what is a design patterns?

Question

hai everyone. Recently i was faced a telephonic round regarding ios developers.

The questions they were asked is

1.what are design patterns in ios?

2.what is a static class?

3.what is plist?

4.when you used abstraction in real time application?

5.what is child class ?

6.when inheritance is used in real time application?

7.when static is used in real time?

 

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 personal doubt:

Actually i said design patterns means mvc to the interviewer, but interviewer was not satisfied with my answer.so,can you any one please suggest the exact meaning of design patterns in ios.