Java from Beginner to Expert | Arkadiusz Włodarczyk | Skillshare

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Taught by industry leaders & working professionals
Topics include illustration, design, photography, and more

Watch this class and thousands more

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Taught by industry leaders & working professionals
Topics include illustration, design, photography, and more

Lessons in This Class

77 Lessons (10h 57m)
    • 1. Introduction

      4:31
    • 2. What is Java?

      12:40
    • 3. 5 reasons to learn Java

      2:46
    • 4. Who am I

      1:31
    • 5. Downloading and installing IDE and JDK 13

      7:31
    • 6. Creating your first project

      4:28
    • 7. Comments

      4:28
    • 8. Basics

      7:09
    • 9. Shortcuts

      8:58
    • 10. Variables

      14:11
    • 11. Naming convetions

      6:07
    • 12. Casting

      7:13
    • 13. Arithmetic operators

      11:30
    • 14. Relational Operators

      6:44
    • 15. Logical Operators

      10:08
    • 16. Bitwise Operators

      17:59
    • 17. Conditional Statements

      5:56
    • 18. Curly Bracers

      3:40
    • 19. Switch

      5:43
    • 20. Conditional Expression

      3:30
    • 21. Arrays

      10:09
    • 22. Multidimensional Arrays

      4:53
    • 23. Loops

      8:50
    • 24. Loop for

      3:41
    • 25. Enhanced for loop

      3:56
    • 26. Loop in loop

      7:56
    • 27. Break and continue

      6:54
    • 28. Summing many values

      3:21
    • 29. Object Oriented Programming Overview

      14:12
    • 30. Constructors

      8:01
    • 31. this keyword

      3:03
    • 32. Methods

      14:33
    • 33. Overloading methods

      2:53
    • 34. Static keyword

      10:38
    • 35. Packages

      12:06
    • 36. Encapsulation

      11:54
    • 37. References

      8:35
    • 38. References passing

      5:58
    • 39. Comparing Strings

      4:06
    • 40. Bottle

      9:32
    • 41. Inheritance

      15:24
    • 42. Polymorphism

      11:55
    • 43. Protected modificator

      4:55
    • 44. Abstract classes and methods

      6:14
    • 45. Instanceof

      13:54
    • 46. Downcasting

      3:55
    • 47. Object class - equals

      11:34
    • 48. toString

      2:53
    • 49. Final keyword

      6:02
    • 50. What are interfaces?

      12:09
    • 51. sorting using interfaces

      12:35
    • 52. Nested class

      11:03
    • 53. nested practical

      13:07
    • 54. anonymous classes

      8:17
    • 55. Aggregation

      5:44
    • 56. exceptions

      17:51
    • 57. lambda

      13:32
    • 58. documentation

      13:52
    • 59. Default methods

      5:34
    • 60. What after this course

      3:02
    • 61. BONUS: generic methods

      9:47
    • 62. BONUS: Generic types

      16:03
    • 63. BONUS: wild cards

      8:03
    • 64. BONUS BASICS OF ANDROID: Downloading and installing Android Studio

      6:21
    • 65. Creating your first Android Studio project

      13:48
    • 66. How to change theme in Android Studio?

      2:16
    • 67. What is SDK, How to update Android Studio

      9:00
    • 68. AVD - emulating virtual device

      17:09
    • 69. Moving freely in Android Studio

      14:25
    • 70. What is XML and how it is related to Android apps

      11:04
    • 71. Activity and Views

      11:04
    • 72. Listeners - handling events

      11:06
    • 73. Faster button event handling

      7:09
    • 74. Layouts

      6:45
    • 75. Layout Basics - Linear Layouts

      6:13
    • 76. Linear Layout exercise

      6:13
    • 77. layout_weight - dividing your layout proportionally

      5:36
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About This Class

This Java course is designed for people who don't have any knowledge about programming. It doesn't matter if you have never written any programs or you have no idea about programming... After my course, all this will change. You will bust the myth that programming is a difficult thing only for the few!

Java is one of the most in demand & highest paying programming language.

Java's slogan is: "Write once, work everywhere."

You can use Java to create Android applications, desktop applications, games and much more.

One of the most popular games called Minecraft was created using Java.

After this course you will be able to use the advanced components of Java language.

Java is the base language for developing Android apps. You have to learn Java for Android development.

Save your precious time by buying this course. You will learn how to program in a fast and easy way!

The total length of the course is over 9 hours! You will learn theory and also gain lots of practice. During the course we will write many programs in Java.

If you have any questions regarding the topics covered in this Java course after watching videos please feel free to ask. I'm always happy to help.

Meet Your Teacher

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Arkadiusz Włodarczyk

Professional teacher

Teacher

I am the author of 27 very popular video courses about programming, web-development and math in Poland. I've also created 7 video courses in English. Over 280,000 people enrolled in my courses. I put all my heart into creation of courses. I always try to explain everything the easiest possible way. I'm sure that my courses will help you in the programming and web development adventure :)

I believe that everyone has the ability to develop software if they are taught properly. Including you. I'm going to give you the context of each new concept I teach you. After my course you will finally understand everything that you code.

