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‫Welcome back to the second link demo.

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‫In this demo we are going to prepare a bunch of stuff which we will need later on.

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‫So first of all, we are going to create two additional classes and then actually third one which will

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‫handle those two classes.

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‫So those two classes that we are going to create, they should be used to create objects of those classes

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‫and they are using universities and students.

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‫So let's create a new class in here.

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‫And yes, I know you should create classes on the right hand side.

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‫Well, you should create specific files for every single class, but I'm going to create it in here

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‫in the same file in this program, CSS file, because it's easier for you to follow along.

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‫But otherwise you should always go like this.

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‫Create new and then class, and then you should go ahead.

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‫All right, so add class and this one will be university.

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‫So every university has certain information about itself.

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‫So what should a university have?

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‫Well, let's start with an ID.

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‫So I'm going to say it has an ID and this is a get and set property, a very basic property.

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‫Then I create another property and this time like this, it's going to be a string time called name.

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‫So every university has an ID and a name, nothing too fancy.

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‫Right?

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‫And then the only thing that we have to do in here is just print something.

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‫So we're going to create a method in here which is gonna be called print, and it's going to print out

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‫details, or we could call it show info or something like that.

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‫The only thing it's going to do is write something like University zero with ID one and zero will be

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‫the name and one will be the ID.

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‫All right, so that's our university class.

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‫And now let's create a class for students.

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‫So class student.

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‫So every university has students, right?

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‫And we want you go ahead and have an ID for the students as well and ID get and set then a string called

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‫name.

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‫So every student has a name cut and set and then actually let's do it with prop double tap string and

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‫every student has a gender.

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‫And then finally we add one more property.

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‫So prop and this time it's going to be the age.

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‫So every student has a specific age.

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‫And then here there is one important thing because every student has a foreign key, because if he's

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‫not at the university, he's not a student.

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‫So let's assume that.

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‫So we need to have a foreign key.

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‫Foreign key and that will be our public int university ID.

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‫So a student belongs to a specific university ID.

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‫All right.

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‫And we finally also just print something onto the console.

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‫So public void print and it's just going to print something like.

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‫CW Double tap student

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‫zero with ID one, gender two and age three from university with the ID four.

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‫And now of course need to use all of those properties.

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‫So it's going to be name ID, gender, age and university ID.

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‫And as this is a little long, I'm going to put it on the second line like that.

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‫So this is going to be the print statement of the student class.

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‫Now, in order to manage students and universities in the linkway, we will create another class.

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‫And this additional class is going to be our university manager.

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‫So it's going to handle universities, it's going to add members to the university, so students to

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‫the university.

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‫Then it's going to show us all the male students, all the female students and those kind of things.

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‫So let's create a new class for that, and I'm going to call it Class Uni.

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‫Our city manager.

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‫And then here I want to have lists to work with.

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‫So first of all, I have a list of university, so of our university type that we had and I'm going

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‫to call that university.

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‫And then another list, public list called student, which is going to be our students.

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‫So this list is full of students, this list is full of universities.

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‫And now in a constructor, we will initialize those two lists and we will add values to them.

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‫So let's go ahead and create a constructor public university manager like that.

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‫Now, that's our constructor, right?

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‫Constructor.

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‫And in here, I want to go ahead and initialize my university.

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‫So it's going to be a new list of university

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‫and my students, which will be a new list of student.

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‫And now we can go ahead and add values to them.

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‫And I'm not going to type everything manually.

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‫I'm just going to copy and paste from the list that I've prepared.

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‫So let's assume we have two universities.

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‫One is Yale, and the other one is Beijing Tech.

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‫And then we have let's some students here, which is Carla, who's female.

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‫She's 17.

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‫Then there's Toni, he's male, he's 21.

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‫And those two, they are at Yale and then the other university.

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‫So at Beijing Tech, we have Lila, which is female, then James, who's transgender, and then we have

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‫Linda, who's female.

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‫All right.

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‫So we have three different here, three different genders.

