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Now, if you're just learning to code, you've seen this word class and you've probably wondered, what



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does it mean?



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Well, it's a way of grouping stuff logically.



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So if we had a class that represented a dog, we could put some variables in it.



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Let legs equals four because dogs have four legs and let tail equals true because they have tails.



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We can also have a function called Wolf, which prints out Wolf for us.



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So what this class does is illogically arrange all of the properties that a dog has and all of the functions



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that a dog has.



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Classes are the fundamental structure that we use to organize our code.



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So you might have something like a class to fetch a Eurail from your observer.



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You'll have a class to share something via Facebook.



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You'll have classes to do all of these things.



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And in fact, well, I'm not going to say that's a class because I don't think it is, but it is I think.



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Ignore me on that.



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I have to explore that a bit more anyway.



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Class dog is.



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A blueprint, right, a blueprint doesn't exist.



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Yes, I know you can see the code, but it doesn't actually exist yet as an object because blueprints



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make objects, classes make objects.



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So when you hear the word object in programming, it's because someone went to a class called Doug open



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and close some brackets.



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Now it's an object.



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Now the dog is real.



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Left froglet dog equal to dog.



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OK, so now that I have that object, I can start making it do whatever I want.



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I would like you to, Wolf.



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And so when I hit play, that is going to print out Wolf for us.



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OK, so a class is a fundamental way of organizing things.



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Now, what if I had a cat?



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So I'm just going to copy the first part of my notes here.



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And this cat is like the dog, it has legs, a tail, it has a name and it has meow.



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Now legs and tails always stays like that, basically.



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Cat's always meow, right, but what about this name?



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How do we fill that in?



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Because every cat has a different name.



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What we can use is the Init function.



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Now in it is a special function that gets called whenever the class creates something from itself,



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whenever this blueprint turns into a cat object.



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The in it allows you to pass arguments over just like any other function, and then once you've passed



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the argument over, you can do stuff with it so you can say set self-taught name self simply refers



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to the current object of this cat.



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And we the reason we use it is because we have a name here and a name here, and we need to distinguish



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which one we're talking about.



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So this one refers to that.



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And this one refers to that, right, so we're setting the name of this object to the name we've passed



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in and so we can have our cat is equal to Cat.



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And you'll notice this gives an error because it says I need to have a name for the in it parameter.



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So we say, fine, you may have Felix.



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Now, when we hit play, we get our cat called Felix, how do we know he's called Felix?



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But we can say cat dot name.



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And there we have Felix passed in, so this in it actually is short for initialise.



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It's the thing that creates the object from the class, if you like.



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The thing that kicks it all off well, it doesn't kick it off, does something further down the chain.



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But we don't need to worry about those specifics right now.



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So I've got some homework for you with classes.



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And here it is, create a class for an accounts package, account software.



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I want you to have two variables.



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One store's income, one store's expenses, just integers.



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Create two functions that add the expense variable and the other one to add to the income variable.



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OK, this is the first part of the homework we're going to carry on with this class concept.



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So that's probably not that difficult.



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Go ahead and give that a go.