1
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So now did we know about these powerful features an obvious question is why would we use that.

2
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Why why is that helpful.

3
00:00:09,670 --> 00:00:15,820
Well it is useful in situations like this where we know we want to have a certain set of functionalities

4
00:00:15,850 --> 00:00:22,900
let's say agreat method and we want to ensure that a class has such agreed method and a number of class

5
00:00:22,900 --> 00:00:24,490
has it maybe as well.

6
00:00:24,490 --> 00:00:29,470
Well then we can implement an interface which forces the existence of this method.

7
00:00:29,470 --> 00:00:35,560
So then we can easily share functionality amongst classes and every class has to add its own implementation

8
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the exact code that should execute when the method is called.

9
00:00:39,460 --> 00:00:44,920
But we enforce a certain structure with the help of interfaces and this can be useful if we then have

10
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other parts of our code which rely on that structure.

11
00:00:48,730 --> 00:00:55,420
Here we said user 1 to be of type readable and with Dad we say we don't care what's inside user but

12
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what has to be in there is agreed method and we know that it has to be in there because whatever we

13
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store in user one has to be readable.

14
00:01:03,400 --> 00:01:08,950
And that allows us to write truly powerful and flexible code where we don't have to know everything

15
00:01:08,950 --> 00:01:14,500
about an object or everything about a class but we just know whatever I'm getting here and user one

16
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has to have a great method.

17
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We don't care whether a person has anything else here.

18
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We're interested in great hands who sent us to readable and therefore we can't store anything in user

19
00:01:24,760 --> 00:01:31,540
1 which would not have agreed method because readable force says whatever you base on it to have such

20
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a read method.