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Now as we start using objects and their attributes and methods more and more,

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we're going to start to see why it is that they are so useful and so loved by

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programmers. Now,

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I think one of the non-programmers that explained OOP the best is actually the late

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Steve Jobs.

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And he has this brilliant example that makes it really clear why objects are so

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great. In his story

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he talks about this concept where let's say you were traveling to Japan and

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after a long flight,

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you finally land and you go outside and there's beautiful cherry blossoms, Mt.

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Fuji is looking wonderful. But unfortunately on the flight,

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you had soiled your T-shirt.

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You were overly eager with the tomato juice and you spilled everything upon

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yourself. So what do we do? Well,

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you're in this unfamiliar city and you have no idea

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even whether the hell you are let alone where to find the nearest

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dry cleaners or launderette. And plus on top of that,

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you don't have the local currency. They take yen,

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but you only have pounds and you don't even speak Japanese. So what do you do?

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It's going to be a real struggle trying to solve this problem. Well,

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you staying at a hotel, right? And the hotel staff probably speak English.

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So you go the receptionist and you tell it the hotel that, Hey,

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my t-shirt is soiled and they say, Hey, no problems. We'll take that from you.

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And we'll go and handle all of that messy stuff.

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We know how to find the dry cleaners,

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we can pay them in the local currency and we speak the local language.

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And what you get back is just a nice clean t-shirt.

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So this is similar to the process of working with objects. Essentially,

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if you have this hotel object

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which has a blueprint for how to handle dry cleaning

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some sort of clothing, then all you have to do is just get the object hotel and

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then call its associated method dry clean,

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and then it will do all of the messy stuff for you.

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And you don't have to worry about the implementation of this function at all.

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So now you can work with multiple objects

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getting them to do different things and trust that they know how to manage their

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data and how to perform the necessary functionality.

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Coming back to a problem that we've already solved

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creating that coffee machine with all of the program requirements. Well,

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it's time to put our Object Oriented Programming knowledge to the test because

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we're going to be making a OOP version of our coffee machine.

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Now the program still has the same requirements

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as before. You have to print reports for

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all the resources, you have to check if the resources are sufficient,

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process coins, check transaction is successful, and finally make coffee.

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But in this case, you're going to be working with objects.

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In the course resources,

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you'll find a link to the starting project for the OOP coffee machine.

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So if you head over to this link,

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you can see that there's a whole bunch of code that we've already written for

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you. Now,

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the idea here is you're not going to touch any of these other files,

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the money machine, the menu, or the coffee maker. All that code has already

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been written for you

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and it's almost like you're working with an external library.

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You're just going to trust that they do what they say they do.

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And you'll find a link to this coffee machine documentation that I've created

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which describes in detail what each of these classes or blueprints allow you to

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do. So once you construct an object from the menu item class,

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then you have access to the name attribute, the cost attribute,

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ingredient attributes, and there's also descriptions of what it should do

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and what an example might be.

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You have access to all of these classes and you can build objects from each of

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these classes to solve this project.

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In order to work with PyCharm, all you need to do is to download the zip

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file it with all the starting code from our course resource website.

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Alternatively,

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if you are already logged in on Repl.it, simply fork the project and then click

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on these three dots to download the zip file here. Now,

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once you found that in your downloads folder,

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all you have to do is uncompressed or unzip it.

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And then you can go into PyCharm and open it here.

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So click on the open button and then navigate to where you had that folder

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downloaded. Remember it needs to be unzipped.

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If you're on windows, right-click the zip file and choose extract all.

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Then click extract.

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You should see an unzipped folder popup next to your zip file.

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If you're on Mac then all you need to do is just double-click on the .zip file.

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Now, if we click open on that folder,

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then it will open up this project. And when you open up the project folder,

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you'll see all of the same files.

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Now you're only going to be working from the main.py. In fact,

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I don't even want you to care that much about the code that's in the other

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files.

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It has class definitions and a whole bunch of other things that we're going to

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learn about in the next lesson.

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But for now, I want you to treat it as if it is an external library

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which you're just going to use. At the very beginning of the main.py file,

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I've already imported all four classes that you are going to be using; menu,

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menu item, coffee maker, and money machine.

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Now all of these classes are documented in the coffee machine documentation

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website.

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All you have to do is head over to this website and read through what each of

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the classes do. Some of them have attributes and methods,

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others just have methods.

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So each of these classes have already pre-written code that do a lot of the

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heavy lifting and all of the code that we had to write when we wrote the coffee

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machine code from scratch.

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But this time you're only going to be using these four classes and the objects

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created from them in order to achieve exactly the same goals as before.

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So while the goals are fresh in your mind from the previous day,

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you should review the code from the previous day and then have a read of the

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documentation and see how you would implement exactly the same project

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but this time using only the objects created from these classes.

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You'll need to spend some time on this because you'll need to think through how

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to create objects from these blueprint classes and then how to use the objects,

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how to call the methods and the logic that's required to put everything

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together. Pause the video

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now, have a think about this problem, and try to make the coffee machine do

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exactly the same and have all the same functionality as the coffee machine that

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you created in yesterday's project.