUST-ID         PIC X(6).
   05 CUST-NAME       PIC X(30).
   05 CUST-BALANCE    PIC S9(7)V99.
   05 CUST-STATUS     PIC X.
 
FD TRANSACTION-FILE.
01 TRANSACTION-RECORD.
   05 TRANS-CODE      PIC X.
      88 ADD-RECORD      VALUE 'A'.
      88 CHANGE-RECORD   VALUE 'C'.
      88 DELETE-RECORD   VALUE 'D'.
   05 TRANS-CUST-ID   PIC X(6).
   05 TRANS-DATA      PIC X(50).
 
FD REPORT-FILE.
01 REPORT-RECORD      PIC X(80).
 
WORKING-STORAGE SECTION.
01 FILE-STATUS-FIELDS.
   05 CUST-FILE-STATUS   PIC XX.
   05 TRANS-FILE-STATUS  PIC XX.
   05 REPORT-FILE-STATUS PIC XX.
 
01 FLAGS.
   05 EOF-TRANS-FILE     PIC X VALUE 'N'.
      88 END-OF-TRANS      VALUE 'Y'.
 
01 HEADER-LINE.
   05 FILLER            PIC X(20) VALUE 'TRANSACTION REPORT - '.
   05 HEADER-DATE       PIC X(10).
   05 FILLER            PIC X(50) VALUE SPACES.
 
01 DETAIL-LINE.
   05 DL-TRANS-CODE     PIC X(8).
   05 DL-CUST-ID        PIC X(10).
   05 DL-CUST-NAME      PIC X(30).
   05 DL-STATUS         PIC X(15).
   05 FILLER            PIC X(17) VALUE SPACES.
 
PROCEDURE DIVISION.
MAIN-PROCESS.
    PERFORM INITIALIZATION.
    PERFORM PROCESS-TRANSACTIONS UNTIL END-OF-TRANS.
    PERFORM WRAP-UP.
    STOP RUN.
 
INITIALIZATION.
    OPEN I-O CUSTOMER-FILE.
    IF CUST-FILE-STATUS NOT = "00"
       DISPLAY "Error opening customer file: " CUST-FILE-STATUS
       STOP RUN
    END-IF.
    
    OPEN INPUT TRANSACTION-FILE.
    IF TRANS-FILE-STATUS NOT = "00"
       DISPLAY "Error opening transaction file: " TRANS-FILE-STATUS
       CLOSE CUSTOMER-FILE
       STOP RUN
    END-IF.
    
    OPEN OUTPUT REPORT-FILE.
    IF REPORT-FILE-STATUS NOT = "00"
       DISPLAY "Error opening report file: " REPORT-FILE-STATUS
       CLOSE CUSTOMER-FILE
       CLOSE TRANSACTION-FILE
       STOP RUN
    END-IF.
    
    ACCEPT HEADER-DATE FROM DATE.
    MOVE HEADER-LINE TO REPORT-RECORD.
    WRITE REPORT-RECORD.
    
    MOVE SPACES TO REPORT-RECORD.
    WRITE REPORT-RECORD.
    
    MOVE "ACTION   CUST ID   CUSTOMER NAME               STATUS" 
      TO REPORT-RECORD.
    WRITE REPORT-RECORD.
    
    MOVE SPACES TO REPORT-RECORD.
    WRITE REPORT-RECORD.
    
    READ TRANSACTION-FILE
        AT END MOVE 'Y' TO EOF-TRANS-FILE
    END-READ.
 
PROCESS-TRANSACTIONS.
    EVALUATE TRANS-CODE
        WHEN 'A'
            PERFORM ADD-CUSTOMER
        WHEN 'C'
            PERFORM CHANGE-CUSTOMER
        WHEN 'D'
            PERFORM DELETE-CUSTOMER
        WHEN OTHER
            MOVE "INVALID" TO DL-STATUS
            PERFORM WRITE-REPORT-LINE
    END-EVALUATE.
    
    READ TRANSACTION-FILE
        AT END MOVE 'Y' TO EOF-TRANS-FILE
    END-READ.
 
ADD-CUSTOMER.
    MOVE TRANS-CUST-ID TO CUST-ID.
    READ CUSTOMER-FILE
        INVALID KEY PERFORM ADD-NEW-CUSTOMER
        NOT INVALID KEY
            MOVE "DUPLICATE" TO DL-STATUS
            PERFORM WRITE-REPORT-LINE
    END-READ.
 
ADD-NEW-CUSTOMER.
    MOVE TRANS-CUST-ID TO CUST-ID.
    MOVE SPACES TO CUST-NAME.
    MOVE ZEROS TO CUST-BALANCE.
    MOVE "A" TO CUST-STATUS.
    
    MOVE TRANS-DATA TO CUST-NAME.
    
