How does inheritance work in Object-Oriented COBOL, and what benefits does it offer?
- By defining the size and type of data
- By optimizing program execution
- By organizing data in memory
- Inheritance allows a class (subclass) to inherit attributes and behaviors from another class (superclass). Benefits include code reuse, extensibility, and the ability to model relationships between classes.
In Object-Oriented COBOL, inheritance enables a subclass to inherit properties from a superclass, promoting code reuse, extensibility, and the modeling of relationships. A subclass can reuse attributes and behaviors from its superclass, leading to more maintainable code.
In COBOL, the EXIT statement is commonly used in conjunction with the _________ condition.
- EVALUATE
- IF
- NOT
- WHEN
In COBOL, the EXIT statement is commonly used in conjunction with the WHEN condition. This allows the program to exit a loop or a paragraph based on a specified condition.
Which intrinsic function is used to return the current date in COBOL?
- FUNCTION CURRENT-DATE
- FUNCTION DATE-CURRENT
- FUNCTION DATE-NOW
- FUNCTION NOW
The FUNCTION CURRENT-DATE in COBOL is used to retrieve the current date. It returns a data item containing the current date in the format YYYYMMDD.
Which COBOL data type allows you to store both numeric and alphabetic characters?
- PIC 9
- PIC A
- PIC X
- PIC X(10)
The COBOL data type PIC X(10) allows you to store both numeric and alphabetic characters in the same field. It is a flexible alphanumeric field that can accommodate a mix of characters.
How is the OCCURS clause used to define an array in COBOL?
- By indicating the start and end indices
- By setting the REDEFINES attribute
- By specifying the number of occurrences and the data type
- By using the INDEXED BY phrase
To define an array in COBOL using the OCCURS clause, you specify the number of occurrences and the data type of the array elements. This allows the compiler to allocate memory for the array and enables efficient indexing and manipulation of array elements.
How does COBOL handle multi-dimensional arrays?
- By defining separate one-dimensional arrays
- By using nested OCCURS clauses
- By using the MULTI-DIMENSIONAL keyword
- COBOL does not support multi-dimensional arrays
COBOL handles multi-dimensional arrays by using nested OCCURS clauses. This allows the creation of tables with multiple levels, providing a structured way to represent data in multiple dimensions.
When working with indexed files, which access mode is commonly used to update existing records?
- "Dynamic" access mode
- "Extend" access mode
- "Random" access mode
- "Sequential" access mode
The "Random" access mode in COBOL is commonly used when working with indexed files to update existing records. It allows direct access to any record in the file based on the key value.
In COBOL, what happens when you declare a variable in the DATA DIVISION but outside of any specific procedure?
- The variable becomes global and can be accessed by all procedures within the program
- The variable is accessible only within the procedure where it is declared
- The variable is deallocated after each procedure call
- The variable is initialized automatically
When a variable is declared in the DATA DIVISION outside of any specific procedure, it becomes global in scope. This means it can be accessed by all procedures within the program, making it available throughout the program's execution.
Why might you choose variable-length records over fixed-length records in COBOL file processing?
- To enforce strict record size consistency
- To improve processing speed in sequential file access
- To save storage space by avoiding padding unused portions
- To simplify program logic and enhance readability
Choosing variable-length records in COBOL can save storage space by avoiding the need to pad unused portions. It is especially beneficial when dealing with data of varying lengths, reducing wasted storage.
COBOL programs can optimize file handling performance by utilizing ____________ to store frequently accessed records in memory.
- Buffering
- Hashing
- Indexing
- Sorting
Buffering is a technique in COBOL where frequently accessed records are stored in memory buffers, reducing the need for frequent disk I/O operations and improving overall file handling performance. It helps in minimizing the time required to read or write records from/to external files.