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.
What is parameter passing in subprograms, and why is it important?
- Parameter passing is a mechanism to pass data between programs and is important for sharing information
- Parameter passing is not supported in COBOL
- Parameter passing is only applicable to procedures, not functions
- Parameter passing refers to the allocation of storage for variables in a subprogram
Parameter passing in subprograms involves transferring data between the calling program and the called subprogram. It allows the subprogram to receive input values, process them, and potentially return results to the calling program. This mechanism enhances code modularity and facilitates code reuse.
In a COBOL "IF" statement, what happens if the condition is not met?
- An error is generated
- The "ELSE" statement is executed
- The control transfers to the next statement outside the "IF" block
- The program terminates abruptly
If the condition in a COBOL "IF" statement is not met, the control transfers to the next statement outside the "IF" block. If an "ELSE" statement is present, it will be executed; otherwise, the program continues with the next statement.
In COBOL, the _______ statement is used to perform a series of statements repeatedly.
- ITERATE
- LOOP
- PERFORM
- REPEAT
The PERFORM statement in COBOL is used to create loops, allowing a series of statements to be executed repeatedly. It provides various clauses for controlling the loop, such as UNTIL, WITH TEST BEFORE, and WITH TEST AFTER.
In the context of COBOL file handling, what is "read-ahead" and how does it contribute to performance improvement?
- It reads multiple records in advance to reduce I/O wait time
- It reads records from the end of the file first
- It reads records sequentially for faster processing
- It skips unnecessary records during reading
"Read-ahead" in COBOL involves reading multiple records in advance and buffering them in memory, reducing I/O wait time and enhancing performance by minimizing the need for repeated disk access.
In a COBOL program, what is the primary use of the VARYING clause within a PERFORM loop?
- To control the flow of execution in nested loops
- To define variables with varying data types
- To execute the loop only if a condition is met
- To iterate over a range of values for a loop variable
The VARYING clause in a PERFORM loop is used to iterate over a range of values for a loop variable, allowing the repeated execution of a block of code with different values during each iteration.
In COBOL, what is the purpose of the ACCESS MODE clause when working with relative files?
- DYNAMIC
- KEY
- RANDOM
- SEQUENTIAL
The ACCESS MODE clause in COBOL specifies how records in a relative file are accessed. RANDOM allows direct access to records based on the record number. This is useful when individual records need to be retrieved without the need to read sequentially through the file.
When working with COBOL structures, the POINTER clause is used to indicate the ___________ of the current element within the structure.
- Address
- Index
- Position
- Size
In COBOL, the POINTER clause is used to indicate the memory address of the current element within the structure. It allows for dynamic memory manipulation and is often used in conjunction with the USAGE IS POINTER clause.