iOS Interview Questions And Answers Part11

1.What is the difference between the "copy" & "mutableCopy"?

Answer:-
copy returns an immutable (can't be modified) copy of the array.

mutableCopy returns a mutable (can be modified) copy of the array.

Copy (in both cases) means that you get a new array "populated" with object references to the original array (i.e. the same (original) objects are referenced in the copies.

If you add new objects to the mutableCopy, then they are unique to the mutableCopy.

​If you remove objects from the mutableCopy, they are removed from the original array

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2.What is the difference between the "Synchronous" & " Asynchronous "?
Answer:-

Synchronous :
synchronous communication refers to interaction happening in real-time – a meeting or phone conference.

Asynchronous:
Asynchronous communication happens anytime and doesn’t rely on being together at the same time – in person or electronically.  E-mail is a good example of asynchronous communication.

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3.What is the Nib File: 
Answer:-

Nib files play an important role in the creation of applications in OS X and iOS. 

With nib files, you create and manipulate your user interfaces graphically, using Xcode, instead of programmatically. 

Because you can see the results of your changes instantly, you can experiment with different layouts and configurations very quickly.

 You can also change many aspects of your user interface later without rewriting any code.

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What is UIApplication?
Answer:-

The UIApplication class provides a centralized point of control and coordination for applications running on IOS.
 
Every application must have exactly one instance of UIApplication (or a subclass of UIApplication). 

When an application is launched, the UIApplicationMain function is called; among its other tasks, this function creates a singleton UIApplication object. 

Thereafter you can access this object by invoking the sharedApplication class method.

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5.What is Framework?
Answer:-

Framework is a hierarchical directory that encapsulates shared resources, such as a dynamic shared library, nib files, image files, localized strings, header files, and reference documentation in a single package.

Multiple applications can use all of these resources simultaneously.

The system loads them into memory as needed and shares the one copy of the resource among all applications whenever possible.

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6.What is Foundation Framework:?
Answer:-

The Foundation framework defines a base layer of Objective-C classes. In addition to providing a set of useful primitive object classes, it introduces several paradigms that define functionality not covered by the Objective-C language.

The Foundation framework includes the root object class, classes representing basic data types such as strings and byte arrays, collection classes for storing other objects, classes representing system information such as dates, and classes representing communication ports.

Example:
NSString, NSNumber, NSArray, NSMutableArray, NSDictionary, NSMutableDictionary, NSSet, NSMutableSet, NSData, NSMutableData, NSDate, etc.

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