TOP 10 iOS Interview Questions at 2022 — Part2

1. What are the JSONSerialization rendering options?

Arrays and dictionaries are constructed as variable objects rather than constants. In the JSON object graph, leaf strings are produced as instances of variable strings. allowFragments: The parser should be able to handle top-level objects that aren’t arrays or dictionaries.

2. What is the reuseIdentifier’s purpose? What is the benefit of setting it to something other than zero?

In a UITableView, the reuseIdentifier is used to group together comparable rows; that is, rows that differ only in content but have similar design.

In most cases, a UITableView will only allocate enough UITableViewCell instances to display the table’s visible content. If reuseIdentifier is set to a non-nil value, UITableView will try to reuse an already allocated UITableViewCell with the same reuseIdentifier when the table view is scrolled. If no reuseIdentifier is specified, the UITableView will be required to allocate new UITableViewCell instances for each new item that scrolls into view, perhaps resulting in stuttering animations.

3. What are the differences between “strong” and “weak” references? Why are they significant, and how can they be utilized to manage memory and prevent memory leaks?

Any variable that points to another object has a “strong” reference by default. When two or more items have reciprocal strong references, a retain cycle arises (i.e., strong references to each other). ARC (iOS’ Automatic Reference Counting) will never destroy such items. Even if every other object in the application relinquishes ownership of these objects, the mutual strong references will ensure that these objects (and any objects that reference them) continue to exist. As a result, there is a memory leak.

Strong reciprocal references between things should be avoided as much as feasible. Weak references, on the other hand, can be used to avoid memory leaks when they are required. Declaring one of the two references weak breaks the retain cycle, preventing the memory leak.

Consider the objects in the retain cycle to be parents and children for deciding which of the two references should be weak. The parent should have a strong reference (i.e., ownership of) its child in this connection, but the child should not have a strong reference (i.e., ownership of) its parent.

For example, if you have Employer and Employee objects that reference one other, you’ll probably want to keep the Employer’s reference to the Employee object strong but the Employee’s reference to the Employer weak.

What exactly is an iOS developer, and what are his duties? An iOS developer is a programmer or software engineer who creates apps for Apple’s iOS operating system on iOS devices. The iOS developer should ideally be proficient in two programming languages: Objective-C and Swift.

4.What exactly is an iOS developer, and what are his duties?

An iOS developer is a programmer or software engineer who creates apps for Apple’s iOS operating system on iOS devices. The iOS developer should ideally be proficient in two programming languages: Objective-C and Swift.

An iOS Developer’s Primary Responsibilities

1. Coding for iOS applications that is clean and efficient.
2. Continuously exploring, assessing, and integrating new technologies to improve development efficiency.
3. The creation and deployment of complex software features, as well as the upkeep and enhancement of current features.
4. Assisting with the design, testing, release, and support of applications.
5. Develop unique solutions to fulfill customers’ business demands.
6. Perform troubleshooting and bug fixes for applications to ensure clean and secure code.

5. In terms of game development, what do you mean by the SpriteKit and SceneKit frameworks?

SpriteKit: This toolkit is designed to enable creating animated 2D assets/objects in casual games easier and faster for game developers. It allows you to create two-dimensional drawings of shapes, particles, text, photos, and movies.

SceneKit is an iOS framework derived from OS X that aids in the creation of 3D visuals. You can create 3D animated sceneries and effects for your iOS games and apps using SceneKit.

6. What framework is used to create the user interface of an iOS application?

UIKit is built particularly for iOS development, unlike the Foundation framework, which includes classes, protocols, and functions for both iOS and OS X development. UIKit is used to create the application’s user interface and graphical architecture on iOS. It contains:

Event management (handle different gestures like input gestures, button-tap gestures, multi-touch gestures, etc.) App architecture (Manages the interaction between the system and user) User Experience (Provides user interactions, the ability to share text and content, select images, edit videos, print files, etc.) Graphic design, illustration, and printing

7. What are generics?

Any type can take this type. It is type safe, which means that the compiler will raise an error during compilation. A compile-time error arises if you supply a string as a generic type and use it as an integer. This is advantageous since you may detect mistakes before they occur.

8. How would you explain delegates to a new Swift developer?

Delegation allows you to have one object act in place of another, such as your view controller acting as a table’s data source. Because the delegate pattern is so widespread in iOS, choose a tiny, particular example, like UITableViewDelegate from UIKit, that you can examine from memory.

9. When using arrays, what’s the difference between map() and compactMap()?

Remember to offer examples as well as a summary of the main differences. So, map() alters a series using a function we specify, but compactMap() does the same thing but unwraps its optionals and discards any nil values. Because producing an Int from a String is failable, compactMap() is superior for transforming an array of strings into integers.

10. What experience do you have of functional programming?

Of course, providing extensive descriptions of what you’ve used and where you’ve used it is the ideal answer, but make sure to discuss what functional programming entails — functions must be first-class types, you emphasize pure functions, and so on.

If you’re not sure where to begin, the simplest response is to describe some minor details: if you’ve used map(), compactMap(), flatMap(), reduce(), filter(), and other similar functions, that’s a good place to start.

Good luck to you at interview :)

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