I've been developing websites for over 15 years and i've been programming for over 10 years. I have enormous experience in that matter and I want to sh... See full profile

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Transcripts

1. Introduction: Hello. If you are asking yourself each time when you learn something new, why it really exists? Like, for example, why doing classes? I do. We need loops. Why they're constructed like that and so on. And so then you're in the right place because I will explain you everything. The easiest possible way from scratch. I believe that everyone has the ability to develop software. If they are a properly and it's including you, I'm going to give you the context of itching concept. I tease you, and after my cars you would finally understand everything. Did you go? I would like to present your video curse Java that does get over 60 lessons and it's overnight hours of content and it's also very well organizing to 30 sections. Head with quizzes, exercises and you might be asking now. Well, you wouldn't know after these girls what you will know semantic of job, which means meaning off words in Java. This is very important part because if you have sold basics, it will allow you to create whatever you want. You will be fluent in Java language after discovers, okay, and this is the most important part for every programmer. If you want to create your own applications in future, you understand things like the rebels operators. Conditional statements mattered. Zarate subject. Look, I will go through, For example, new features like Lambda Expressions from Java. Eight arrow handed exceptions. And you will I know lots of things about object oriented programming. And it's not like giving on annoyed because I am no reading the good to confrontation. I will give you Heene's. I would tell you why something exists. Why do we need inheritance? Why do we need interfaces? How do we use them? When should we use them and other things like that? Okay, so this is not just well next cars with somebody's reading. Take the commendation. No, I am going to give you kings. I'm going to tell you when and why you should use something. Why? Something is important for you. Okay, so this is very different course, And you might be asking yourself why should you choose my cards? Right? Here are some things that you can read about, but I would tell you also that I have enormous experience in teaching other people and I do it as you have probable rather not this a bit different way. I always explain everything from start catch, and I do not omit anything. If you do not believe me, then please go ahead and watch free preview videos. I even exist towards free videos before buying anything. I'm sure that you will be satisfied with my cars after completing you. And, well, it's really, really cheap. Comparing toward you can achieve after discovers after discussing, we have knowledge. And what is the most important ability to read Java language? You know how to read Java libraries. You can create whatever you want. You have any questions, Please feel free to ask. You can send me a message, and I will respond as fast as possible. You can ask me about programming but taking my place that I am not doing homework. But I would be happy to give you Heene's, and you might be asking yourself what you should know before this girl's well, this empty patch is suggesting that you do not need to know anything, so these can be your first language. It doesn't matter. It's for beginners. But also, if you have a program, something in Java doesn't mean that it won't be useful because I'm showing things that are rarely seen in, you know, places on the Internet. Because I'm giving you kids. I'm telling you why something really is important. If you know if you are creating your programs and you don't know exactly what to do next and you're trying to copy called from Someplace, then it's wrong. I you should create your coat on your almost time when it So it should be easy for you. And that's what I'm trying to achieve in discovers. Okay? And you are and be asking also yourself. Who is that? This all tore disc person? Well, my name is our cattle grid Atrix. As you can see, I have wars of experience in the matter. I'm also author of many video courses I love. I really laugh, teaching other people okay, there are many. Collins confined them them on my other courses on the Internet. This is almost impossible to not be satisfied with this current. If you have any questions, just ask me. That's only good lesson and have a good day 2. What is Java?: Hello, my friend. Today I will tell you what this Java will this programming language. What did you have a veto on matching what is a compiler and many other things like that? Okay, these are basis. And these lesson is very, very important in orderto understand anything in, well, any language. Not only Java. You want to understand programming, you have to watch this lesson. Okay? After these lessons, everything is gonna become clear. Okay, So what is Java? Java is a programming language that we use to talk with our computer somehow. Right? Well, you see, our computer is talking in a bit different language than we are talking, right? I'm talking the English language right now and you understand pretty well, right? But our computer likes things like that. 0101111001111111 Why? Because these are electric impulses, okay? And well, they jumped from zero to ones. And that's how computer is interpreting everything that you see right now. Okay. It interprets that sequences of 01 It will be very hard for us to write programs like that , right? 01010 and dude, me mean, I show me the pixel in the color like that. And, for example, I don't show the bottom creek on batteries. I think that claim hedging by doing things like that, Ted will be horrible. That's why we have got something with this called programming languages that are that are, you know, having Centex that is, you know, easy to understand. For us, it is not you as easy as, for example, right now, English, right? But it's gonna be easy if when we learn the rules like we learned, for example, for English, right, home, another language And what we just gonna be ableto talk? So, for example, we can ride later. Something like anti Jer be. And it means, Hey, you know, I want to save in the random access memory. So in the ram and a place for the main teacher, So it means I want to save a number somewhere, right? I want to find a place like that, and this being would mean I want to reserve something for computer. Okay, It will be, you know, well, this thing would not mean anything, because it's also only understand for understand by us, right? It needs to be also changed. 2010101 And the process of changing days in tow. 0101 It's called compilation. Okay, So programming language is something that is understand that stood by us. And But it's, you know, that syntax dicks can be easily changed into zero and once, right? Okay, so this is a programming language. And why did I put so much effort to, you know, tell you what is a programming language? Because, you know, in Java, the process of compilation is a bit different. It's very hard to understand for people new to Java, and some people do not even understand. It's after your writing with programs in Java for many years. Okay, So what's going on here? You know, normally, let's, for example, see here programming language like C plus plus right when you write a coat. Okay. So imagine here. We have got some kind of code. So we have got something like that, right? And be other things like that, or, you know, something like that in Java. Whatever. We have some kind off coat and this coat is gonna be changed. by something What is called copulation, right, So we can write it. Computation. Right. So this think ah is gonna be changed into the zero and ones, right? 