iOS Question part-4

1) what is the diff b/w object based programming and object Oriented programming Language?

-If the programming methodology supports encapsulation,Inheritance and polymorphism then, it is called Object Oriented programming language, it supports code extendability.
-If the programming methodology supports only encapsulation then, it is called Object based programming language, it supports code extendability.

2) what are the fundamental concepts of oops?

3) what is encapsulation and its Advantage?
Grouping related thing together is called Encapsulation, we can acheive Portabily.

4) How to implement the encapsulation in c#?
By using class,struct,properties,interface etc.

5) What is DataHiding ?
Hiding unnecessary details from the user.

6) What is the Advantage of DataHiding ?
Due to DataHiding behavior of the product can be protected, so that developers logic can be secured.

7) What is Abstraction ?
Hiding complete implementation details from the user is called abstraction.
due to abstraction user will feel comfortable while working with the product.

8) Diff b/w DataHiding and Abstraction ?
DataHiding : Hiding unnecessary data from the user,programmer is benifited.
Abstraction : Hiding complete implementation details from the user,User is benifited.

9) What is class ?
Class is a collection of related data and relevant objects.

10) What is an Object ?
An instance of the class.

11) What is the diff b/w Encapsulation and class ?
Encapsulation: Is a object oriented programming concept.
Class: it is a feature of the language by which we can implement encapsulation.

12) What is the default access modifier for the class?

13) What is the default access modifier for the members of the class?

14) What is the default access modifier for the members of the struct?

15) Diff b/w Class and Struct ?

Class Struct
1. Class is Object type 1. Struct is value type
2. All accessmodifiers are allowed. 2. Protected is not supported
3. Inheritance is possible. 3. Not possible.
4. Supports all types of constructors. 4. Default Constructor is not supported.
5. Distructor allowed. 5. Not allowed.
6. method overriding possible. 6. Not possible.

16) What is Accessor Method and Mutator method ?
Accessor Method:
Any of the method is defined to access the value from the instance variable.
Mutator Method:
Any of the method is defined to modify the value from the instance variable.

17) what is the use of base Keyword ?
To access the base class members in the derived class we can use base keyword.
To invoke the base class constructor from the derived calss constructor.

18) What is the diff b/w property and indexer ?
If we use property we can get and modify the values from the instance variables .
By using indexer we can access the object by applying subscript with index position.

19) What is Constructor ?
Constructor is a special method in the class, which is used to initialize the instance variables to some meaning full initial values, when the class is instantiated.

20) Why the name of Constructor and class is same ?
For easy identification purpose of the compiler.

          Objective C interview questions

Q1.What is property?
Ans:Properties are used to access the instance variables from outside of class.
Q2. What is synthesized?
Ans:After you declare the property in objective-c . we have to tell the compiler instantly by using synthesize directive. Actually this tells to compiler to generate a getter&setter message.
Q3. What is retaining?
Ans:It is reference count of the object
Q4. What are the accesses specifies?
Protected (by default protected)
Q5. Is there over loading function in object c?
No not there
Q6. Instance method followed by………………………
Member variable
Q7. Instance method begins with?
Q8. Class method begins with?
Q9. @interface
Methods define
Q10. @implementation
Define methods are implemented
Q11. Default constructor syntax is?
– (id) init.

Q12. What is data encapsulation?
Ans: Data is contained with in objects and is not accessible by any other than
via methods defined on the class is called data encapsulation.
Q13. What is accessor methods?
Ans: Accessor methods are methods belonging to a class that allow to get and set
the values of instance valuables contained with in the class.
Q14. What is synthesized accessor methods?
Ans: Objective-c provides a mechanism that automates the creation of accessor
methods that are called synthesized accessor methods that are
implemented through use of the @property and @synthesized.
Q15. How to access the encapsulated data in objective-c?
Ans:(a)Data encapsulation encourages the use of methods to +get and set the values
of instance variables in a class.
(b)But the developer to want to directly access an instance variable with out having to go through an accessor method. (c) In objective-c syntax for an instance variable is as follow [class instance variable name]
Q16. What is dot notation?
Ans: Dot notation features introduced into version 2.0 of objective-c
Dot notation involves accessing an instance variable by specifying
a class “instance” followed by a “dot” followed in turn by the name of instance variable or property to be accessed.
Q17. What is single inheritance in objective-c?
Ans: Objective-c subclass can only be derived from a single direct parent class this s concept is called as “single inheritance”.
Q18. Ns object is parent class or derived class?
Ans: Ns object is parent class and contains a number of instance variables and instance methods.

Q19. What is the instance methods?
Ans: Instance methods are essentially code routines that perform tasks so instances
of clases we create methods to get and set the instance variables and to display
the current values of these variables.
Declaration of instance method :
– (void)click me: (id)sender;
Void is return type which does not giving any thing here.
Click me is method name.
Id is data type which returns any type of object.
Q20. What is the class method?
Ans: Class methods work at the class level and are common to all instance of a
class these methods are specific to the class overall as opposed to working
on different instance data encapsulated in each class instance.
@interface class name :ns object
+(class name *)new alloc:
-(int)total open 

                  Iphone/Ipad Interview FAQ’s

1. What is delegate? The helper object is called the delegate.
2. What is protocol? Types off protocols?
List of methods that share among the class.
Types of protocols
Formal protocols are those protocols that are implemented using Objective protocols:
@protocol NSFoo <NSSomeProtocol>
-(int) doesIt;
Informal protocols are defined as categories on NSObject with no implementation:
@interface NSObject(FooDelegate)
– (void)optionalFooDelegateMethod;
3. What are categories?
Categories allow you to add functionality to already existing classes without extending them.

