Best Swift Interview Questions and Answer Preparation Resources
Ios Swift is a dialect that is extremely for secure coding since it effortlessly wipes out all untrustworthy code classes and guarantees secure coding condition to create a steady arrangement. Swift is a robust and specially dialect. It makes a compiler blunder i.e. AS when you compose an uncouth code. Besides, it likewise decreases the time and assets exhausted on bug settling. In this way lessens code length. Moreover, Swift applications are effortlessly good with the largely recent OS X Yosemite, iOS adaptations, and OS X Mavericks. Today Swift has turned out to be a standout in the middle of other stages, which is recognized by decreasing the measure of coding, required intended for monotonous articulations and sequenced administration.
Swift is a multi-paradigm, compiled time, and a general-purpose programming language developed by Apple Inc. It is used creating applications for iOS, macOS, watchOS, tvOS, and Linux. If you are looking for some good Ios swift interview questions then you must visit this link.
IOS Swift is a general-purpose, multi-paradigm, compiled programming language developed by Apple Inc. For iOS, iPadOS, macOS, watchOS, tvOS, Linux, and z/OS. Swift is designed to work with Apple's Cocoa and Cocoa Touch frameworks and the large body of existing Objective-C code written for Apple products.
A dictionary is a type of hash table, providing fast access to the entries it contains. Each entry in the table is identified using its key, which is a hashable type such as a string or number. You use that key to retrieve the corresponding value, which can be any object.
The nil-coalescing operator (a ?? b) unwraps an optional a if it contains a value, or returns a default value b if a is nil. The expression a is always of an optional type. The expression b must match the type that is stored inside a.
The nil-coalescing operator is shorthand for the code below:
The main use of guard statement in Swift is to transfer program control out of scope on certain conditions. These statements are similar to if statements that execute statements based on a certain condition (boolean value) but unlike if, the guard statements only run when certain conditions are not met.
Multiline comments in Swift start with a forward-slash followed by an asterisk (/*) and end with an asterisk followed by a forward-slash (*/). Everything in between /* and */ is ignored by the swift compiler.
Memento Pattern:- Memento pattern is a behavioral design pattern. Memento pattern is used to restore the state of an object to a previous state. As your application is progressing, you may want to save checkpoints in your application and restore back to those checkpoints later.
Adapter Pattern:- In software engineering, the adapter pattern is a software design pattern (also known as Wrapper, an alternative naming shared with the decorator pattern) that allows the interface of an existing class to be used as another interface.
Regular Expression:- A regular expression, regex or regexp is a sequence of characters that define a search pattern. Usually, such patterns are used by string searching algorithms for "find" or "find and replace" operations on strings, or for input validation.
Responder chain:- The responder chain is a series of linked responder objects. It starts with the first responder and end with the app object. If the first responder cannot handle an event, it forwards the event to the next responder in the responder chain. A responder object is an object that can respond to and handle events.
Swift language provides 'Generic' features to write flexible and reusable functions and types. Generics are used to avoid duplication and to provide abstraction. Swift 4 standard libraries are built with generics code. Swift 'Arrays' and 'Dictionary' types belong to generic collections.
Higher Order Functions in Swift (Sorted, Map, Filter, Reduce) are simply functions that operate on other functions by either taking a function as an argument or returning a function. These functions are useful for writing nice, clear, and concise code.
A delegate is a form of type-safe function pointer used by the Common Language Infrastructure (CLI). Delegates specify a method to call and optionally an object to call the method on. Delegates are used, among other things, to implement callbacks and event listeners.
Deinitialization is the process to deallocate or cleanup unused class instance objects to free a memory space occupied by the system resources for a better memory management.
A deinitializer is called immediately before a class instance is deallocated. You write deinitializers with the deinit keyword, similar to how initializers are written with the init keyword. Deinitializers are only available on class types.
Typealias in Swift is used to provide a new name for an existing data type in the program. Once you create a typealias, you can use the aliased name instead of the existing name throughout the program.
Typealias doesn't create a new data type, it simply provides a new name to the existing data type. The main objective of using typealias is to make our code clearer and human-readable.
Selectors are effectively the names of methods on an object or struct, and they are used to execute some code at runtime. They were common in Objective-C, but the earliest versions of Swift didn't include some core selector functionality so their use declined for a while.
Swift 4 offers the programmer a rich assortment of built-in as well as user-defined data types. The following types of basic data types are most frequently when declaring variables −
Int or Uint − This is used for whole numbers. More specifically, you can use Int32, Int64 to define 32 or 64 bit signed integer, whereas UInt32 or UInt64 to define 32 or 64-bit unsigned integer variables. For example, 42 and -23.
Float − This is used to represent a 32-bit floating-point number and numbers with smaller decimal points. For example, 3.14159, 0.1, and -273.158.
Double − This is used to represent a 64-bit floating-point number and used when floating-point values must be very large. For example, 3.14159, 0.1, and -273.158.
Bool − This represents a Boolean value which is either true or false.
String − This is an ordered collection of characters. For example, "Hello, World!"
Character − This is a single-character string literal. For example, "C"
Optional − This represents a variable that can hold either a value or no value.
Tuples − This is used to group multiple values in single Compound Value.