010101 What? This gold is called mashing code. It's gonna be executed. Everything is okay. There is a small problem in that C plus plus solution. Because, you know, there is windows. There is really no, there was marking touch Android and other things and other platforms like that. The problem about it is that when you make that compilation, right, So we changed disc out into the zero and ones it needs to know the processor that is gonna execute there. Instructions here written in that coat. Okay. And because of it, when we compile it on, for example, windows, it's gonna, you know, be able to run only on windows, so you have to later compile it. Also on, for example, Lennox. And the problem is also that only knows you can have libraries that are, you know, for example, on windows and visa versa. So you can have own windows libraries that are no the very womb Lee knows, and then you have to write code many times. Wow, Law, this is horrible, right? If you want to support many platforms, the cool thing about Java and that's what that's why it's one off the most in demand and high Spain programming language Is that the slogan of Java is right ones and work everywhere. Why and how did they manage it? What job bomb is doing some things like that when you have got a cold, right? So we have got a cold like that. We have got the process that is gonna change this coat right into something. What this called and bite goat here. Bite coat. So it is something like between death code that would have got here and that we have got here. 0101 right. Dead bite coat is not gonna be, you know, useful for us humans because, well, we cannot read it, but it is very nicely reading coat that is gonna be interpreted by something. What? This called Java Virtual machine. Okay. These the program These of an application that you can install these a platform that you can install on any computer on android Lanners. You can find it here. We can you know, type job you call machine download, and we're gonna downloaded later. We're gonna need started, like, for examples on an agitator. Other things like that. And this thing is gonna change bite goat into zero and wants okay. And that's cool, right? It's gonna change this thing into bite code that can be interpreted on and a platform. That's why it's so awesome. But you have to also remember that you have tow installed the Java virtual machine. So without the Jelavic tell machine, it's not gonna be, you know, you're not gonna be able to run it. All right? Okay. So that's why java is so cool. So let's remind ourselves we're gonna answer later something like that that's not being needs an editor that allows you to write a code in place like that. And this coat is looking like that. I probably cars drive application. We gonna talk like, what is the public? What's public meaning with this class and other things like that, Right. And we gonna click, play like here, and it's gonna, you know, come pie, this thing. Right. So this coat the programming language into something good is called a pipe coat, and then the bite coat is gonna be run by Java virtual machine, like in time, just in time because, well, you know, you might be like now a This must be very slow. And you are right. It is slower than the c++ solution. But, you know, you have to choose this or this you won't spit or you want to support all platforms. But it's not also very, very slow because, for example, when you have got a code that looks similar, right, you have been a big golden next to seem out in some places. Then it's gonna create in the bite coat a special, you know, instructions that is gonna make it simple, right? It's also not gonna compile all your code if some of the instructions are rarely used. If something is gonna be used very often, it's gonna even sometimes run faster than instead prospers, Okay, because it's gonna create special connections that are gonna make Ron things that that ran very, very often. So it really depends on situation. So Java, it's mostly slower. Sometimes it might be even faster than C plus plus, But the truth is that you shouldn't worry about it because our computers are faster and faster it day if you want Toe right applications Desktop applications are, for example, android applications. Things like that do not matter, right? If you have to use right drivers were speed really matters then C plus plus another longer Just are like C plus plus are very important, right? Okay. Remember that even games are written in Java, for example, popular games like Minecraft was creating in job. So you have to know that there is a process that is called a compilation here. Right? So the compilation is changing coat from one type of kowtow Another coat right in competition also you know checks If you do know you made some errors So if I do something like that that you can see and when I click play Hi, There are some errors, right? Onda Also it helps you de back your coat So you confined box the problems the heroes in your coat We talk about things like that also lighter We will, you know, installed the idea integrated development environments off the editor that has lots of useful tools and we'll talk about all these things. We also inside the Java runtime environment, which is which has got the Java Vittel machine inside it. We'll talk about all these things later in this lesson. You right now? No, Woody's programming language, right? The programming language is just some kind of set off rules that you have to follow in order to speak with somebody, right? The programming language is used to create programs. So instructions that are gonna be executed after changing it into the machine coat by our computers. So we are, you know, giving requesting computer what to do. It's like forcing team to do its commanding him. Hey, do something like, hey, go into the system and then out of it and then print a line like, for example, Hello, Ward. And when when I click play as you can see, we have got here Hello water We'll talk about you know why? He reasoned, told why here is a public how these rules work with each other in next lessons. Remember that you have you have an IQ questions Just ask me. I really love helping other people. That's only good lesson. Thank you very much. 3. 5 reasons to learn Java: Hello, my friend. Today I will tell you five the most important reasons why you should learn Java. In my humble opinion, the most important fact is that the Java is the most in the month and highest paying programming language. Why do I think so? Because there are indexes like, for example, Tai O B programming community index. And as you can see in this, an indicator off the popularity off programming languages. And as you can see, this index is calculated using the global being a whole vic wicked bad. They are Amazon and other very popular services. And as you can see, Java is the most popular language. Okay, so it's worth tolerant because it's gonna be easy to get the job. As you can see, we can take change, check other websites like, for example, indeed that girl and as you can see, Java is also very high here. Okay, so why is also worth to learn Java? Because it is gonna work everywhere on every platform. When you write a program in Windows, you can run the same program own for example, Lennox. Okay, so it's very cool, think and there is lots off resources on the Internet. Okay. As you can see, there are very cool resources with a full documentation off each. Classes will talk about class or classes later. It is very, very cool because, well, java is an old language, right? So you can find lots of useful information in the Internet. People will know how to help you, right? If you have any problems. And, well, android under it uses Java to create applications. Right on Drew. It is the most popular on the mobile devices, which means lots off jobs for Java programmers. And it also means lots of cash. And the last reason is that Java, I think it's easier to learn than other languages. Like, for example, C or C plus Plus, Why? Because, well, you do not need to worry about things like pointers. All things like that are taken care, but by Java. Okay, you don't need to worry about things like that which are just hard to understand, at least for beginners. And, well, you know, I'm gonna t do the java, so I'm sure that you're gonna learn pretty easy because I have got a special method for teaching other people. Remember, If you have any questions, feel free to us 4. Who am I: Hello, my friend. You might be wondering if it is worth to learn from me. Who is the person who's gonna teach you in these cars? Well, my name is our cathedral dodging, and I have got lots of experience in programming and Web development. As you can see, over 20 years stand in programming and 14 years time in developing websites, and I've also created lots of video courses. So I have got lots of experience in creating video courses, 27 in Poland and seven in English. I am teacher off thousands off satisfied customers. There are lots off sample comments about my courses, and all off them are