    WRITE CUSTOMER-RECORD
        INVALID KEY
            MOVE "ERROR-WRITE" TO DL-STATUS
        NOT INVALID KEY
            MOVE "ADDED" TO DL-STATUS
    END-WRITE.
    
    PERFORM WRITE-REPORT-LINE.
 
CHANGE-CUSTOMER.
    MOVE TRANS-CUST-ID TO CUST-ID.
    READ CUSTOMER-FILE
        INVALID KEY
            MOVE "NOT FOUND" TO DL-STATUS
            PERFORM WRITE-REPORT-LINE
        NOT INVALID KEY
            PERFORM UPDATE-CUSTOMER-RECORD
    END-READ.
 
UPDATE-CUSTOMER-RECORD.
    MOVE TRANS-DATA TO CUST-NAME.
    
    REWRITE CUSTOMER-RECORD
        INVALID KEY
            MOVE "ERROR-REWRITE" TO DL-STATUS
        NOT INVALID KEY
            MOVE "UPDATED" TO DL-STATUS
    END-REWRITE.
    
    PERFORM WRITE-REPORT-LINE.
 
DELETE-CUSTOMER.
    MOVE TRANS-CUST-ID TO CUST-ID.
    READ CUSTOMER-FILE
        INVALID KEY
            MOVE "NOT FOUND" TO DL-STATUS
            PERFORM WRITE-REPORT-LINE
        NOT INVALID KEY
            PERFORM REMOVE-CUSTOMER-RECORD
    END-READ.
 
REMOVE-CUSTOMER-RECORD.
    DELETE CUSTOMER-FILE RECORD
        INVALID KEY
            MOVE "ERROR-DELETE" TO DL-STATUS
        NOT INVALID KEY
            MOVE "DELETED" TO DL-STATUS
    END-DELETE.
    
    PERFORM WRITE-REPORT-LINE.
 
WRITE-REPORT-LINE.
    EVALUATE TRANS-CODE
        WHEN 'A'
            MOVE "ADD" TO DL-TRANS-CODE
        WHEN 'C'
            MOVE "CHANGE" TO DL-TRANS-CODE
        WHEN 'D'
            MOVE "DELETE" TO DL-TRANS-CODE
        WHEN OTHER
            MOVE "UNKNOWN" TO DL-TRANS-CODE
    END-EVALUATE.
    
    MOVE TRANS-CUST-ID TO DL-CUST-ID.
    
    IF DL-STATUS = "NOT FOUND" OR DL-STATUS = "INVALID"
        MOVE SPACES TO DL-CUST-NAME
    ELSE
        MOVE CUST-NAME TO DL-CUST-NAME
    END-IF.
    
    MOVE DETAIL-LINE TO REPORT-RECORD.
    WRITE REPORT-RECORD.
 
WRAP-UP.
    CLOSE CUSTOMER-FILE.
    CLOSE TRANSACTION-FILE.
    
    MOVE SPACES TO REPORT-RECORD.
    WRITE REPORT-RECORD.
    MOVE "END OF REPORT" TO REPORT-RECORD.
    WRITE REPORT-RECORD.
    
    CLOSE REPORT-FILE.
    DISPLAY "Processing complete."

This comprehensive example demonstrates all the file I/O verbs working together in a typical batch update program.

Table Handling Verbs

Table handling verbs manage array-like structures in COBOL. These verbs allow programs to efficiently search, sort, and manipulate tables, which is essential for working with collections of similar data.

SEARCH

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SEARCH PRODUCT-TABLE
    AT END MOVE "N" TO FOUND-SW
    WHEN PRODUCT-CODE(IDX) = SEARCH-CODE
        MOVE "Y" TO FOUND-SW
        MOVE PRODUCT-DESC(IDX) TO OUTPUT-DESC
END-SEARCH.

Sequential search through a table.

SEARCH ALL

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SEARCH ALL PRODUCT-TABLE
    AT END MOVE "N" TO FOUND-SW
    WHEN PRODUCT-CODE(IDX) = SEARCH-CODE
        MOVE "Y" TO FOUND-SW
        MOVE PRODUCT-DESC(IDX) TO OUTPUT-DESC
END-SEARCH.

Binary search (table must be sorted by the key).

SET

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SET IDX TO 1.
SET PRODUCT-INDEX TO 5.
SET IDX UP BY 1.
SET IDX DOWN BY 2.
SET TAX-TABLE-IDX TO STATE-IDX.

Manipulates index values for table access.

SORT

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SORT SORT-FILE
    ON ASCENDING KEY SORT-KEY
    USING INPUT-FILE
    GIVING OUTPUT-FILE.
 
SORT SORT-FILE
    ON DESCENDING KEY SORT-DEPT
    ON ASCENDING KEY SORT-NAME
    INPUT PROCEDURE IS PROCESS-INPUT
    OUTPUT PROCEDURE IS PROCESS-OUTPUT.

