IOS Interview Questions & Material

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 tell the compiler instantly by using synthize directive. Actually this tells to compiler generate a getter&setter message.

Q3. What  is non atomic?

Ans: To avoid conflict the multithreading.

Q4. What  is retain?

Ans: It is reference count of the object.

Q5. 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.

Q6. What  is parsing?

Ans: To access the data in the XML element is called parsing.

Q7.Which class  we  can  use  for  passing  of xml  in  iphone?

Ans: By “NSXML” Parser.

Q8. Which  type of  parse  we  have  use  in  iphone?

Ans:”SAX” parser.

Q9. Which  class are used to establish  connection  b/w application to webserver?

Ans:  (a)NSURL

         (b)NSURL REQUEST


Q10. 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.

Q11. 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 element

          (c)found character.

Q12. 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.

Q13. 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.

Q14. By  default application which  things  contain?

Ans: In ipone applications by default having 3 things

1.mainIt is entry point of application.

2.AppdelegateIt is perform the basic application & functionality.

3.WindowIt  is provide uiinterface.

Q15. What is  uiviewcontroller?

Ans:   uiview controller is base class for all the controller

Q16. 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 methods  

         (a) push view

         (b) pop view

      By default navigation controller contain “table view”.

Q17. What is tab bar controller?

 Ans: Tab bar is used to common way to display the data on iphone.

Q18. 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

Q19. 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


Q20. By default table view which controller contain?

Ans: Detail view controller that is present is ui table view delegate

Q21.  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.

Q22. What are data base are used in iphone?

Ans:              (a). Sql lite 

          (b). Plist

          (c). Xml

Q23. 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.

Q24. 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

Q25. 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.

Q26. 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

Q27. 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.

Q28. 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.

Q29. 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

          1.  implemented through use of the @property and @synthesized.

Q30. 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]

 Q31. 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.

Q32. What is single inheritance in objective-c?

Ans: Objective-c subclass can only be derived from a single direct parent class this concept is called as “single inheritance”.

Q33. Ns object is parent class or derived class?

Ans: Ns object is parent class and contains a number of instance variables and instance methods.

Q34. How to call function in objective-c?

Ans:   [account display account info]

           Account-> object name

           Display account info-> method name


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