Ques 1. What is COBOL?

COBOL (Common Business-Oriented Language) is a high-level programming language used primarily for business, finance, and administrative systems.

Ques 2. What is the significance of the PERFORM statement?

The PERFORM statement is used for loop control in COBOL. It allows the repeated execution of a set of statements until a specified condition is met.

Example:

PERFORM 5 TIMES
  DISPLAY 'Hello, World!'
END-PERFORM.

Ques 3. What is the purpose of the INITIALIZE verb?

The INITIALIZE verb is used to set the initial values for data items in COBOL. It initializes numeric items to zero and alphanumeric items to spaces.

Example:

01 COUNT PIC 9(3).
INITIALIZE COUNT.

Ques 4. What is the purpose of the FILE SECTION in COBOL?

The FILE SECTION in COBOL is used to describe the structure and attributes of files used by the program. It includes the FD (File Description) entries.

Ques 5. How does COBOL handle decimal arithmetic?

COBOL provides the COMPUTE statement for decimal arithmetic. It allows the programmer to perform arithmetic operations on numeric data items with explicit precision.

Example:

COMPUTE TOTAL = AMOUNT-1 + AMOUNT-2.

Ques 6. What is the purpose of the LEVEL number in COBOL?

The LEVEL number in COBOL is used to indicate the hierarchy and nesting level of data items. It determines the structure and organization of data in the Data Division.

Example:

01 EMPLOYEE-RECORD.
  05 EMPLOYEE-ID PIC 9(5).
  05 EMPLOYEE-NAME PIC X(20).

Ques 7. How is data movement done in COBOL?

Data movement in COBOL is achieved through the MOVE verb. It transfers the value of one data item to another, and it can handle various data types.

Example:

MOVE 100 TO AMOUNT.

Ques 8. How does COBOL support file processing?

COBOL supports file processing through file control entries in the File Section. The OPEN, READ, WRITE, and CLOSE statements are used for file operations.

Example:

OPEN INPUT FILE-1.
READ FILE-1 INTO DATA-RECORD.
CLOSE FILE-1.

Ques 9. What is the purpose of the SET statement in COBOL?

The SET statement in COBOL is used to assign values to index names, condition names, and other special registers. It is essential for controlling program flow.

Example:

SET EMPLOYEE-INDEX TO 1.

Ques 10. Explain the concept of the INITIALIZE verb.

The INITIALIZE verb in COBOL is used to set the initial values for data items. It initializes numeric items to zero and alphanumeric items to spaces.

Example:

01 COUNT PIC 9(3).
INITIALIZE COUNT.

Ques 11. What is the purpose of the COPY statement in COBOL?

The COPY statement in COBOL is used for including copybooks in the source code. It allows the reuse of common code and improves maintainability.

Example:

COPY 'COMMON-FILE'.

Ques 12. Explain the concept of the ACCEPT statement.

The ACCEPT statement in COBOL is used for interactive input. It allows the program to receive data directly from the user during runtime.

Example:

ACCEPT EMPLOYEE-NAME.

Ques 13. What is the role of the WORKING-STORAGE section in COBOL?

The WORKING-STORAGE section in COBOL is used to declare variables that retain their values throughout the execution of the program. It provides working storage for temporary data.

Example:

WORKING-STORAGE SECTION.
01 COUNTER PIC 9(3) VALUE 0.

Ques 14. Explain the concept of the CALL statement in COBOL.

The CALL statement in COBOL is used to invoke subprograms or procedures from other programs. It allows modular programming and code reuse.

Example:

CALL 'SUB-PROGRAM' USING PARAMETER-1 PARAMETER-2.

Ques 15. What is the role of the END-IF statement in COBOL?

The END-IF statement in COBOL marks the end of an IF statement block. It is used to indicate the conclusion of the conditional code and resume normal program flow.

Example:

IF AMOUNT > LIMIT
  DISPLAY 'Amount exceeds limit'
END-IF.

Ques 16. Explain the concept of the ACCEPT FROM statement.

The ACCEPT FROM statement in COBOL is used to receive data directly from an external device, such as a keyboard. It simplifies interactive input operations.

Example:

ACCEPT WS-EMPLOYEE-ID FROM 'Enter Employee ID:'.

Ques 17. Explain the concept of the COMPUTATIONAL-3 clause.

The COMPUTATIONAL-3 (COMP-3) clause in COBOL is used to define packed-decimal data items. It represents decimal numbers in a packed format for efficient storage.

Example:

01 AMOUNT PIC 9(5) COMP-3.

Ques 18. Explain the Division structure in COBOL.

The Division structure in COBOL consists of Identification, Environment, Data, and Procedure divisions. These divisions help organize the program's structure.

Ques 19. Differentiate between COMP and COMP-3 in COBOL.

