Refined Swift Test - 72+ MCQs: Swift Programming Language Quiz: Test Your Swift Skills

1. In Swift, what is the purpose of the 'subscript' keyword?

To define a subscript operator for accessing elements in a collection

To create a new subscript type

To define a function with variable parameters

To perform bitwise subtraction

2. What are the benefits of using Swift's 'struct'?

Automatic memory management

Inheritance and polymorphism

Value semantics and performance benefits

Dynamic method dispatch

3. What is the 'escaping' keyword used for in Swift?

To indicate a closure parameter that outlives the function it's passed to

To create an escaping type

To escape from a loop

To escape from an optional

4. What is the correct syntax for an 'if-else' statement in Swift?

if condition { } else { }

if { } else { }

if (condition) { } else { }

if-else condition { }

5. What is the purpose of Swift's 'defer' statement?

To declare a Swift function

To postpone the execution of a block of code until the end of the current scope

To implement error handling in Swift

To create a global constant in Swift

6. Which Swift keyword is used to check multiple conditions in an 'if' statement?

and

multiif

else

7. In Swift, how do you create an empty array of integers?

var myArray: [Int]

array myArray = []

let myArray = [Int]

emptyArray myArray: Int[]

8. In Swift, how do you define a constant with a specific data type?

let myConstant: String

const myConstant = String

constant myConstant: String

let myConstant = String

9. What is the correct way to create a range of numbers from 1 to 5 in Swift?

1...5

1..<6

range(1, 6)

range(1...5)

10. What is the purpose of the 'extension' keyword in Swift?

To extend the size of a data type

To add new functionality to an existing type

To create a new class

To override a base class method

11. What is the purpose of the 'break' statement in a loop?

To exit the program

To skip the next iteration

To end the loop prematurely

To start a new loop

12. How does Swift handle optionals and unwrapping?

Optionals in Swift are automatically unwrapped

By using the 'try' keyword

Through forced unwrapping using '!'