positive. There is no bad review off my courses because I always try to explain everything from the bottom of my heart. I love teaching other people. Really. If you have ended to tell any questions regarding cover topics, please just ask me. I really love helping other people. I will help you because well, that's what I shall do, right? If I do something wrong way. If you know I teach Abed way some some something the bed way, the way that you will not understand it means that it is only my fold, right? It is my fault. Did I told you it the bed way? I have to do it a bit different way in order to make you understanding. Okay, So if you have any questions, feel free to ask. If you do not like my course, you can take a full refund after 30 days time. That's only that lesson. Thank you very much. 5. Downloading and installing IDE and JDK 13: however, bother in the people's lesson you learned Will Java is. You know now that it is a programming language, it's time to start using this language, right. But to do so, you need to write down the code in some kind of plates. So you need something. Would is cold and editor. It would be great if that editor would tell you what you did do wrong in your code. It would call her former the code to make it easier to read, to take her off, compiling your coat. It would do stuff that you would normally have to do manually, right? So as you can see, this editor has good lots off tools and together they create environment for developing programs. And that's what we need to download something would. It's called I the team, which stands for integrated development environment. I think Nat Beans is one off the coolest free editors. He as you can use it for free. You can use a different ideas like, for example, intelligent. They the community version is free. Cleaves with us to the A coat. It doesn't matter to be honest, which Editori you go now use in this cause you configure, discuss using any I D. You want. The editor should mainly sit you as a future programmer. So it's good idea to play with different ideas and find the one that will suit you the most . Okay, so let's Donald Net beans, Let's go here and click on download. And as you can see, the newest version is here. So we're gonna click download and here we gonna click on Windows version. You have Lena's quick ear, you have marked the care. So I'm gonna click here and then here, and it's asking me if I want to Don't know it. So it's being downloaded right now. And if the interface off the page we are on right now has changed, don't worry. I've added the link to this installation as attachment to the resources off these cars. Okay, so can download it under these Lecter before we install it. This net beans when you don't want something goddess called J D. K. As you can see, I have already downloaded it at this. I cried. And, uh, why is that? So what is J. D King? Well, let's type Jay Dickey don't. And when we go here you couldn't see here is Java platform. Dre decay. 13th is a version when and go here. Ah, even notice that we have here something, Jay. The Key Java Development kit Standard edition. And this is a kid, as the name suggests. So it's consists off compiler Javito machine libraries that are essential for you to be able to program in net beans, for example. Right, Without it, you won't be ableto even insel net. So you need to download. It is crucial thing to do, and in order to do it, you just access license agreement here and click on, for example, here because we want Windows version. But we won't use the official version off Java Development Kids. Why is that so? Because, as you can see here, is reading something like that. The newly licensed permit Silton uses, such as personal use and development use at no cost. But other uses authorized under prior our or Ike O. J D. Carr licenses maybe no longer available, which means that you need toe well, if you are getting money from writing programs, you need toe biden the subscription costs, which you can read more about here. Fortunately, for us. There is an open version that you can download here. Okay. However, I highly recommend downloading from it from this website because installers from these websites are easier to follow. Easier to use. You won't need to bother using this open side here. Okay? I highly recommend using the Adam Open, J D K. And he We can choose the version we're gonna choose, then you What's one? Don't worry. There is version 14 because they have some. They have speeded up the version so much lately that even programmers do not care about, to be honest said that they change versions so fast. Right now, people are really using diversion aid right now, But they create new versions because, well, somebody to pay for it. Right. And you are wondering, probably now, what's the difference between the free version and the paid one? Well, there are some sometimes security breaches right in programming, and they will be fixed faster in this addition. Okay, in the one that is official here, they're gonna be fixed. Oh, but a bit later, right? So you have a big company and probably want to focus on this. Maybe we are just learning give You are not doing any big programs. Definitely. Just don't even bother to use the official addition. Okay, because other things are the same. So when you click here on other platforms you were not is that we can choose also Line oaks . We can choose the mark. We cannot choose windows, so let down on it. Here we're gonna choose J decay, which includes already Ah, Java runtime environment, which includes Java virtual machine. Don't worry, if you don't want to remember by hartal these deprivations that I presented here, the most important for you right now is to just install weight and focus on programming. Okay, so we go not insult. J d k saved a fine. And that's way the second. Okay, let's open it on and says that it is executable file. Are you sure that you want to open years? We are sure. Okay. Ah, let's run it. Let's now click next and let off course. Read the agreement. 30 ik next here. Remember to choose deception and deception than next install and just wait a second. It's time to go like finish and now we need to installed in advance. So that's do it. The process is easy. Off course. Reach agreement. Except next. And here it found the J dedicated. We have just installed Eve. You don't have anything here. It means that J. D. K. Wasn't installed properly. So? So I do instantly the game. Next you can check for Rob. It's good idea to check for updates. Install and this process will take a wine about free. Five means really depends on your computer. Okay, The installation completed successfully so we can just finish. And that's only lesson. In the next lecture, I will show you how to create your first project. Where do we pull? Put your coat. 6. Creating your first project: how long? Today I we show you how to create your first project in NAND beings. In order to do it, you creek on file, then new project. And then from thes categories, you can choose at template. So how Your starting coat should look like it's just gonna hell, Bill, you don't need to create, you know, basic fights each time again and again just does it for you. As you can see can program in html in the pay PHP. It's just up to unit beans issues also for other programming languages. But we gonna accuse Java with aunt. What is Aunt aunt is You know this small being I don't know. Just kidding On is a build script toe build, run and debug your project. OK, so there is a great of maven. There are differences. To be honest, it doesn't matter for you for now. What are the differences between these building tools? Just use Aunt stick with it. Don't worry about these names here, So focus on Java with and and we do not choose job application because we want to create job applications and then we click next. And here we tied the name off our products. So, for example, name off my project, right? And then I click finish. And that's how we've just created our first project. Dead is called Name off my protection. As you can see, I d, which is integrated development environment has got here Lords off tools that we need to learn about. For example, here on the left side, we have got something like a project manager where we can see folders we've defies that we are currently working on. We have got now on the 15 that has been automatically created with that ham play that we used. And this is the entrance to our program. As