1. Abstract classes &
Interfaces
Programming in C#
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2. Abstract Classes

3. Abstract Classes
referred to as an incomplete base class
cannot be instantiated, can only be sub-classed.

4. Implementation
The subclass inheriting the abstract class has to override and
implement the abstract methods
https://gist.github.com/2373593

5. Inheritance

6. Purpose
A subclass in C# cannot inherit two or more base class.

7. Interfaces
contains only abstract members
cannot implement any methods
cannot be instantiated
by default, all members have public as the access modifier
cannot contain constants, data fields, constructors, destructor and
static members

8. Implemetation
https://gist.github.com/e63d1cf32b03cd888686

9. Mutiple Inheritance
https://gist.github.com/7856dad9ccfe58aaa0da

10. Interface Inheritance
An interface can inherit multiple interfaces but cannot implement
them.
https://gist.github.com/2374963

11. What difference between abstract classes & Interfaces?

12. Short
Interface: contract only, no implementation, no instantiation
Abstract class: contract, some implementation, no instantiation
Interface specifying what
the object can do
Abstract specify what an object is

13. Similarities
cannot be instantiated
are implemented by the inheriting subclass
can inherit multiple interfaces

14. Differences

15. Some stories

17. Recommendations

18. Multiple version of component => Abstract class
functionality will be useful across a wide range of disparate objects
=> Interfaces
small, concise function bits of functionality => Interfaces
common, implemented functionality among all implementations of
your component => Abstract class