iOS interview Questions swift and Answer : Part 3

Technical swift interview Question and Answer for iOS developer: Part 3

Table of Contents

iOS interview Questions swift and Answer for experience and fresher candidate

iOS interview questions swift for experience student for preparation of job interview

1 .What is ARC (Automatic Reference Count ) ?

ARC ( Automatic Reference Count ) is the used to manage and track the memory in iOS Application . It Automatically manage the application memory and release the class memory when it is no longer needed.

2.What is difference between Foundation and Core Foundation?

Core Foundation

is the C-level API, which provides CFString, CFDictionary and the like.

Foundation

is Objective-C, which provides NSString, NSDictionary, etc.

3.How many states are there in iOS life cycle?

Not running
Active
Inactive
Suspended
Background

4. In Which thread does Api gets called?

In background Thread Api services gets call

Ex URLSession.shared.dataTask

5. What is singleton class in swift ?

SingleTon class is the object which provide single point of access to the function of the class

example: 
Class Common  { 
static let shared = Common()
 private init()      
func sum()-> Int { 
     return 10 + 20   
   }
 }

accessing the singleton

let Sum = Common.shared.sum() 
print (Sum)

output Sum = 30

6.What are the difference between Cocoa and Cocoa Touch ?

FrameWork

Cocoa is the combination of Foundation and Appkit
Cocoa touch is the combination of Foundation and UIKit

OS

Cocoa is basically related to MAC OS
Cocoa touch is related to all the Devices of the Apple

API

Cocoa: All the classes used in Cocoa have the NS prefix Ex: NSTextField
Cocoa Touch: classes used in Cocoa have the UI prefix Ex: UITextField

7. What is the use of reuseIdentifier in swift ?

ReuseIdentifier is used to group the cell of the UItableview.

8. What are the Different types of DisPatchQueue?

Main , concurrency and Serial

9. What is KV0 ?

KVO(Key value observer) is used to detect the changes in property or value.

10 . What is Lazy Property in swift ?

A lazy stored property is a property whose initial value is not calculated until the first time it is used. You indicate a lazy stored property by writing the lazy modifier before its declaration. iOS interview Question and Answer : Part 3 for more iOS interview Questions swift and Answer

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