Sorts records from a file, with optional processing.

Example: Table Processing

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IDENTIFICATION DIVISION.
PROGRAM-ID. TABLE-DEMO.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 STATE-TABLE.
   05 STATE-ENTRY OCCURS 50 TIMES
      INDEXED BY STATE-IDX.
      10 STATE-CODE        PIC XX.
      10 STATE-NAME        PIC X(20).
      10 STATE-CAPITAL     PIC X(20).
      10 STATE-POPULATION  PIC 9(8).
 
01 COUNTER                PIC 99 VALUE ZERO.
01 SEARCH-STATE           PIC XX.
01 FOUND-SW               PIC X VALUE 'N'.
   88 STATE-FOUND           VALUE 'Y'.
   88 STATE-NOT-FOUND       VALUE 'N'.
 
PROCEDURE DIVISION.
MAIN-PROCESS.
    PERFORM INITIALIZE-TABLE.
    DISPLAY "Enter state code to lookup (XX to end): ".
    ACCEPT SEARCH-STATE.
    
    PERFORM UNTIL SEARCH-STATE = "XX"
        PERFORM SEARCH-FOR-STATE
        IF STATE-FOUND
            DISPLAY "State: " STATE-NAME(STATE-IDX)
            DISPLAY "Capital: " STATE-CAPITAL(STATE-IDX)
            DISPLAY "Population: " STATE-POPULATION(STATE-IDX)
        ELSE
            DISPLAY "State code not found"
        END-IF
        
        DISPLAY "Enter state code to lookup (XX to end): "
        ACCEPT SEARCH-STATE
    END-PERFORM.
    
    DISPLAY "Demonstration of SET and reference modification:"
    PERFORM VARYING STATE-IDX FROM 1 BY 1
            UNTIL STATE-IDX > COUNTER
        IF STATE-CODE(STATE-IDX)(1:1) = "A"
            DISPLAY STATE-NAME(STATE-IDX)
        END-IF
    END-PERFORM.
    
    STOP RUN.
 
INITIALIZE-TABLE.
    *> Populate some sample data
    SET STATE-IDX TO 1.
    MOVE "AL" TO STATE-CODE(STATE-IDX).
    MOVE "Alabama" TO STATE-NAME(STATE-IDX).
    MOVE "Montgomery" TO STATE-CAPITAL(STATE-IDX).
    MOVE 5024279 TO STATE-POPULATION(STATE-IDX).
    
    SET STATE-IDX UP BY 1.
    MOVE "AK" TO STATE-CODE(STATE-IDX).
    MOVE "Alaska" TO STATE-NAME(STATE-IDX).
    MOVE "Juneau" TO STATE-CAPITAL(STATE-IDX).
    MOVE 733391 TO STATE-POPULATION(STATE-IDX).
    
    SET STATE-IDX UP BY 1.
    MOVE "AZ" TO STATE-CODE(STATE-IDX).
    MOVE "Arizona" TO STATE-NAME(STATE-IDX).
    MOVE "Phoenix" TO STATE-CAPITAL(STATE-IDX).
    MOVE 7151502 TO STATE-POPULATION(STATE-IDX).
    
    SET STATE-IDX UP BY 1.
    MOVE "AR" TO STATE-CODE(STATE-IDX).
    MOVE "Arkansas" TO STATE-NAME(STATE-IDX).
    MOVE "Little Rock" TO STATE-CAPITAL(STATE-IDX).
    MOVE 3011524 TO STATE-POPULATION(STATE-IDX).
    
    SET STATE-IDX UP BY 1.
    MOVE "CA" TO STATE-CODE(STATE-IDX).
    MOVE "California" TO STATE-NAME(STATE-IDX).
    MOVE "Sacramento" TO STATE-CAPITAL(STATE-IDX).
    MOVE 39538223 TO STATE-POPULATION(STATE-IDX).
    
    MOVE STATE-IDX TO COUNTER.
 
SEARCH-FOR-STATE.
    MOVE 'N' TO FOUND-SW.
    SET STATE-IDX TO 1.
    
    SEARCH STATE-ENTRY
        AT END
            SET STATE-NOT-FOUND TO TRUE
        WHEN STATE-CODE(STATE-IDX) = SEARCH-STATE
            SET STATE-FOUND TO TRUE
    END-SEARCH.

This example demonstrates how to use SEARCH and SET to work with COBOL tables.

Exercise: Identifying and Using COBOL Verbs

Practice identifying and using COBOL verbs with the following exercises:

Exercise 1: Identify Verb Categories

Identify the category of each COBOL verb in the following program:

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PROCEDURE DIVISION.
MAIN-PROCESS.
    OPEN INPUT CUSTOMER-FILE.
    OPEN OUTPUT REPORT-FILE.
    
