Do We Inherit a Interface or Implements an Interface?

Question

Well till now I knew we implement interfaces , but today some body (you know who , i guess)) told me that If I write a interface then we implement it in class , but if it is a system Interface , Let's say INotifyPropertyChanged , the we call it Class A inherits Interface INotifyPropertyChanged.

Though I feel right , I am not sure and unsure how to explain it to him.

I need to specify in my Design doucment . So wondering what shall I mention, Inherit or Implemet.

Part of the confusion stems from c++ lacking `interface` that is distinct from `class`. Users of Java will be able to point out their differences. — rwong, Oct 14 '10 at 07:56
This is really a C# question, but as other have said you implement an interface. This is done by inheriting from it. — Daniel Lidström, Oct 14 '10 at 08:06
helpful question I found is here http://stackoverflow.com/q/8531292/1055241 — gprathour, Jan 27 '12 at 07:21

score 5 · Answer 1 · answered Oct 14 '10 at 07:32

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We inherit it to implement it. What's the problem?

answered Oct 14 '10 at 07:32

Yakov Galka

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I need to specify in my Design doucment . So wondering what shall I mention, Inherit or Implemet. – Oct 14 '10 at 07:40
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@user443144: implementing. Inheritance is a detail of implementation. – Yakov Galka Oct 14 '10 at 07:43

score 1 · Answer 2 · answered Oct 14 '10 at 07:33

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1-Interface is implemented by a class whether is it a normal interface or system interface.

2- One Interface can inherit another interface.

answered Oct 14 '10 at 07:33

TalentTuner

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score 1 · Answer 3 · answered Oct 14 '10 at 07:56

Speaking language-independant you would say "implementing an interface". The symbol in UML names it the same (there is a special implementing-arrow which is used for interfaces instead of the inheriting-arrow)
Anybody understanding UML would understand what you're meaning.

In C++ you have to consider that there aren't interfaces as they exist in other languages. A interface is a pure virtual class. So classes which "use" this interface are strictly speaking inheriting from a pure virtual class. If you're saying "MyClass inherits the pure virtual class IClass" someone C++-related would understand that you mean interface I think. He also would understand if you say "MyClass is implementing IClass" and in background think of a pure virtual class.

score 0 · Answer 4 · answered Oct 14 '10 at 07:59

If Class A provides the method bodies (that is, code) for the methods that are declared in the interface, then Class A is implementing the interface.

In C++, because of the lack of distinction between interface and class, the source code syntax for inheriting from a class and implementing an interface is the same. Hence the confusion.

Do We Inherit a Interface or Implements an Interface?

4 Answers4