Abstract classes vs. interfaces

[juanferman]

I just face up this question and I want to check with you guys what is the right answer...

What is the difference beetwing Abstract classes vs. interfaces and a simple sample.

Thanks



===================
: Juan F. Sarria

 

[haslo]

You can define functions in an abstract class, but you can only define what functions are there in an interface. You can implement several interfaces in a class, but you can only extend one other class, be it abstract or not. That's about it

Interfaces are a way to tell a class what it has to implement and define ... its interface to the outside world (what a surprise), while abstract classes are a way to implement part of a classe's behavior, while leaving out several crucial and function-defining parts, therefore crippling the class so it can't be used unless those crucial parts are defined by an extending class.

I hope that was somewhat clear...

public interface MyInterface
{
  public abstract void doSomething();
  public abstract void doSomethingElse();
}

public abstract class MyAbstractClass
{
  public void doSomething()
  {
    doSomethingElse();
  }
  public abstract void doSomethingElse();
}

haslo@haslo.ch - www.haslo.ch​

 

[juanferman]

Thanks a lot haslo

===================
: Juan F. Sarria