What is the difference between the PERFORM...THRU and PERFORM...VARYING statements in COBOL?
- PERFORM...THRU is used for conditional loops, while PERFORM...VARYING is used for unconditional loops
- PERFORM...THRU is used for iterative loops, while PERFORM...VARYING is used for nested loops
- PERFORM...THRU is used for nested loops, while PERFORM...VARYING is used for iterative loops
- There is no difference between PERFORM...THRU and PERFORM...VARYING
The PERFORM...THRU statement in COBOL is used for nested loops, allowing the programmer to execute a series of paragraphs or sections. On the other hand, PERFORM...VARYING is used for iterative loops, allowing the iteration through a range of values.
How does the CONTINUE statement impact the flow of control in a COBOL program?
- It repeats the current statement indefinitely
- It transfers control to a specific paragraph
- It transfers control to the next sequential statement
- It transfers control to the specified label
The CONTINUE statement in COBOL is a no-operation statement. It does not affect the flow of control and transfers it to the next sequential statement. It is often used for placeholder purposes or to improve code readability.
The _______ clause in a PERFORM statement is used to specify the condition for loop termination.
- TIMES
- UNTIL
- VARYING
- WITH
The UNTIL clause in a COBOL PERFORM loop allows you to specify a condition for loop termination. The loop will continue executing until the specified condition becomes true.
In COBOL, the FUNCTION ______ intrinsic function can be used to determine the current date.
- CURRENT-DATE
- DATE
- DAY
- TIME
The FUNCTION CURRENT-DATE in COBOL is used to retrieve the current date and time. It returns a data structure containing various components such as year, month, day, hour, minute, and second.
The "EVALUATE" statement can be used to simulate a _____ statement with multiple conditions.
- DIVIDE
- GOTO
- PERFORM
- Switch
The "EVALUATE" statement in COBOL serves a similar purpose as a "switch" statement in other programming languages. It allows for multiple conditions to be tested, providing a structured and efficient way to handle different cases.
In COBOL, what is the difference between the ADD and SUBTRACT statements when performing arithmetic operations?
- ADD adds values, and SUBTRACT subtracts values from the receiving field
- ADD and SUBTRACT are interchangeable in COBOL
- ADD is used for numeric addition, and SUBTRACT is used for alphanumeric subtraction
- ADD is used for subtraction, and SUBTRACT is used for addition
The ADD statement in COBOL is used for numeric addition, while the SUBTRACT statement is used for numeric subtraction. It's crucial to understand the distinction to perform accurate arithmetic operations in COBOL programs.
You are working on a COBOL program that performs a merge operation on two sorted files. How can you ensure that the merge operation is efficient and optimized for performance?
- Implementing a binary search algorithm
- Pre-sorting the input files before merging
- Using indexed files for both input files
- Using the SORT verb provided by COBOL
Pre-sorting the input files before merging ensures that the records are already in sorted order, which simplifies the merge process and improves performance. This reduces the need for complex sorting algorithms during the merge operation.
What is the primary purpose of the MOVE statement in COBOL?
- To control program flow
- To input data from the user
- To move data from one variable to another
- To perform arithmetic operations
The MOVE statement in COBOL is used to transfer data from one variable to another. It is essential for assigning values to variables and initializing data before processing.
When designing a modular COBOL application, you want to define a variable that will have scope across different programs but not be accessible from external applications. What approach would you choose?
- Declare the variable in the DATA DIVISION
- Use of copybooks
- Use of global variables
- Use of static variables
In COBOL, you can define a variable with scope across different programs by placing it in a copybook. Copybooks are reusable modules containing data definitions and are included in programs where the data is needed, ensuring data consistency and modularity while restricting access to external applications.
Your COBOL application is encountering performance issues when reading large amounts of data from a VSAM file. What optimization techniques can you apply to improve performance?
- Apply caching mechanisms to reduce disk I/O
- Implement parallel processing for data retrieval
- Increase buffer size in COBOL I/O statements
- Use indexed file organization for faster access
To improve performance when reading large amounts of data from a VSAM file, applying caching mechanisms to reduce disk I/O is effective. Caching stores frequently accessed data in memory, minimizing the need for repeated disk reads and enhancing overall application speed.