Swift does not have optionals

13. What is the purpose of the Swift 'enum' type?

To define a set of related values

To declare a constant in Swift

To represent a single value

Swift does not have an 'enum' type

14. How is 'protocol-oriented programming' emphasized in Swift?

By using only classes

By focusing on protocols for building types

By avoiding protocols altogether

By using only functions

15. Explain the use of Swift's 'lazy' keyword.

To define variables that cannot be modified

To create computed properties in Swift

To delay the initialization of a property until it is accessed

To restrict access to a Swift property

16. Explain the concept of Swift's 'Set' type.

A way to represent a collection of unique, unordered values

A mechanism for defining custom attributes in Swift

A feature for writing concurrent code in Swift

Swift does not have a 'Set' type

17. Which Swift keyword is used to start a loop?

start

loop

begin

for

18. What is a 'computed property' in Swift?

A property that is calculated using a function

A property that can only be set once

A property with a fixed value

A property that stores computed values

19. In Swift, what is a closure?

A block of code that can be passed around and executed

A mechanism to handle errors

A method for code encapsulation

A class that represents an abstract data type

20. What is the purpose of the 'guard' statement in Swift?

To declare a constant

To create a loop

To check for nil and else execute the code

To define a function

21. What is the purpose of the 'if' statement in Swift?

To create a loop

To define a function

To make decisions based on conditions

To import external libraries

22. In Swift, how do you use a closure to sort an array of integers in ascending order?

array.sort { $1 > $0 }

array.sort { $0 < $1 }

array.sort { $0 > $1 }

array.sort { $1 < $0 }

23. What is the purpose of Swift's 'Any' and 'AnyObject' types?

To represent any value in Swift

To declare a constant in Swift

To define a new Swift type

Swift does not have 'Any' and 'AnyObject' types

24. Which keyword is used to declare a constant in Swift?

let

var

const

static

25. How can you achieve multithreading in Swift?

By using global variables

Swift does not support multithreading

Through the use of DispatchQueue

By defining multiple classes

26. What is the 'nil coalescing operator' (??) used for in Swift?

To unwrap optionals

To force unwrap optionals

To provide a default value for optionals

To create optional chaining

27. What is the purpose of the 'map' function in Swift?

To filter elements in an array

To transform each element in an array using a provided closure

To sort elements in an array

To concatenate arrays

28. Which Swift keyword is used for creating a loop?

for

loop

repeat

cycle

29. What are the benefits of using Swift Optionals?

Reducing the need for unwrapping

Avoiding runtime crashes due to nil values

Improving code clarity and safety

All of the above

30. What is the purpose of the 'enum' keyword in Swift?

To define a class

To represent an enumeration

To create a function

To declare a protocol

31. How can you achieve thread safety in Swift?

By using global variables

By defining multiple classes

Through the use of locks and queues

Swift does not support thread safety

32. How do you declare a property as 'weak' in Swift?

weak var myProperty: Type?

myProperty weak Type?

let myProperty: weak Type?

var myProperty: weak Type?

33. What does the 'print' function do in Swift?

Collects user input

Formats text

Displays output in the console

Defines a variable

34. What are generics in Swift?

A mechanism for defining custom operators

A feature for writing concurrent code in Swift

A way to write code that can work with any type

A set of predefined mathematical functions in Swift

35. How can you define a default parameter value in a Swift function?

func myFunction(parameter: Type = defaultValue) { }

func myFunction(parameter: Type) { parameter = defaultValue }

func myFunction(parameter: Type) { defaultValue = parameter }

func myFunction(parameter: Type, defaultValue) { }

36. In Swift, how do you create a comment that spans multiple lines?

// This is a comment

# This is a comment

/* This is a comment */

' This is a comment

37. Which Swift keyword is used to indicate the absence of a value?

nil

void

none

empty

38. What is the purpose of Swift's 'extension'?

To add new functionality to an existing class, structure, enumeration, or protocol

To create a new Swift file

To define a block of Swift code to be executed later

To declare a new type in Swift

39. In Swift, what is the purpose of the 'defer' statement?

To immediately execute a block of code

To postpone the execution of a block of code until the end of the current scope

To conditionally execute a block of code

To loop over a block of code

40. Which Swift data type is used to store whole numbers?

Double

Int

Float

String

41. In Swift, how do you handle errors using the 'try', 'catch', and 'throw' keywords?

try { } catch { } throw { }

throw { } try { } catch { }

try { } throw { } catch { }

catch { } try { } throw { }

42. How can you handle errors in Swift?

By using global variables

By defining multiple classes

Through the use of the 'try', 'catch', and 'throw' keywords

Swift does not support error handling

43. In Swift, what is a 'closure'?

A function with a fixed set of parameters

A block of code that can be passed around and called

A type of error handling mechanism

A function with optional parameters

44. Explain the concept of Swift's 'inout' parameter.

A parameter indicating input in Swift functions

A keyword for defining class inheritance in Swift

A way to pass a value by reference to a function in Swift

Swift does not have an 'inout' parameter

45. What is the purpose of the 'for-in' loop in Swift?

To repeat a block of code a specific number of times

To iterate over elements in an array

To create an infinite loop

To make decisions based on conditions

46. Which collection type in Swift is unordered and does not allow duplicate elements?

Array

Set

Dictionary

Tuple

47. Explain Swift's 'associatedtype' in protocols.

A keyword for defining Swift functions in protocols

A mechanism for specifying the type of an associated value in Swift

An alternative syntax for defining Swift properties

A way to declare global constants in Swift

48. Explain the concept of protocol-oriented programming in Swift.

A paradigm emphasizing composition through protocols

A method for writing Swift protocols

An approach to writing procedural Swift code

A way to organize Swift classes hierarchically

49. Explain Swift's 'map', 'filter', and 'reduce' functions.

Predefined mathematical functions in Swift

Functions for handling errors in Swift

Functions for working with arrays, providing transformations, filtering, and combining elements

Syntax sugar for defining Swift properties

50. What is the purpose of the 'associatedtype' keyword in Swift protocols?

To specify a default implementation

To declare a typealias within a protocol

To enforce a required initializer

To associate a type with a protocol

Swift MCQ Test 1