Scala Functional Programming Concepts Quiz

1. What is functional programming?

• Functional programming is a technique that emphasizes the importance of mutable data within a program.
• Functional programming is a paradigm that uses functions as the central building block of programs, striving to use pure functions and immutable values.
• Functional programming is a method that primarily focuses on using classes and objects in software design.
• Functional programming is a style where procedures are the main components of program logic.

2. What are some key concepts in functional programming?

• Key concepts include encapsulation, polymorphism, inheritance, and abstraction.
• Key concepts include immutability, referential transparency, function composition, and lazy evaluation.
• Key concepts include recursion, iteration, state mutation, and side effects.
• Key concepts include variables, constants, loops, and conditionals.

3. What is immutability in functional programming?

• Immutability means using constants that cannot change, ensuring thread safety.
• Immutability involves using mutable states to enhance performance in coding.
• Immutability is the process of deleting variables in a program, freeing memory.
• Immutability refers to making all variables dynamic, allowing frequent changes.

4. What is referential transparency in functional programming?

• Referential transparency means that the output of a function depends only on its inputs and not on any side effects or external state.
• Referential transparency means that function results are always predictable regardless of input.
• Referential transparency means that outputs can vary with random state fluctuations.
• Referential transparency means that a function can modify its input parameters directly.

5. What is pattern matching in functional programming?

• Pattern matching is a technique used to handle different cases in a program, allowing for more expressive and concise code.
• Pattern matching means assigning values to multiple variables at once.
• Pattern matching is a process of merging multiple functions into one.
• Pattern matching refers to the use of loops to iterate over data.

6. What is function composition in functional programming?

• Function composition refers to the transformation of function parameters into arrays for efficiency.
• Function composition is the method by which variables are created and used in functional programming.
• Function composition is the process of combining two or more functions to create a new function, allowing for more complex operations to be performed.
• Function composition is strictly alternative programming methodologies that simplify code organization.

7. What is lazy evaluation in functional programming?

• Lazy evaluation allows for the simultaneous execution of multiple functions in functional programming.
• Lazy evaluation is a mechanism where expressions are only evaluated when their values are actually needed, which can improve performance by delaying unnecessary computations.
• Lazy evaluation is when functions are defined but never executed, leading to static performance.
• Lazy evaluation means executing all expressions immediately to ensure all values are computed at once.

8. What are higher-order functions in Scala?

• Higher-order functions in Scala are functions that cannot accept parameters.
• Higher-order functions in Scala are functions that only return boolean values.
• Higher-order functions in Scala take other functions as parameters or return functions as output.
• Higher-order functions in Scala are functions that use only primitive data types.

9. What is the map function in Scala?

• The map function combines elements of two collections into a single collection.
• The map function generates a fixed-size array based on input parameters.
• The map function sorts a collection and removes duplicates from it.
• The map function transforms one collection into another by applying a function to each element, changing the element type but keeping the collection type.

10. What is the flatMap function in Scala?

• The flatMap function transforms data types without changing the structure of the collection.
• The flatMap function is similar to map but removes the inner grouping of an item and generates a sequence.
• The flatMap function sums all elements in a collection and returns a single value.
• The flatMap function searches for a specific element in a collection and returns its index.

11. What is the filter function in Scala?

• The filter function removes duplicates from a collection entirely.
• The filter function adds new elements into a collection.
• The filter function sorts a collection in ascending order.
• The filter function creates a new collection containing only elements that satisfy a given predicate.

12. What is the reduce function in Scala?

• The reduce function performs a sort operation on the elements of a collection.
• The reduce function maps each element of a collection to a new collection type.
• The reduce function filters elements from a collection based on a condition.
• The reduce function applies a binary operator to all elements in a collection, reducing them to a single value.

13. How does Scala enforce immutability?

• Scala enforces immutability by allowing only primitive data types to be mutable, keeping complex types constant.
• Scala enforces immutability by making all collections mutable, which prevents unintended data changes.
• Scala enforces immutability by making variables immutable by default, requiring the use of mutable collections like ArrayBuffer for mutable state.
• Scala enforces immutability by using mutable variables for all data types, which allows easy state changes.

14. What is the main entry point of a Scala program?

• run() procedure
• main() method
• execute() command
• start() function

15. How do you create a single-line comment in Scala?

• #
• /* */
• //
• —

16. What is the default value of a string variable in Scala?

• Null
• “
• Undefined
• None

17. What is the subtype of all types in Scala?

• Nothing
• Something
• Everything
• Anything

18. What is returned by a function with no return value in Scala?

• Unit
• None
• Null
• Nothing

19. Can you return two values from a function in Scala?

• Yes, you can return two values from a function in Scala using Options.
• No, you can only return one value from a function.
• No, Scala does not support multiple return values.
• Yes, but only with mutable variables.

20. How do you define a higher-order function in Scala?

• You define a higher-order function in Scala by implementing a class that inherits from a base function type.
• You define a higher-order function in Scala by creating a variable that stores the function`s return value.
• You define a higher-order function in Scala by using recursion to call the same function repeatedly.
• You define a higher-order function in Scala by taking another function as a parameter or returning a function as output, as seen in the example with map.

21. What is the range defined by the statement range(13, 17, 2)?

• 14, 16
• 12, 18
• 15, 17
• 13, 15

22. Which method is not used for printing text on the screen in Scala?

• print()
• printf()
• println()
• printl()

23. What is the output of the code val i = 43; i = 231; printf(i)?

• 231
• Undefined
• Error, as the val keyword defines immutable values in Scala.
• 43

24. What are literals in Scala?

• Literals are methods that modify variables
• Literals are classes that store data types
• Literals are functions that calculate values
• Literals are values that can be assigned to a variable

25. Which conversion is lossy or invalid?