    MOVE ZEROS TO RECORD-COUNT.
    MOVE SPACES TO REPORT-HEADER.
    
    READ CUSTOMER-FILE
        AT END MOVE 'Y' TO EOF-FLAG
    END-READ.
    
    PERFORM UNTIL EOF-FLAG = 'Y'
        ADD 1 TO RECORD-COUNT
        IF CUSTOMER-BALANCE > 1000
            COMPUTE INTEREST = CUSTOMER-BALANCE * 0.05
            MOVE CUSTOMER-ID TO REPORT-CUSTOMER-ID
            MOVE CUSTOMER-NAME TO REPORT-CUSTOMER-NAME
            MOVE INTEREST TO REPORT-INTEREST
            WRITE REPORT-RECORD
        END-IF
        
        READ CUSTOMER-FILE
            AT END MOVE 'Y' TO EOF-FLAG
        END-READ
    END-PERFORM.
    
    DISPLAY "Processed " RECORD-COUNT " records.".
    
    CLOSE CUSTOMER-FILE.
    CLOSE REPORT-FILE.
    
    STOP RUN.

Exercise 2: Complete the Program

Fill in the missing COBOL verbs to make this program work correctly:

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PROCEDURE DIVISION.
MAIN-PROCESS.
    _______ INITIALIZATION.
    _______ PROCESS-DATA UNTIL END-OF-FILE.
    _______ FINALIZATION.
    _______ RUN.
 
INITIALIZATION.
    _______ INPUT CUSTOMER-FILE.
    _______ OUTPUT REPORT-FILE.
    _______ ZEROS TO TOTAL-BALANCE.
    _______ SPACES TO PRINT-LINE.
    _______ CUSTOMER-RECORD
        AT END _______ 'Y' TO END-OF-FILE
    END-READ.
 
PROCESS-DATA.
    _______ CUSTOMER-ID TO PRINT-ID.
    _______ CUSTOMER-NAME TO PRINT-NAME.
    _______ CUSTOMER-BALANCE TO PRINT-BALANCE.
    _______ TOTAL-BALANCE BY CUSTOMER-BALANCE.
    
    _______ PRINT-RECORD.
    
    _______ CUSTOMER-RECORD
        AT END _______ 'Y' TO END-OF-FILE
    END-READ.
 
FINALIZATION.
    _______ "Total balance: " TOTAL-BALANCE.
    _______ CUSTOMER-FILE.
    _______ REPORT-FILE.

Exercise 3: Create a Program

Write a COBOL program that reads a file of product records, sorts them by product category and then by price, and writes a formatted report. Try to use at least one verb from each category we've covered.

Test Your Knowledge

1. Which category of COBOL verbs is primarily used for arithmetic operations?

I/O verbs
Computational verbs
Control flow verbs
Data movement verbs

2. What is the primary purpose of the MOVE verb in COBOL?

To perform arithmetic operations
To transfer control to another part of the program
To copy data from one memory location to another
To handle file input and output

3. Which COBOL verb is used to execute a paragraph or section and then return control?

GO TO
CALL
PERFORM
EXECUTE

4. Which of the following is NOT a valid I/O verb in COBOL?

READ
WRITE
OPEN
TRANSFER

5. What is the purpose of the SEARCH verb in COBOL?

To search through text strings for specific characters
To find records in a file based on key values
To look up values in a table or array
To scan the program for syntax errors

Frequently Asked Questions

PROCEDURE DIVISION Structure Basic Arithmetic Operations

COBOL Tutorial

COBOL Verbs Overview

Introduction to COBOL Verbs

Basic Verb Structure

Computational Verbs

ADD

SUBTRACT

MULTIPLY

DIVIDE

COMPUTE

Common Features of Computational Verbs

Example: Using Multiple Computational Verbs

Data Movement Verbs

MOVE

INITIALIZE

STRING

UNSTRING

INSPECT

SET

MOVE CORRESPONDING

Example: Complex String Processing

Control Flow Verbs

IF

EVALUATE

PERFORM

GO TO

CALL

EXIT, GOBACK, STOP RUN

Example: Complex Control Flow

I/O Verbs

OPEN

CLOSE

READ

WRITE

REWRITE

DELETE

START

ACCEPT / DISPLAY

Example: Complete File Processing

Table Handling Verbs

SEARCH

SEARCH ALL

SET

SORT

Example: Table Processing

Exercise: Identifying and Using COBOL Verbs

Exercise 1: Identify Verb Categories

Exercise 2: Complete the Program

Exercise 3: Create a Program

Test Your Knowledge

Frequently Asked Questions

What is the difference between MOVE and COMPUTE in COBOL?

Can I mix different categories of COBOL verbs in a single paragraph?

How do I choose between PERFORM and CALL when organizing my COBOL program?

What happens if a computational verb results in an overflow?

Are there any deprecated COBOL verbs I should avoid in modern programs?