1. What is Swift?
a) A programming language
b) A design pattern
c) A framework
d) An operating system
Answer: a) A programming language
2. Which of the following is true about Swift's type safety?
a) Swift is not type-safe
b) Swift allows implicit type conversion
c) Swift ensures that variables are always of the correct type
d) Swift only supports dynamic typing
Answer: c) Swift ensures that variables are always of the correct type
3. Who developed Swift?
a) Google
b) Apple
c) Microsoft
d) Facebook
Answer: b) Apple
4. What is a typealias in Swift?
a) A way to create an alias for a method
b) A way to create an alias for a type
c) A way to create an alias for a class
d) A way to define a protocol
Answer: b) A way to create an alias for a type
5. What is a computed property in Swift?
a) A property that is only accessible within the defining class
b) A property that holds its value using a getter and setter
c) A property that is automatically initialized
d) A property that is read-only
Answer: b) A property that holds its value using a getter and setter
6. Which Swift operator is used for creating a range?
a) ..
b) ...
c) :
d) ;
Answer: a) ..
7. What is the main advantage of using Swift over Objective-C for iOS development?
a) Better performance
b) Easier integration with C and C++ code
c) Stronger type safety
d) More mature ecosystem
Answer: c) Stronger type safety
8. Which Swift control flow statement is used for multi-way branching?
a) if
b) switch
c) while
d) for
Answer: b) switch
9. What does the 'as?' keyword do in Swift?
a) Forces downcasting to a specified type
b) Attempts downcasting to a specified type, returning an optional
c) Checks if a value conforms to a protocol
d) Creates an instance of a class
Answer: b) Attempts downcasting to a specified type, returning an optional
10. What is a playground in Xcode used for?
a) Creating a user interface
b) Writing and testing Swift code
c) Debugging the code
d) Deploying the application
Answer: b) Writing and testing Swift code
11. What is the purpose of the 'guard' statement in Swift?
a) To define a new variable
b) To exit early if a condition isn't met
c) To handle exceptions
d) To execute a block of code repeatedly
Answer: b) To exit early if a condition isn't met
12. What is optional binding in Swift?
a) A way to unwrap optional values safely
b) A way to declare a variable as optional
c) A type of loop in Swift
d) A method to handle exceptions
Answer: a) A way to unwrap optional values safely
13. Which of the following is a correct way to create an empty array in Swift?
a) let myArray = []
b) let myArray = Array()
c) let myArray: [Int] = []
d) All of the above
Answer: d) All of the above
14. Which keyword is used to declare a constant in Swift?
a) var
b) let
c) const
d) final
Answer: b) let
15. What is a guard statement in Swift?
a) A way to declare a new variable
b) A way to conditionally execute code and unwrap optionals
c) A way to define a class
d) A way to handle errors
Answer: b) A way to conditionally execute code and unwrap optionals
16. What is the purpose of the 'inout' parameter in Swift?
a) To pass a parameter by reference
b) To declare a parameter as optional
c) To specify the access control of a parameter
d) To handle exceptions
Answer: a) To pass a parameter by reference
17. Which Swift operator is used for string concatenation?
a) +
b) -
c) *
d) /
Answer: a) +
18. What is a closure in Swift?
a) A block of code that can be passed around and executed
b) A variable that can hold multiple values
c) A predefined function in Swift
d) A way to define a class in Swift
Answer: a) A block of code that can be passed around and executed
19. Which Swift collection type is ordered and can contain duplicate values?
a) Set
b) Array
c) Dictionary
d) Tuple
Answer: b) Array
20. What is the purpose of the 'lazy' keyword in Swift?
a) To defer property initialization until it's accessed
b) To declare a variable as read-only
c) To mark a property as optional
d) To specify the access control of a property
Answer: a) To defer property initialization until it's accessed
21. Which of the following is true about Swift's automatic reference counting (ARC)?
a) It prevents memory leaks
b) It only applies to classes
c) It's a garbage collection mechanism
d) It's disabled by default in Swift
Answer: a) It prevents memory leaks
22. What does the 'self' keyword represent in Swift?
a) The current instance of a class
b) The superclass of a class
c) The current module
d) The main application thread
Answer: a) The current instance of a class
23. What is the purpose of the 'break' statement in Swift?
a) To exit a loop early
b) To skip the current iteration of a loop
c) To resume execution from a specific label
d) To terminate the program
Answer: a) To exit a loop early
24. Which of the following is not a standard data type in Swift?
a) String
b) Double
c) Decimal
d) Int
Answer: c) Decimal
25. Which Swift access control keyword restricts access to the current source file?
a) public
b) internal
c) fileprivate
d) private
Answer: c) fileprivate
26. What is a protocol in Swift?
a) A design pattern
b) A set of methods and properties that a conforming type must implement
c) A way to define a class hierarchy
d) A method to handle exceptions
Answer: b) A set of methods and properties that a conforming type must implement
27. What is the purpose of the 'defer' statement in Swift?
a) To execute a block of code only if a condition is met
b) To define a new variable
c) To execute a block of code when exiting the current scope
d) To pause the execution of a program
Answer: c) To execute a block of code when exiting the current scope
28. What is type inference in Swift?
a) The process of assigning a specific type to a variable
b) The ability to deduce the type of an expression during compilation
c) The process of converting one type to another
d) The ability to declare a variable without specifying its type
Answer: b) The ability to deduce the type of an expression during compilation
29. Which Swift operator is used for forced unwrapping of an optional?
a) ?
b) !
c) :
d) %
Answer: b) !
30. What is an enum in Swift?
a) A design pattern
b) A way to define a class hierarchy
c) A type that defines a group of related values
d) A method to handle exceptions
Answer: c) A type that defines a group of related values
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