you can see, it says to us to do called application logic. You're so when we right here something like, for example, this off course. Don't worry. What is that? Because we go now, explain it better in the future while I'm going to explain. But in future and when you click play button, as you can see, we have just compact our program. We have build it, and here we have a result. That's cool, right? We didn't need to do anything manually because everything was done But by this integrated development environment here there are there is lots off others starve like, for example, his story you can see also I did today something like these are so I changed using to diesel. As you can see, it can help you follow it. What you did in there current day over the last day. Durham Any useful stuff in idea? We will focus on a few of them in the future. Lectures step by step. So don't work for now and not is that idea is also polarizing the key words like for example, class public. Of course, we're gonna talk about things like that in future. Would they mean? But no. Is that because off it your cold looks better, right? You can, you know instantly is also he was because all so here is a public thing, right? Also he's here is by maintain anything you can instantly see. We see where is what? Because it's colorizing your coat does not all not beans can help you also sport errors like, for example, as you move ask you as you can see when we move here, our course or close inter first in unexpected Also, we expect kids, something good is called class. Okay, Now everything works fine. So when you make errors, you gonna be informed about Let's remove the column from here. Expected. Okay, so let's Audi bag in. Our program works fine. Now, this is pretty cool, right? Because, well, people tend to make me steaks, and you go now, make thousands of them, and this is pretty normal, especially of your beginner. But even if you're advanced, you're gonna make me stakes while you are programming. This is normal. So do not worry about it. If you feel like you are outcast or something like that. No, this is pretty normal begging, so don't worry about it. Okay? There's only good lesson. Thank you very much. 7. Comments: Hello Today I would tell you what are comments and why it's worth to use them. So I have created a new project that I called Commons application. And as you can see, I have got here some coat. And between this coat, I have got Colman's like that. So everything that is colored in gray by the editor is a comment and it means that it is not gonna be interpreted by compiler. Okay, so this is the place where you can give at the shoma information about your program because normally, if you did something like that, for example, this is a public law us A secrecy. The compiler is trying to interpret this thing all these tax here. But if you do it that way, we just one line comment. You can do it pretty easy, right? You can comment your coat. So why would you want to come and your coat? Why spend your time doing it? Well, because we are people and people forgets thinks like right, we are just human. So we are not perfect. And because of it, after you ride your programs and when you come back to your programs after even one month no, one year to year or three years, even after one month when you come back to your program, you know, gonna almost remember anything about it, Really? So that's why people are commenting things. And that's not the only reason. The second reason is that you can. We work in team, right? You can work work with many people at once, and they will not understand your coat instantly. But with comments, it's gonna speed up the development process of your program off your perfect application. Big application, right? That's why it is really very, very important to commandeer coat. So there are two types of Commons one line comment, which allows you to comment here, as you can see. But when you could enter you cannot it see animal common, right? It's not gonna on comment this here, and the more you want to have multi line comment well, you can do, of course, something like that. But, you know, we do take lots of time if you want. If you wanted, then delete something right from middle, for example, like that black you can use something will discover multi line comment. You just type slash than the mastery sign sign. And then you can type comment right on this. Considers editor. Automatic carry automatically changed on that Well inserted here. Ah, this science. Right. So now you can have multi line comment like that. You have probably noticed that that generated comments that are here have good additional asterisk. Well, you don't need them here. They are just here, so it looks better. But there is a small difference between this and this. If you start it come in like that, it's gonna be later used for the Java documentation. Okay, there is a program called Java Doc. We just generate a documentation, so there's a pretty big difference here. We gonna have a special lesson where I'm gonna teach you how to create properly comments. But, you know, we cannot do it right now because we don't know what it's class with. Our arguments have to send them whether functions other things like that, we gonna I'm gonna show you everything like that in future lessons. For now, you just need to remember that you should create your habit, a habit to come and your coat know everything but things that are just a bit harder. Okay. It's good idea. Did comment your coat Because it's gonna save you lots of time, not only for you, but also for your future team. Okay, there's only good lesson. Thank you very much. 8. Basics: Hello Today we'll talk about basics in programming in Java. Language. Well, the first thing I would like to tell you is that when we remove Colman's we have got here something will discord y spaces. White bases are enters Taba. Laters spaces. And, well, they're not interpreted. As you can see, I can play it. Well, I can have everything in one line. Look what we can do it even like that bomb bomb on bomb. Everything is in one line, right? It doesn't matter for the compiler, it is a computer, right? It is just gonna interpret everything like it's, you know, formatted well, but you should form of everything pretty well, and you should do it the way that I will do it in the future lessons. Okay, If you follow how I format things, your code will be read able not only for you, but for other people. And this is very important to I understand, right? So, for example, instead of writing a plus B, you can write a space blast space be It's gonna be easier to read. And well, I'm talking about these wide spaces because well, you need to know that what we can write everything in one line because off things like, for example, semi colons, You have to remember that after every instruction you have toe ended with the semi colon, every instruction is a common toe. Your computer, What is a common? Well, a coma instruction is just forcing your computer to do something. So when you write something like that, you say, Hey, I want to include a package called Basics We just here. If we had more fights here, it would mean that you could use all informations from other fights like that inside here. Right? So that's why you have got the package named Basics here and well, right now you know what is package right? You can include other packages from other people on that were created by other people on Did you can use then thinks from there. And what are these things from there where they are classes here is a class created automatically by our net means, right? This is the main class. It is public with this public weight. Well, it doesn't matter. It's just a modification. Er you just need to know that for now, it ah, the main class has to be public on the main cause. We were just You know, that class that has good the name magnify. Okay. And, well, what is a classy might be Wondering. Also, a class is just an container, a container for things like properties which are gonna describe something like, for example, a window. We have got the window, he right, And these window has good work with Hi. And you can do things with that life. For example, close it and you can, for example, maximize it. Neymar's it, right? You can do thinks with the window and things like that are gonna be described inside the club so we could create a class. We work a window and inside of it would have properties like waves like