4. What is the difference b/w iphone and ipad?
Size is bigger than I phone. Split view application is added in ipad.
5. How to customize u r app in iphone?
Winterboard is an application that let you customize your iPhone / iPod 2.0+.
6. What is the Winterboard?
Winterboard allows you to customize Springboard of your iphone. Using Winterboard you can change iPhone icons, customize applications, status bar graphics, iPhone dock graphics, install themes and change wallpapers of your iPhone Springboard. You can even customize sounds on your iPhone. With Winterboard you can theme almost everything that comes to your mind. Before iPhone 2.0 there was Summerboard but Winterboard has replaced it since iPhone 2.0 and can even load themes of Summerboard.
7. What is the springboard?
Springboard is the standard application that manages the iOS (formerly iPhone OS) home screen.
8. What is the difference between retain and copy?
Retain: this retains the new value in your setter method
This makes a copy of the string in your setter method
9. What is the memory management?
It allocates and reallocates memory and find out memory leaks.
10. What is the singleton?
Singletons are a class that only gets instantiated once in your application’s run-time.
11. How many layers are there in iphone sdk?
.cocoa touch layer
Address book UI
.media layer
.audio toolbox
.audio unit
.AV foundation
.core Audio
.core graphics
.media player
.open GL ES
.quartz Core
.core service layer
.address book
.core foundation
.core location
.system Configuration
.core os layer
.CF network
12. What is the IB?
It design app user interface graphically save those are resource file that u load into application at run time.
13. What is the difference between retain and release?
Retain: Increment index by 1
Release: decrement index by 1
14. What the difference b/w loadview and viewdidload?
When you load your view from a NIB and want to perform further customization after launch, use viewDidLoad.
If you want to create your view programmatically (not using Interface Builder), use loadView.
15. What are the methods we are using in table view?
.number of sections in table view
.number of rows in section
.cell for row at index path
.did select row at index path
16.Tell me about json-parser?
Ans:”JSON” Means “Java script object notation”.
It is a one type of parser (or)test-based and hightweight parser.
17.By default application which things contain?
Ans:In ipone applications by default having 3 things
1.main→It is entry point of application.
2.Appdelegate→It is perform the basic application & functionality.
3.Window→It is provide uiinterface.
18.What is uiviewcontroller?
Ans: uiview controller is base class for all the controller.
19. What is the navigation controller?
Ans: Navigation controller contains the stack of controllers every navigation controller
must be having root view controller by default these controllers contain 2 method 
(a) push view (b) pop view
By default navigation controller contain “table view”.
20. What is tab bar controller?
Ans: Tab bar is used to common way to display the data on iphone.
21. What is the table view controller?
Ans: Table view controller contains the number of rows and columns visible in the
application and makes a cell editable or not as a response to key press
22. Which protocols are did used in table view? Ans: Table view contain 2 delegate protocols
(a). Ui table view data source
(b). Ui table view delegate.
In ui view table view data source contain these methods
(a). No of sections.
(b). No of rows in sections.
(c). Cell for row index path row.
In ui table view delegate contain these methods
(a). Did select row at index path row
23. By default table view which controller contain?
Ans: Detail view controller that is present is ui table view delegate.
24. What is the split view controller?
Ans: This control is used for ipad application and it contain proper controllers by default
split view controller contain root view controller and detail view controller.
25. What are data base are used in iphone?
Ans: (a). Sql lite (b). Plist c). Xml (d). core data
26. Tell me about the MVC architecture?
Ans: M-model, V-view, C-controller
Main advantage of MVC architecture is to provide “reusability and security”
by separating the layer by using MVC architecture.
Model: it is a class model is interact with database.
Controller: controller is used for by getting the data from model and controls the views.
Viewdisplay the information in views.
27. What are frame works are used in iphone?
Ans: (a). Ui kit framework
(b). Map kit framework
(c). ADI kit framework
(d). Core data framework
(e).core foundation framework
28. What is webservice?
Ans:Main purpose is to expose the data in form of xml format ,by using this we can getting the  data from server.
29. What is parsing?
Ans:To access the data in the xml element is called parsing.
30.Which class we can use for passing of xml in iphone?
Ans:By “NSXML” Parser.
31.Which type of parse we have use in iphone?
Ans:”SAX” parser.
32.Which class are used to establish connection b/w application to webserver?
33.What is difference between DOM&SAX?
Ans:(a)Dom is a documents based parser.
When we will work with these parser all the data of xml is stored in RAM. In this parser “memory consumption” is more.
(b)SAX is a event driven parser.When we will work with these parser,take only reference from  xml file and generate the oneevent for every element.
34.After parsing if you want to get your data in view which delegation methods are did you use?
Ans:(a)did start element (b)did end elemen (c)found character.
35.How many methods are used in NSURLConnection?
Ans:I have 4 types methods
(a)Connection did receive Response
(b)Connection did recevice Datat
(c)Connection fail with error
(d)Connection did finish loading.
36. What is the difference b/w NSString and NSMutableString?
NSString the length is fixed can’t append another string
NSMutableString It can append another string
37. Where the programs start execution?
A) Application Did Finish lunchingwithOption
38. Which API’s are using in u r application?
A) API means frameworks like UIkit, foundation, Core animation
39. What is the cocoa?
Object c frame work called COOCA. The specific part of the framework used for iPhone app development is called Cocoa Touch .
40.What is the difference Between APPKit and UIKit?
A)there is NO APPKit in iphone and there is no UIKit in Mac OS



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