What is the role of interfaces in Object-Oriented COBOL, and how are they different from classes?
- Interfaces are used only for input/output operations.
- Interfaces can be instantiated like classes.
- Interfaces define common behavior, and they cannot have attributes.
- Interfaces have the same characteristics as abstract classes.
In Object-Oriented COBOL, interfaces define common behavior that can be implemented by multiple classes. Unlike classes, interfaces cannot have attributes; they only declare methods. Classes can implement multiple interfaces, enabling them to exhibit behavior from different sources. Interfaces promote a higher level of abstraction and facilitate code modularity and flexibility.
The _____ clause in COBOL is used to specify the key structure when defining a VSAM file.
- FILE-CONTROL
- KEY
- RECORD
- SELECT
In COBOL, the KEY clause is used within the FILE-CONTROL section to specify the key structure when defining a VSAM file. It defines the data item or items that make up the primary or alternate key of the file.
When using the WRITE verb in COBOL, what happens if the file is not open in OUTPUT or I-O mode?
- It results in a runtime error
- The WRITE operation is ignored
- The WRITE operation proceeds, and the file is automatically opened in OUTPUT mode
- The compiler generates an error
If the file is not open in OUTPUT or I-O mode when using the WRITE verb, the compiler generates an error. It is essential to ensure that the file is opened in an appropriate mode before performing WRITE operations.
Your COBOL program must handle different status codes for customer orders. Which COBOL feature would help you define condition names for these status codes?
- CONDITION
- LEVEL NUMBER
- OCCURS
- VALUE OF
The CONDITION name is used in COBOL to represent a condition that can be tested during program execution. It allows you to define symbolic names for specific values, like status codes for customer orders, making the code more readable and maintainable.
You are writing a COBOL program to calculate the total cost of items in a shopping cart. Which type of COBOL variable would you use to store the individual item prices?
- PIC 9(3) DISPLAY
- PIC 9(5)V99 COMP-3
- PIC S9(4) USAGE COMP
- PIC X(10)
For storing monetary values like individual item prices in a COBOL program, PIC 9(5)V99 COMP-3 is suitable. This usage efficiently represents decimal numbers and ensures accurate calculations.
The CONTINUE statement is often used in COBOL error handling to ___________ the program's normal flow.
- Bypass
- Interrupt
- Maintain
- Resume
The CONTINUE statement in COBOL is used to resume the program's normal flow after error handling. It allows the program to continue executing subsequent statements in the same scope.
What is the purpose of the OCCURS DEPENDING ON clause in COBOL tables?
- It allows the number of occurrences for the table to be determined dynamically at runtime
- It defines the maximum number of occurrences for the table
- It indicates that the table is part of a nested structure
- It specifies the initial values for the table elements
The OCCURS DEPENDING ON clause in COBOL tables allows the number of occurrences for the table to be determined dynamically at runtime based on the value of a preceding data item. It provides flexibility in handling varying amounts of data.
When working with relative files, what is the significance of the RELATIVE KEY clause?
- It defines the data type of the relative key
- It establishes the relationship between the record and its relative key
- It indicates the starting point for sequential processing
- It specifies the physical location of the file on the storage device
The RELATIVE KEY clause in COBOL relative files establishes the relationship between the record and its relative key. It defines which field in the record serves as the relative key, allowing for direct access based on the relative record number.
Your COBOL program processes financial transactions, and you need to calculate the balance after a series of deposits and withdrawals. Which arithmetic statement is suitable for this scenario?
- ADD
- COMPUTE
- MULTIPLY
- SUBTRACT
To calculate the balance after deposits and withdrawals, you should use the SUBTRACT operation to deduct withdrawals from the total balance. COMPUTE, ADD, and MULTIPLY are not appropriate for this specific calculation.
In COBOL, what is the scope of a local variable declared within a procedure?
- Accessible globally across all programs
- Accessible only to other procedures in the same file
- Available throughout the program
- Limited to the procedure in which it is declared
A local variable in COBOL is limited to the procedure in which it is declared. It cannot be accessed outside that procedure, providing encapsulation and avoiding naming conflicts.