high. And we could create a function which is something like that that could allow you to close it open. And as you can see, here is a matter which is oclock, which is a function, really. So this is similar name, right method function, and it's called main. And the reason this function is here that it has toe execute all instructions that are inside of it. After invoking that main function is very special because it's gonna automatically be executed after creaking here place. So we would create an instruction here. So, for example, system, which is a class somewhere. And when you get to something with this out, which means that we want to get out something from the system, right? And we want to print something. For example, attacks life example, sample text. This thing after clicking play is gonna be printed here, as you can see, So these function is gonna execute other functions, other instructions. As you can see, we have a tour, a semi colon, because this is an instruction, right? You have also probably noticed that here we have a good carol Abrasives, Kerry braces say where? Well, you have to say where there class is starting. Right? So the basic class start from here and ants here, right? You don't use semi column for it because, well, you have semi column here. Still, the compiler wouldn't know. Well, I decepticon is for for for what? For these crowds or maybe something else. Right. So that's why we have good care of the braces. And method also needs to know where it has to start and where it has to end. So here we invoked. So it means that we what we use somebody called that this start inside the print function and this print function is, as you can see, after kicking place showing something here, and we're going to create our own functions in food future lessons, you're gonna learn lots of functions from libraries that are gonna help you, for example, create a window like that one or, you know, calculates something. Cup. So this is the reason off creating functions and that's how you use them. These the basic functions that we're gonna use in the future Lesson. Keep in mind that this is a very, very fast introduction, and you don't need to worry if you don't understand that. Well, what is that strength in? What is that? Think here like that. What is vote with this study? Good is public. Why you didn't tell me about this? Doesn't matter. For now, you just need to know that this cult is gonna be invoked first. Okay? And later we go. Not. I'm gonna introduce to you something like vory bulls than alright, then We're gonna go to the functions, matters and other things like that. Why do we have modifications like that? That what are exactly classes? How to create them? How toe, you know, connect it. Medical, many classes to each other, other things like that, right? For now, we want to know that Main Functions is a special function that is gonna be invoked as a first function. And it's gonna invoke all possible instructions between discovery braces and this curly brace. Okay? And we gonna learn the syntax of Java in future lessons. That's forward for now. Thank you very much. 9. Shortcuts: Hello. Welcome In their balance section, where I will show the most useful short cover. It's gonna save you lots off time When you gonna develop programs, your own programs. Why? Because you know, using your mouth is just a bit slow when you have to say things off, for example, five. And then do they go to the safe here? It just takes someone you to copy something. So when you do things like that, mouse is just always slower. And you have to remember that you gonna spend lots off time writing code as a programmer. Which means that E knowing all these short cuts is gonna save you time each day. And when you multiply it by the days that you're gonna program is gonna save you lots off days off your very precious life. Okay, so let's start from this first shortcut control plus s from, as is from safe. And it's just saving the fight you have. You will notice that when I change anything in the program that you have got here a bolt bold it fine. And I hope I'm automatically saving, always using the counter process. Why? Because well, when, for example, I would lose the power, right? I would lose all my work. Right? Some editors. Can you get back to the place where you have lost your power? But some doesn't. And this is the universal Ah, shortcut. You can using an editor. So it's very important to know the next one is used for toe copy things. Well, you know, it's slow to company things like that. Balm on Go. Oh, here is a copy and then enter here and paste. It takes lots of time. You can just use control Potsie than control plus V And this you consume can copy. And as you can see now, when I didn't want to have a change like that, I can go back. Using the Contra Palazzi days is very cool shortcut because it allows you to go back when you did something to your Cody. Didn't want to do right. It's very, very useful. These did well and but sometimes you might think it a bit too many times and you can use the country plus why it will redo the action. Okay, so you can go back to the place where you started going back and whether you have. You can also cut something so you can you know you don't You can copy, but in the same time, cab, the thing that you want to copy from the place of for example, remove it from here and ties it here. Right? Okay, let's go back to that, uh, origin or fight. And let's now find out what is the counterpart? F shock. When I use the counterparts F as you can see now, I can search for things inside our products so I can fight, for example, main function. I confined. For example, Where is the public key world? Where is the package or other things like that? I can instantly find things on. It. Really has you a lot. Almost. An editor has good. Something like that, even in the Web. Brother, when you're browsing for something, it's very important because you're gonna browse for two to learn about libraries for Java, for example, and you want to find something specific about Java. You can just use the contra plus F in the Web browser, and you can find it faster. Okay, so it's very useful Shortcut control, plus a which sends for all, and you can just select all things from your from your well program. Why? Something like that is needed. For example, you can just do something like that. Now they control plus C and you can paste the code from here to, for example, a place where you going? Toe. Ask somebody. Why doesn't war, right? You can come from Passaic Controversy counter plus food V somewhere else. So it's very useful control plus back space. Sometimes it's gonna happen that you want toe deal it something like, for example, award to write. The truth is that you want to, for example, remove a variable but we'll talk about a very poor state. And if the name of a rebel is long Oh, so you need to do something like actually basically sleep exit right. But you can also do things like counterpart class backspace And as you can see now you delete full work at once. So it's also cool and this thing is also very useful. It is top and chief, plus stop thes one. You probably know, but this +10 this is very useful. And many people doesn't know that you want. You can go back with your indent, right? Would. I mean, let's create a variable in. And that's a sign here for we'll talk about later, things like that. But you know, physical and we are checking if a is equal to four. If yes, then I want to pray into the output ball or something like that. And well, as you can see, we have go to an Indian and sometimes you might have a problem. So, for example, you you have a cold like that. Oh, it's not looking good, right? You can go back using the shift, plus stop it. You can see you can go back using something like that. And the cool thing is also that you can use the top toe move manner as you can see things at once, and you can go back also. And well, waters, you have got here also, something called is called and and home on your keyboard. When you're for example here and you creek home, we are at the beginning of the line when you and your at the end of the night and when you I want to, for example, copy something like that, you can do something like shift plus home and, as you can see now have got selected line. And now we can use the counter policy and now concretely and and then enter. And as you can see now, you can copy it pretty easy. Was more You can use the shift