Interface vs Abstract

Interface vs Abstract

	Interface	Abstract
1	Interface cannot be instantiated	Same as Interface
2	Inteface cannot contain concrete methods. But still there is no need to declare those methods as ‘abstract’ as in Abstract classes.	Abstract can have both Concrete & Abstract methods. An ABSTRACT function does not have any implementation, and it must be overridden in any non-abstract derived class, using OVERRIDE keyword.   Note : C# does not support the “= 0” syntax to declare abstract functions.   Note: If there is any function is abstract in a class, then that class has to be declared as ABSTRACT.     e.g. abstract class AbstractPent {    public abstract string Show();   }   class AmericanPent : AbstractPent { public override string Show() {  return this.GetType().Name; }                         }
3	Do not support Inheritance	Supports Inheritance
4	Cannot contain Fields (Member Vairables) & Constructor. Otherwise – Methods, Properties, Events & indexers are allowed.   //Interface public interface Vehicles { string Engine          {                 get;               set; } void Accelerator(); }	Can contain anything.
5	Not allowed to specify access modifiers. By default they are public and cannot be virtual or static.	No Problems
6	An interface definition is also not allowed to contain operator overloads, though that’s not because there is any problem in principle with declaring them— there isn’t; it is because interfaces are usually intended to be public contracts, and having operator overloads would cause some incompatibility problems with other .NET languages, such as Visual Basic .NET, which do not support operator overloading.	No Problems

 

 

 

Thanks & Regards,

Arun Manglick

SMTS || Microsoft Technology Practice || Bridgestone - Tyre Link || Persistent Systems || 3023-6258

 

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