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OOPs Difference FAQS


This provides a list of OOPs FAQs which are of "Difference between" kind

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									1) What are the differences between TypeOf() and GetType()?

  S.N   TypeOf()                           GetType()
  1     Its an operator                    Its a method
  2     Can't be overloaded                Has lot of overloads

2) What are the differences between const and readonly?

  S.N   const                              readonly
  1     It cannot be static                It can be instance level or static
  2     It is evaluated at design time     It is evaluated at run time
  3     It is initialized at declaration   It is initialized at declaration and in
  4     It must be of integral type or     In addition, it can have complex
        enumeration                        types with new keyword and
                                           enumerations are not allowed

3) What are the Differences between Abstract Class and Interface?

  S.N   Abstract Class                     Interface
  1     It can have implemented            It cannot have implemented
        Methods                            Methods
  2     A class can inherit only one       A Class can implement any number
        abstract class                     of Interfaces
  3     We go for Abstract classes on      We go for Interface on such
        such situations where we need      situations where we need to give
        to give common functionality for   common functionality for group of
        group of related classes           un-related classes
  4     If we add a new method, then       If we add a new method, then we
        we can provide a default           need to change all the existing work
        implementation and so no need
        to make any change to existing
  5     Static and Instance constants      Only Static constants are possible
        are possible

4) What are the differences between Structure and Class?

  S.N   Structure                          Class
  1     It is value type                   It is reference type
  2     It is stored on stack              It is stored on heap
   3    It does not support inheritance It supports inheritance
   4    It is suitable for small data   It is suitable for complex data
        structure                       structures
5) What are the differences between property and indexer?

   S.N   Property                         Indexer
   1     A property can be static         An indexer is always an instant
         member                           member
   2     The get accessor of a property   The get accessor of an indexer
         corresponds to a method with     corresponds to the same formal
         no parameters                    parameter lists as the indexer

6) What are the differences between overloading and overriding?

   S.N   Overloading                      Overriding
   1    Same name in same / derived        We need to provide different
        class but with different / type of implementation than base class
   2    Has different signature            Has same signature
   3    Otherwise called Compile-time      Otherwise called Run-time
        Polymorphism                       Polymorphism
7) What is the difference between Write() and WriteLine() methods?

   S.N   Write()                          WriteLine()
   1     Write() method outputs one or    WriteLine() method outputs one or
         more values to the screen        more values to the screen with a
         without a newline character      newline character

8) What is the difference between Read() and ReadLine() methods?

   S.N   Read()                           ReadLine()
   1     Read() method returns a single   ReadLine() method returns a string
         character as int                 containing a line of text

9) What is the difference between ref and out parameters?

   S.N   Ref parameter                    Out parameter
   1     An argument passed to a ref      An argument passed to an output
         parameter must be first          parameter does not need to be
         initialized                      explicitly initialized
10)     What are the differences between Value Types and Reference

  S.N   Value Types                        Reference Types
  1     It is stored on stack              It is stored on heap
  2     It can be accessed directly        It can be accessed through
  3     Life time of value type is         Lifetime of reference type is
        determined by lifetime of          managed by .net framework
        variable that contain them
  4     Examples: All numeric data         Examples: All arrays, String, Class
        type, Boolean, char, Date,         types, Delegate
        Structure, enumerations

  Note: Object is not any kind of type. You can create object of structure as
  well as Class

  Are not type: Namespaces, Modules, Events, properties, procedures,
  variables, constants, & fields.

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