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

1. 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)

2. 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

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

nil

void

none

empty

4. 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

5. 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

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

function myFunction() { }

def myFunction() { }

func myFunction() { }

sub myFunction() { }

7. 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 }

8. 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?

9. 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

10. 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 { }

11. 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

12. 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

13. 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

14. 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

15. 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

16. What are closures in Swift?

A way to represent a sequence of values in Swift

A mechanism for capturing and storing references to variables and constants

A feature for defining custom attributes in Swift

A set of predefined functions in Swift for handling errors

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

Collects user input

Formats text

Displays output in the console

Defines a variable

18. 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

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, 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

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

string1 <> string2

string1 != string2

string1 ~= string2

string1 .notEqual(string2)

22. Which Swift data type is used to store decimal numbers?

Int

Double

Float

Decimal

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

let

var

const

static

24. 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

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. 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 { }

27. 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

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

var myArray: [Int]

array myArray = []

let myArray = [Int]

emptyArray myArray: Int[]

29. 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

30. 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

Swift MCQ Test 3