COMP and COMP-3 are data types in COBOL. COMP is used for binary representation, while COMP-3 is used for packed decimal representation.

Ques 20. Explain the difference between CALL and PERFORM in COBOL.

CALL is used to transfer control to another program or a specific paragraph within the same program. PERFORM is used for looping and invoking paragraphs or sections.

Ques 21. How is indexing done in COBOL?

Indexing in COBOL is typically done using INDEXED BY clause. It associates an index name with a data item, allowing for efficient access to table elements.

Example:

01 EMPLOYEE-TABLE OCCURS 10 TIMES INDEXED BY EMPLOYEE-INDEX.
...

Ques 22. Explain the difference between static and dynamic calls in COBOL.

Static calls are resolved at compile-time, while dynamic calls are resolved at run-time. CALL and PERFORM are examples of static calls, while CALL 'subprogram' USING ... is a dynamic call.

Ques 23. Explain the concept of 88 level in COBOL.

The 88 level in COBOL is used for condition names. It allows the programmer to associate a condition with a data item, simplifying the writing of conditionals.

Example:

01 STATUS-CODE PIC 99.
88 SUCCESS VALUE 00.
88 FAILURE VALUE 01.

Ques 24. What is the significance of the OCCURS clause?

The OCCURS clause in COBOL is used to define arrays or tables. It specifies the number of occurrences or elements, allowing for efficient handling of repetitive data.

Example:

01 SALES-AMOUNT OCCURS 12 TIMES PIC 9(5).

Ques 25. Explain the INSPECT verb in COBOL.

The INSPECT verb in COBOL is used for string manipulation. It allows the programmer to search, replace, or delete characters in a string.

Example:

INSPECT NAME-STRING REPLACING ALL '- ' BY SPACE.

Ques 26. Explain the EVALUATE statement in COBOL.

The EVALUATE statement in COBOL is used for multi-way branching. It simplifies complex nested IF statements and enhances code readability.

Example:

EVALUATE TRUE
  WHEN AGE < 18 DISPLAY 'Minor'
  WHEN AGE > 65 DISPLAY 'Senior'
  WHEN OTHER DISPLAY 'Adult'.

Ques 27. Explain the concept of the INDEXED BY clause.

The INDEXED BY clause in COBOL is used to associate an index name with a table or array. It provides a way to reference individual elements efficiently.

Example:

01 EMPLOYEE-TABLE OCCURS 10 TIMES INDEXED BY EMPLOYEE-INDEX.
...

Ques 28. Explain the concept of the PERFORM VARYING statement.

The PERFORM VARYING statement in COBOL is used for iterative processing. It allows a specified set of statements to be repeated while incrementing or decrementing a loop variable.

Example:

PERFORM VARYING I FROM 1 BY 1 UNTIL I > 10
  DISPLAY 'Iteration ' I.
END-PERFORM.

Ques 29. How do you handle date and time in COBOL?

COBOL provides the special registers CURRENT-DATE and CURRENT-TIME to handle date and time operations. These registers store system date and time values.

Example:

MOVE FUNCTION CURRENT-DATE TO DATE-FIELD.

Ques 30. How does COBOL support data validation?

COBOL supports data validation through the use of conditions, the IF statement, and the EVALUATE statement. These constructs help ensure data integrity.

Example:

IF AMOUNT < 0
  DISPLAY 'Invalid amount'
END-IF.

Ques 31. Explain the purpose of the EXIT statement.

The EXIT statement in COBOL is used to terminate a loop prematurely. It allows the program to exit a PERFORM loop or a Section before reaching the normal end.

Example:

PERFORM UNTIL EOF-FLAG = 'Y'
  ...
  IF SOME-CONDITION
    EXIT.
  END-IF.
END-PERFORM.

Ques 32. Explain the purpose of the USAGE clause in COBOL.

The USAGE clause in COBOL is used to specify the internal representation of data items. It defines how data is stored in memory, such as binary, packed-decimal, or display.

Example:

01 AMOUNT PIC 9(5) USAGE COMP-3.

Ques 33. What is the significance of the MOVE CORRESPONDING statement?

The MOVE CORRESPONDING statement in COBOL is used to move corresponding data items from one record to another. It simplifies the process of copying similar fields between records.

Example:

MOVE CORRESPONDING RECORD-1 TO RECORD-2.

Ques 34. What is the purpose of the SEARCH statement in COBOL?

The SEARCH statement in COBOL is used to search a table for a specified value. It is commonly used with the WHEN clause to perform conditional actions based on the search result.

Example:

SEARCH ITEM-TABLE AT END DISPLAY 'Item not found'.

Ques 35. Explain the concept of the STRING statement in COBOL.

