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

1. 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

2. In Swift, how do you declare a custom error type conforming to 'Error' protocol?

class MyError: Error { }

typealias MyError = Error

error MyError: Error { }

protocol MyError: Error { }

3. 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

4. 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

5. Explain the concept of 'typealias' in Swift.

A way to create a new Swift type

A method for defining custom operators

A mechanism for specifying the type for a variable in Swift

An alternative syntax for defining Swift functions

6. 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

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

nil

void

none

empty

8. 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

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

start

loop

begin

for

10. What is the correct way to check if two strings are not equal in Swift?

string1 <> string2

string1 != string2

string1 ~= string2

string1 .notEqual(string2)

11. 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

12. 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) { }

13. 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)

14. 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

15. How does Swift handle memory management?

Swift relies on manual memory management

Swift uses automatic reference counting (ARC)

Swift requires explicit deallocation

Swift uses garbage collection

16. How does Swift handle memory management for reference types?

Through automatic reference counting (ARC)

By using garbage collection

Memory management is the responsibility of the developer

Swift doesn't support reference types

17. 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

18. In Swift, what does the 'lazy' keyword indicate when used before a property?

The property can be accessed from multiple threads

The property is initialized only when first accessed

The property is immutable

The property is marked for deallocation

19. What is the correct way to concatenate two strings in Swift?

string1 + string2

string1 .concat(string2)

concatenate(string1, string2)

string1 .append(string2)

20. 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

21. What is the correct syntax for declaring a function in Swift?

function myFunction() { }

def myFunction() { }

func myFunction() { }

sub myFunction() { }

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

let

var

const

static

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

Double

Int

Float

String

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

and

multiif

else

25. 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

26. 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

27. 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

28. 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

29. In Swift, how do you declare a variable without assigning a value?

let myVariable

var myVariable = null

var myVariable: String

let myVariable = undefined

30. 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?

31. 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

32. What is the purpose of the 'return' keyword in a Swift function?

To print a value

To exit the program

To indicate the end of a loop

To send a value back from a function

33. 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

34. What is the purpose of the 'unowned' keyword in Swift?

To declare a constant

To define an unwrapped optional

To prevent strong reference cycles

To enforce immutability

35. What is the purpose of Swift's 'subscript'?

To declare a Swift function

To implement error handling in Swift

To provide a shortcut for accessing the elements of a collection

To create a guardrail in Swift code

36. 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

37. 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

38. 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

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

Automatic memory management

Inheritance and polymorphism

Value semantics and performance benefits

Dynamic method dispatch

40. 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 2