Explain the concept of abstract classes in Object-Oriented COBOL.
- Abstract classes are only used for file operations.
- Abstract classes are those with no attributes.
- Abstract classes are used for basic arithmetic operations.
- Abstract classes cannot be instantiated and may have abstract methods.
In Object-Oriented COBOL, an abstract class is a class that cannot be instantiated on its own and may have abstract methods (methods without implementation). Abstract classes serve as a blueprint for other classes, providing common attributes and methods that subclasses must implement. They allow for code reusability and the definition of common behavior across multiple classes.
A table in COBOL can be defined with the OCCURS _____ ON clause to allow dynamic sizing.
- DEPENDING
- INDEX
- SIZE
- TIMES
In COBOL, the OCCURS clause is used to define tables. The OCCURS SIZE clause allows dynamic sizing of the table based on the specified size.
What is the difference between "ON SIZE ERROR" and "AT SIZE ERROR" in error handling?
- "AT SIZE ERROR" handles file-related errors
- "ON SIZE ERROR" handles arithmetic operations that result in a data overflow condition
- "ON SIZE ERROR" is used for index-related errors
- Both are identical and can be used interchangeably
"ON SIZE ERROR" in COBOL is specifically used to handle arithmetic operations that result in a data overflow condition. On the other hand, "AT SIZE ERROR" is used for file-related errors. Understanding this difference is crucial for effective error handling in COBOL programs.
Why are COBOL group data items used in program design?
- To enhance data manipulation efficiency
- To improve program readability
- To organize and structure related data items
- To reduce memory usage
COBOL group data items are used to organize and structure related data items, improving program readability and maintenance. They also contribute to efficient data manipulation by grouping logically related elements together.
Which division of a COBOL program is responsible for defining external files?
- FILE SECTION
- INPUT-OUTPUT SECTION
- LINKAGE SECTION
- WORKING-STORAGE SECTION
The "FILE SECTION" in COBOL is responsible for defining external files that the program will read from or write to. It specifies the organization, access mode, and other attributes of the files used by the program.
In COBOL, the INDEXED BY phrase is used to create a(n) ____________.
- Alias for a variable
- Alternate entry point
- Index for a table
- Subroutine
The INDEXED BY phrase in COBOL is used to create an index for a table. It allows you to reference individual occurrences in a table using an index variable.
In a COBOL program for an inventory system, you need to calculate the total cost of goods sold (COGS) for a batch of products. Which arithmetic operation should be applied to achieve this?
- ADD
- COMPUTE
- DIVIDE
- SUBTRACT
To calculate the COGS, you should use the SUBTRACT operation to subtract the cost of goods sold from the initial inventory. ADD, DIVIDE, and COMPUTE are not suitable for this specific calculation.
When debugging, what does it mean if you encounter a "run-time error" in your COBOL program?
- A logical error in the program's algorithm
- A syntax error detected by the compiler
- An error in the program's input data
- An error that occurs during program execution
A "run-time error" in COBOL indicates an error that occurs during program execution rather than during compilation. These errors can include issues such as invalid arithmetic operations, division by zero, or accessing memory beyond the program's allocated space. Identifying and fixing run-time errors is crucial for ensuring program correctness.
In COBOL, a _____ variable is one that is accessible throughout the entire program.
- COMMON
- GLOBAL
- PERMANENT
- UNIVERSAL
In COBOL, a GLOBAL variable is one that is accessible throughout the entire program, making it available for use in any section or paragraph.
Which COBOL data type is appropriate for representing fixed-point decimal numbers?
- PIC 9(5)V9(2)
- PIC S9(5)V9(2)
- PIC S9(5)V9(2) COMP
- PIC S9(5)V9(2) COMP-3
The data type PIC S9(5)V9(2) COMP-3 in COBOL is used to represent fixed-point decimal numbers. The COMP-3, or packed decimal, format is suitable for efficient storage of decimal data, with each digit represented by half a byte.