and the arrow keys to select more than one online. You can also use the left and right arrow key to select specific. You know, as you can see, um, character and then you can copy writes a country plus seconds plus V on bom bom bom bom bom bom bom. As you can see, it really improves the speed off cop eyeing things on your in your prose. Of course, I'm doing things like that very far. Right now. It might be new to new things to you, so just train. You just need to train. And finally, you're gonna know all these shortcuts pretty well. You have got all them all described. You can print them so you know, just drink and you have got also something Go Discuss control plus home, which allows you to jump from the place where you have got your cars are okay so you can jump from here to the home, off your program and to the end. It's very useful because it can. Sometimes you want to go to the top of the off the program, and it's also useful because you can use the shift plus and a ship council plus. And and, as you can see now you are selecting with using something like that, right contra plus shiftless and allows you to select from the place from the course. Of course, a place and home life it There is also very important shortcut for these editor. When you take, for example, stuff like system, then you click a dot that you can see you have got you a man manikins, right, But sometimes you can lose them. You can do something like that, and you want to somehow get them back. You don't need to delete the dot in order to see the game. You can also do something contra plus space, as you can see. Then you get get Sheen's like that, so it's very useful to get him. You can also use the control plus space to, for example, create a coat like, for example, I look for as you can see, then you can just change things here. And you have just created a pretty because this is called a snippet drive. You can create a sniper's like that, using the control plus space. And I want to check if something is true or not. So this is pretty useful. A Z you can see wide Look, another things like that. Um Okay, so that's going to listen. Just trained it. Thank you very much. 10. Variables: Hello Today I will tell you whether we're Abel's. What is a type of a Rabel? What type off variables you can create so ever able is a container that you can use to store information data like, for example, numbers, characters, other things like that. So very booth are looking like that, right? A container that you can name and you can put something inside and well, the true vis that it looks more like that you have got a ram, which is random access memory. Yes, that's why you need rum. You want to reserve something from your random access memory, right? And when you do it, you can starter, for example, numbers, characters or floating numbers. So numbers like that and have to do it. How to give an instruction to your computer to reserve something from the random access memory. In order to do it, you type something like that in the main mattered and a for example. So I have just reserved in the random access and memory at place for numbers for in teachers. It stands for integer right, which is a number, and now I can stole their a number. How to a sign there a number. How to change the value there, Right? In order to do it, we talked that equal sign and then we say what you want to assign there. So, for example, 10. So right now we reserved in our random access memory because he's an integer integer is saving 30 free bits, which is four bites off your memory. So yeah, it would take for more bites. Your program will take former bite when you click play and well, you assigned her 10 right? This assigning is called initialization when you assign a volume two variable the first time so you can later off course change these value. Or of course, you can also send you to the airport using their for example system out print line. This shortcut life just used is when you typed the sea out on you kicked up, as you can see, then you don't need to type all this. Think again, because off the net beans, I d. So I just sent 10 on the outward. As you can see, it's working fine. And of course, you can change these value at the time so you can change it to for example. 50 on as you can see now it's 50. So that's how you change a value. Well, variables are called like that because they are able toe very, which means they can They are able to change right on. And we have just changed the value off. They're very able like here, which can start off course only in teachers, which are numbers. So, um, we have to remember to be careful to not set something like that, right, Because this is called string, which is sequins off characters. You kind of start characters inside different container that has got the wrong type. OK, so we need to learn about all possible types that we can use. So we wanted to start here something like, for example, string. We need to type string. Then, As you can see, we can easily start something like that. So, for example, my name, right? And of course, Aziz, you have provided noticed. I can't assigned to a string a number, right? You can change the value too, the different type volume. So, when I played as you can see, here is my name. You can of course, create and well, you should name in the big betters off example name and now my surname. Right on Now we can something like named plus starring Plus is used to connect to three things. And as you can see now it's our Kardashian for Dr. If you want to add the space, you're just gonna do something like that, right? Our country is for Dutch. It's just that it Ah, some space here, right? Using this quote signs. So that's a string we need to something in common that's created live as described Would we have just learned? So there are integer types like the end and it's 30 feet bides Let's go. Paid here from here and well, you can start there from minus two to the power off. 10 to 1 to to to the power of 31 minus one. Well, we could go into these a bit deeper. You just need to know that you can start values from that. Ryan arranged to another run. Tried. So when you do something like end A, you can on the same here or something like that, because they say, you know, this number is just two large. Okay? It's too big. You cannot do it. But hey, what if I wanted to assign here something? Because, you know, sometimes you want to do some scientific stuff. Then you gotta use for example, long, Long is 64 bits and you can start their numbers from minus two to 63 to the power of 60 feet too. Two to the power off, 63 minus one. And when you do stuff like that, as you can see now, it doesn't work still, but is because by default and the number looking like that is in teacher, if you want to change it to the long you need toe, do something like that. You need to type. But the n l let's do it with the big letter so we can see right and no when the get it to the output. As you can see, it's working. We did it that way. It's not gonna work if we need it. For example, that way it's also not gonna work. OK, so we need to add this l at the end to say that you know what you are doing. You want the big numbers here, okay. And well, what in the other in teacher types that we have. We have got some short like, for example, by which is a bit bite is really a bit so it's nothing surprising. Thing is the smallest amount off information you can start one beedies smallest information can store in your computer Which 01 right and, ah, the the ranch from is from minus 128 to 127. So you gonna use the bite when you don't want to start big numbers like that, you want to start just very small numbers. And you I don't want to used to march spacing your memory right. You're going to save your memory. You can also use the short integer with its 16 bits and you can start their from 32,078 miners 7 32,768 to 33,767. So something like that right on you can start the just beat bigger number between this thing. Okay, so these are in teacher types and now character types. You can use the character time to store a character. So example was carried the character and let's assign here a character like I and let's get it did output. And as you can see, we can see character. You can start on the one character. We're gonna do something like that, right? We want to do something like that. You have to use the string which can start sequence of characters and look at the difference Here. Here we have double