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All right.
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So now that we've learned all about structures, let's go ahead and remove our functional, but slightly
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ugly bit of code here where we have our 2D quiz array, and instead let's turn it into an array of quiz
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items created from a structure. In order to create a structure,
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we're going to go ahead and make a new file. So you can either go to File, New, File... Or simply just right
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click on one of these folders where you want the file to live inside, and go to New File.
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And there, we're going to choose a new Swift file.
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So under iOS, choose a Swift file and hit Next.
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And now we're going to name our file: Question.
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Now, it's convention that we have the same file name as the name of our structure.
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So our structure is going to be called Question.
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So ideally, you want your file to also be called Question.
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Now, it's not obligatory, it's just good programming practice so that other programmers will be able to
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recognize what it is that you're doing.
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So inside this new File, we're going to create a struct with the struct keyword.
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And if I hit enter, you can see that it uses the code snippet for a struct to help me create this new
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Struct. And struct are pretty easy.
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They just have a name and some fields.
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So the name of my struct is going to be Question with a capital Q. So now that I've created my struct,
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I'm going to give it some fields. So let's delete that place holder and let's go ahead and think about
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what fields or properties would make sense to be associated with our Question.
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Well, each question really needs a bit of question text and an answer
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that's the right answer.
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So in our Question struct., I'm going to create those two fields or properties and I'm gonna create them
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using constants.
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So we have a constant code text which is gonna be of data type string and we have a constant code answer
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which is also going to be of data type string.
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Now that we've created our properties, we can go ahead and initialize it inside our ViewController.
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Right here, we're going to replace this array with a question item. To initialize a new structure, write
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the name of the structure, and then we add a pair of parentheses. And then inside here, we're going to
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go ahead and initialize some of those fields that we had, namely the question text and the answer.
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So the text is, of course, this one, and the answer is going to be true. So we're going to paste that in
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there and we can now delete our previous array.
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So now we have a question object here and we can replace these two as well. So now we have an array of
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question objects and that's reflected when we hold down option and we click on our quiz array.
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You can see it's now a collection.
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So it's square brackets. And inside the collection,
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we've got a whole bunch of Question objects. So now we've avoided the sort of ugliness of a 2D Array.
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And our quiz array is now far easier to understand.
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It's just got a whole bunch of questions, each with a text and an answer.
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So now we have to go and fix our code to use this new format. Here instead of tagging that one at the
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end,
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we're instead going to write .answer because this is going to look inside our quiz array and it's
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going to pull out the item at this particular position.
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So let's say that we put out the first one.
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So then we get a question object and we can tap into its answer property by simply writing .answer.
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Now, if you find it easier, you can actually split it into two parts. So you can say the actualQuestion
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which is equal to quiz at questionNumber.
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And this allows you to inspect on its data type which is a question data type.
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So that's that custom data type that we created.
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And then, of course, this question data type has two properties: text or answer.
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So that means if we then go ahead and write actualQuestion, then we can write a dot and we can see all
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the properties that it has, text and answer.
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So you can either do it this way or the previous way whichever way you find easier to understand.
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Now, I'm gonna keep it like this just to keep it short and sweet because I think this should be explanatory
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enough.
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So now all we have to do is to fix the last line of code inside our updateUI function.
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I'm going to leave this to you as a challenge.
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Try and fix this error using what we've just learned about accessing properties from our structures.
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Pause the video now.
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All right.
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So again, we're going to remove this second part because we used to have a 2D Array and now we don't.
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And instead, I'm going to tap into the text property to populate my questionLabel text property.
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So now if we run our code, you'll notice that absolutely nothing about the functionality or the appearance
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has changed, but our code is now structured a lot better, and we can easily extend it by creating more
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structures in the way that we have done here.
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And we have code that is now easily understandable at a glance here where we create our quiz array, as
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well as here, where we tap into the quiz questions properties.
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Now, we can actually make this code even simpler if we went into our question struct and actually created
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a custom initializer. So we can say that when we have to initialize a new question instance, instead
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of putting text an answer which is quite wordy, why don't we just have "q" which is going to be a string
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and "a:" which is going to be a string. That way when we initialize our question, we can set our text to
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equal "q" and we can set our answer to equal "a."
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Now, when we initialize our question object here, instead of having to write text and answer, all we need
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is just "q" and "a," and this way we can customize how we initialize our structures so that we write even
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less code and even more succinct code. Now that we've understood how this works, we're going to go ahead
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and actually delete all of these questions that we've created in order to learn about structures, and
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instead, I want you to go into themREADME file and scroll down to the section where it says Default
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Quiz. I want you to copy all the questions that are currently inside that section and then we're going
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to paste it inside our quiz array. So to save you from typing a million lines, we've created all of these
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questions for you in the structure of the question that we have created.
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So now if you run the app, you'll see that we now have a working quiz with 12 question items.