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

1. 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

2. 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

3. What is the purpose of the Swift 'guard' statement?

To declare a constant in Swift

To create a guardrail in Swift code

To define a Swift function

To enforce early exit in Swift based on a condition

4. 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

5. 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

6. 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

7. 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 { }

8. 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

9. 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

10. 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?

11. Which operator is used for equality comparison in Swift?

12. 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

13. 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

14. 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

15. 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

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

Collects user input

Formats text

Displays output in the console

Defines a variable

17. 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)

18. 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

19. 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

20. 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

21. 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

22. 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

23. How does Swift handle multiple return values from a function?

Through the use of tuples

By using global variables

Swift does not support multiple return values

By defining multiple functions

24. 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

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

string1 <> string2

string1 != string2

string1 ~= string2

string1 .notEqual(string2)

26. In Swift, how do you access the first element of an array?

array[0]

array.first

firstElement(array)

array.start

27. 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 { }

28. 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

29. 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) { }

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. 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

32. 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

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

function myFunction() { }

def myFunction() { }

func myFunction() { }

sub myFunction() { }

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

if condition { } else { }

if { } else { }

if (condition) { } else { }

if-else condition { }

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

let myVariable

var myVariable = null

var myVariable: String

let myVariable = undefined

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

start

loop

begin

for

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

var myArray: [Int]

array myArray = []

let myArray = [Int]

emptyArray myArray: Int[]

38. What is the purpose of an optional in Swift?

To handle errors

To define a default value

To represent a value that may or may not be present

To declare a constant value

39. 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

40. 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

Swift MCQ Test 2