Swift Questions and Answers for Viva

Answer-1: The defer statement schedules a block of code to be executed at the end of the current scope.

Answer-2: Lazy properties are initialized only when accessed for the first time.

Answer-3: @IBOutlet connects UI elements in Interface Builder to Swift code.

Answer-4: @IBAction links user actions in Interface Builder to Swift methods.

Answer-5: Swift uses do-catch blocks to handle errors, along with try, try?, and try!.

Answer-6: try propagates errors; try? returns nil on failure; try! forces execution and crashes on failure.

Answer-7: Lazy properties are initialized once when accessed; computed properties calculate their value dynamically.

Answer-8: @escaping indicates that a closure can outlive the function it was passed to.

Answer-9: Generics allow the creation of reusable and type-safe code that works with any type.

Answer-10: mutating methods modify the instance's properties, typically in structs.

Answer-11: The final keyword prevents a class from being subclassed or a method from being overridden.

Answer-12: The Codable protocol simplifies encoding and decoding of data to and from formats like JSON.

Answer-13: DispatchQueue manages the execution of tasks in a multi-threaded environment.

Answer-14: The main queue is serial and runs on the main thread; global queues are concurrent.

Answer-15: Any represents any type, including value and reference types; AnyObject is limited to reference types.

Answer-16: @available marks APIs with availability information, such as minimum OS version requirements.

Answer-17: A keypath provides a reference to a property or value in a type, often used for dynamic lookups.

Answer-18: inout parameters allow a function to modify the original variable's value.

Answer-19: typealias provides a new name for an existing type, improving code readability.

Answer-20: Features include immutability, higher-order functions, map, filter, and reduce.

Answer-21: Optional chaining allows safe access to properties or methods of optionals, returning nil if unavailable.

Answer-22: guard is used to ensure a condition is true and exit early if it is false.

Answer-23: @objc exposes Swift code to Objective-C, enabling interoperability.

Answer-24: Swift access control levels include open, public, internal, fileprivate, and private.

Answer-25: The dynamic keyword enables runtime dispatch for properties or methods.

Answer-26: Property observers (willSet and didSet) monitor and respond to changes in a property's value.

Answer-27: Swift is a powerful, modern programming language developed by Apple for iOS, macOS, watchOS, and tvOS development.

Answer-28: Key features include type safety, optionals, closures, generics, protocols, and native error handling.

Answer-29: Type inference allows the compiler to determine the variable's type automatically based on its initial value.

Answer-30: Optionals represent a variable that can hold a value or nil and are declared using ?.

Answer-31: You can safely unwrap an optional using if let, guard let, or the nil coalescing operator (??).

Answer-32: var declares mutable variables; let declares immutable constants.

Answer-33: A tuple groups multiple values into a single compound value.

Answer-34: Closures are self-contained blocks of code that can be passed around and executed later.

Answer-35: A protocol defines a blueprint of methods, properties, and other requirements for adopting types.

Answer-36: Classes are reference types and support inheritance; structs are value types and do not support inheritance.

Answer-37: ARC (Automatic Reference Counting) is a memory management feature that tracks and manages object lifetimes.

Answer-38: Swift uses ARC to automatically deallocate objects when they are no longer referenced.

Answer-39: Strong references increase the object's retain count; weak references do not, avoiding retain cycles.

Answer-40: guard is used to exit a block early if a condition is not met, improving readability and safety.

Answer-41: An enum is a type that defines a group of related values, making them type-safe.

Answer-42: Higher-order functions are functions that take other functions as arguments or return them. Examples include map, filter, and reduce.

Answer-43: map transforms each element; flatMap transforms and flattens nested collections.

Answer-44: Extensions add functionality to existing classes, structs, enums, or protocols without subclassing.

Answer-45: A computed property calculates its value dynamically rather than storing it directly.

Answer-46: willSet is called before a property's value changes; didSet is called after it changes.

Answer-47: Escaping closures are executed after the function returns; non-escaping closures are executed within the function.

Answer-48: Protocol-oriented programming emphasizes the use of protocols to define shared behavior and achieve code reuse.

Answer-49: Synchronous tasks block execution until they complete; asynchronous tasks allow other tasks to run concurrently.

Answer-50: The Result type represents either a success with a value or a failure with an error.