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‫All right.

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‫So this is our university manager constructor so far.

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‫And now we can go ahead and add some methods which will actually do some link things because we haven't

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‫used link in this video yet.

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‫So let's go ahead and do that.

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‫Let's create.

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‫A method which will give us all the male students.

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‫So let's create that.

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‫And here I'm going to use I enumerable so a list of students and I'm going to call it male students.

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‫And now we use the same thing that we did in the last video.

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‫So from student in students where student gender is equal to male and finally select student.

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‫All right.

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‫So that's how we create this list.

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‫We have seen it in the last video.

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‫We check out a specific list.

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‫In this case, it's a actually list because so far we have seen that with a raise.

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‫But you can do that with lists as well.

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‫So that's pretty cool.

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‫As you can see, collections, generic list and we can do that with this link approach here as well.

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‫So now let's print that on to the console.

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‫See, W is going to be male students and then finally, let's give us all the students.

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‫So we're going to use a for each loop here for each student, which is student in male students, because

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‫as we know, our male students are of type student.

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‫So now we can go ahead and call the student dot print method.

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‫All right, now let's go ahead and use this method, because so far we have only prepared and type code

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‫and type code, and now it's time to finally run the code and see what's going on.

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‫So let's go ahead and create a university manager object.

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‫Let's call it, um, and let's initialize it straightaway, which is a university manager like that.

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‫And now I can go ahead and use, um, dot male students.

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‫So this method here and finally let's also write onto the console.

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‫So console dot read key so that our program doesn't just shut down.

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‫All right, so let's run it.

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‫And we see here male students well, we have student Toni with the idea of one gender male age 21 from

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‫university with the ID one.

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‫All right, so let's check it out.

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‫We have this one male student here, so let's copy and paste the male student just to check if there

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‫can be two.

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‫So this one will be frank.

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‫And Frank is male, but he's 22 years old and he's at the second university as well.

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‫So everyone is at Beijing University as it seems.

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‫So let's run the code again.

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‫And then we are we see both rows, so we see Frank and we see Tony.

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‫So Frank is from University one and Tony?

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‫Well, actually, Tony is from one and Frank is from two.

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‫All right.

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‫So now you see this method worked fine.

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‫Now please go ahead and create a method that does the same thing.

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‫But for women.

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‫So we're just going to print out all the female students from the different universities.

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‫All right.

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‫I hope you tried it.

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‫So I'm going to type it this time.

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‫Public void.

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‫Female Student And I need an I enumerable again, which will be of type student.

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‫So a list of students which is going to be a female student's list.

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‫And I want to check from all the students.

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‫In students.

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‫So this is, as I said before, each loop here basically.

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‫And we want to check all the students where the gender is female and we want to select those students

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‫and put them into our female students.

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‫I enumerable Now we can write that on the console, so w and female students

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‫and then we use a for each loop like that it's going to use student called student and the collection

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‫called Female Students.

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‫And now in here we're just going to use student dot print.

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‫So now let's check out the female students.

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‫So u m dot female students method.

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‫And I know that this name is not perfect.

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‫It could be something like show female students or filter by female students or filter by male students.

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‫But I'll just keep it simple here.

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‫And we are female students Carla, Layla and Linda with ad1, three and five, age 17, 19 and 22.

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‫And they are different universities, as you can see here.

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‫All right.

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‫So now you have seen how you can create a bigger list in this case.

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‫We are just using a list here with elements that we have added.

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‫So you have seen how you can do that with arrays, how we can use link.

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‫So this statement here with the race and also with lists and you can use the same thing with enumerable

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‫as with well generally list types, right?

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‫And also of course with tables and with XML.

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‫And that's something that we will see later on.

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‫So let's go ahead to the next video where we will extend our class here.

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‫So our university manager class, which will well, show us some more information because so far we

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‫only see students, male and female.

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‫But what if we want to filter it by different information or if you want to sort it, stuff like that,

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‫that's something that we will cover in the next video.

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‫So see you in the next video.