The STRING statement in COBOL is used for string concatenation. It allows the programmer to concatenate and manipulate character strings efficiently.

Example:

STRING 'Hello' ' ' 'World' DELIMITED BY SIZE INTO OUTPUT-STRING.

Ques 36. Explain the concept of the UNSTRING statement in COBOL.

The UNSTRING statement in COBOL is used to break down a delimited string into its individual components. It is useful for parsing and extracting data from strings.

Example:

UNSTRING NAME-STRING DELIMITED BY ',' INTO FIRST-NAME LAST-NAME.

Ques 37. Explain the concept of the INDEX in COBOL.

The INDEX in COBOL is a special register that is used to store the position within a table. It is often manipulated using the SET and PERFORM statements.

Example:

SET TABLE-INDEX TO 1.

Ques 38. What is the purpose of the EXIT PARAGRAPH statement?

The EXIT PARAGRAPH statement in COBOL is used to exit a specific paragraph prematurely. It is useful for controlling the flow within a section of code.

Example:

PERFORM PROCESS-DATA.
IF ERROR-FLAG = 'Y' THEN
  EXIT PARAGRAPH.
END-IF.

Ques 39. What is the purpose of the USE statement in COBOL?

The USE statement in COBOL is used to declare and specify the usage of indexes in a SEARCH statement. It associates an index with a table to optimize search operations.

Example:

USE EMPLOYEE-INDEX.

Ques 40. Explain the concept of the EXIT SECTION statement.

The EXIT SECTION statement in COBOL is used to terminate the current section prematurely. It allows the program to skip the remaining code within a particular section.

Example:

PERFORM PROCESS-DATA SECTION.
IF ERROR-FLAG = 'Y' THEN
  EXIT SECTION.
END-IF.

Ques 41. How do you handle errors in COBOL programs?

Errors in COBOL programs are often handled using the ON EXCEPTION clause or the use of condition names. This allows for the graceful handling of errors.

Example:

READ FILE-1 INTO WS-RECORD ON EXCEPTION
  DISPLAY 'Error reading file'
END-READ.

Ques 42. What is the purpose of the REDEFINES clause?

The REDEFINES clause in COBOL is used to share storage between two or more data items. It allows multiple data descriptions for the same physical storage.

Example:

01 EMPLOYEE-NAME PIC X(20).
01 EMPLOYEE-NAME-REDEFINED REDEFINES EMPLOYEE-NAME PIC 9(9).

Ques 43. What is the purpose of the MERGE statement?

The MERGE statement in COBOL is used to merge two or more sorted input files into a single sorted output file. It is often used for sorting and merging files.

Example:

MERGE FILE-1, FILE-2 INTO SORTED-FILE.

Ques 44. Explain the concept of the REWRITE statement in COBOL.

The REWRITE statement in COBOL is used to modify the contents of a record in a file. It is typically used in conjunction with the READ statement to update existing records.

Example:

READ FILE-1 INTO DATA-RECORD.
REWRITE DATA-RECORD.

Ques 45. What is the purpose of the EXIT PROGRAM statement?

The EXIT PROGRAM statement in COBOL is used to terminate the entire program. It is often used in conjunction with a condition or as part of an error-handling routine.

Example:

IF ERROR-FLAG = 'Y' THEN
  EXIT PROGRAM.
END-IF.

Ques 46. What is the significance of the RESERVE statement in COBOL?

The RESERVE statement in COBOL is used to allocate storage space for large data items. It ensures that sufficient memory is reserved to accommodate the specified data.

Example:

01 LARGE-DATA PIC X(1000).
RESERVE 1000 CHARACTERS FOR LARGE-DATA.

Ques 47. Explain the concept of the SET ENVIRONMENT statement.

The SET ENVIRONMENT statement in COBOL is used to specify or change environment settings, such as the currency symbol, decimal point character, or date format.

Example:

SET ENVIRONMENT CURRENCY-SYMBOL '$'.

Ques 48. What is the purpose of the REJECT statement in COBOL?

The REJECT statement in COBOL is used to return a record to an input file after it has been read. It is often used in conjunction with the REWRITE statement.

Example:

READ INPUT-FILE INTO DATA-RECORD.
IF CONDITION
  REJECT DATA-RECORD.
END-IF.

Ques 49. What is the purpose of the ALTER statement in COBOL?

The ALTER statement in COBOL is used to modify the properties of data items at runtime. It allows dynamic changes to the length, picture, or usage of data items.

Example:

ALTER ITEM-DESCR TO PIC X(30).

Ques 50. What is the purpose of the GENERATE statement in COBOL?

The GENERATE statement in COBOL is used to dynamically create new paragraphs or sections during program execution. It enhances the flexibility and adaptability of the program.

Example:

GENERATE 'NEW-PARAGRAPH'.