quote right here. We have an apple stuff, but its single call. And well, if you want to create a stringing to use that one, you want to create a character single Carter, you have to use them apples through a single quote. Right? That's very important to know. So off course there is a string which can start many characters. All right, so the one that we have learned here like that there are two more types jaar cult floating numbers, which allows you to store numbers with a fraction. So, like, for example, that right, In order to do it, we should use the type that this called float double, so float. It's single procedure, which means you can lose precision here. Onda double these double precision, which means that it's better to use the princess this room is that right? Now, almost nobody is using the floor because it's mine. Give you more headaches. Good things. Okay, this is a good 30 fee. Book bits is 64 bits on these one can store 1.4 multiplied by 10 to the power of minus 44 5 So the fraction is very small. You can have fortified zeros right after the dot and to three point for multiplied by 10 to the power off 100 and 20 is 38. So it's very big number. And here is even bigger because you can start your 4.9 to the power off what minus 320 free . So it's very big on here, freak on there and that. But as I said, area to know these fault, Unless you want to server small number and you don't want to almost when the operation. Okay. And you really, really want to save the random access, more memory, which we have. Tom's off off the right hand right now. So big that we shouldn't most time care about something like that when you But if you do not need to do any preparation, need to store a number that is, You know, you don't that doesn't have many things after the dot. It's then. Well, yeah, you can use the float, but there is a small problem when you carry the float, for example. Number. Right? And you're saying here something like that, you notice that hey, he was something wrong. Have toe as it to float for the hell was going on. Um, when we do something like that, it's concede program is not working so flawed is not working at all. When we create a double its working for I'm fine, right? But double Well, any number that has good a fraction has good that is automatically adding here something like D D right, Which stands for double. Okay, now it working finest consisted for float. You need to trust us here, and f Why? Because, you know, some people could make this mistake to create float number, not knowing that it's single precision, and it can create for him problems that would be very hard to solve. Okay, so that's why instead of flowed, it's better to use just double okay, unless you don't do an operation on these numbers, it's also good to know that when you are creating vory bulls, you can create man at once. We can create something like end on. Do you can do something like C d E f g. Right further the problems. It's good idea toe at your spaces, so it looks a bit better. And, of course, you can initialize one off them for self, for example, like that. And it's gonna work fine. Off course. You cannot use the variable that is initialized, which means that it doesn't have have value. So you need toe to something like that. Okay, designing that lesson. Thank you very much. 11. Naming convetions: Hello. Today I will tell you about naming conventions for variables. I would tell you also what you should and void. So naming conventions means how you should name your variables. The first thing you should remember that you should net create a variable that should be said the script, which means that it should be like when you look at it, you know exactly instantly what it's gonna be useful. Okay, So when creating a were able and you call it a pet idea of course I use it in the last lesson. But it was just do fellow you how to create a variable. But you should avoid situations like that. Your were able should be said that script. So if you are creating a string that we will star names, you should call it name. Okay, It's gonna store starting. Call it Starling. So surname our cop. The second thing you need to know is that there size of letter or future terror matters. So if I want to change these name, I shouldn't type something like, for example, that because it is not gonna work. As you can see, it's not working because these vary but it is not the same as these words, right? These something like that. I'm just gonna create another variable, right? With just starting letter, which is big. And you should also remember that you shouldn't start name off variables with big letters Because these a convention variables should always start from the small case on. Then if you want toe, have you know something like name and signing, for example. Right? And you should be deadly. You should, for each word, try to have the upper case off letter. OK, so now it's you can instantly. Hey, it's name and a salmon instantly. Right? Oh, okay. Because if you call it a you don't know what this start here Exactly. You have to look at the value. Okay, Maybe these values very easy, but maybe these values sent from from the fire and you don't know exactly what it's gonna be right. So always try to name everything to be said the script and what you should know that you cannot create as the name over able as the label off. Vory bull, you cannot use keywords, which means that you cannot do something like that in public as you can see. It's just not working right. You cannot use things that are reserved. Why? Because you know, interpreter is just going well nine by time and line and is trying to compile it. How can Kinky complied when when he knows that started means something totally different, right? Uh, it's not gonna work. The second thing is that you shouldn't start creating a variable from the number, so you cannot do something like that that's going to see it's not working. You can have numbers inside. Like, for example, here here doesn't matter. But you cannot start from the number because, you know, then compiler things done that you're creating a number, not a very And the terrible thing is that you cannot do spaces so you can do something like that. Of course. Right, because, well, it's another work. There is a so one more convention that you should know when you're creating have a rabel that is constant, which means its final it's gonna be changed it like, for example, P number p. So, for example, in create being like that, I am gonna use, as you can see big letters, because it is not gonna ever train Friday is always free point for So when you're looking in your program, then you know which variables are constant final and which are which cannot be changed. And you can even say exactly Hey, I don't want these very will be changed and you type them final before it goes of it. When you do something like, for example, trying to change it, you can see you have a good an arrow. We have the final here because you can change pretty easy these without the final modification. So because just lentils with our motive IQ a tres they can modify how the variable is gonna working in program the final Leave it like that. And well, it's good idea that if you had more than one word in the final variable to do something like that, for example, number dash be okay. You're not because you're not gonna lose your hearing. For example, small case letter. You just we want to give that space there. You should used underscore because this is an read a book. This is readable pretty OK on. But that's that's how you should create variables. How you should name it. Remember self descriptive paraders are very important in order to make your coat clear and easy to maintain that telling the lesson. Thank you very much. 12. Casting: Hello Today. I will tell you what this casting casting It means changing a type of a Rabel into another type of a Rabel, and it is used in situation like I will show you soon. For example, when they create assistant outpouring line method and I do something like one divided by five, you probably think that he will have, as a result 0.2. But the result is zero. And when we do something like, for example, for Hey, it's closer to five. It should be one, right? No, it's easier. But well, if you don't five divided by five, then it's one. If you don't eight divided by five, it's one. If you do 11 it's too. Which means that the result off division off to in teachers is always an intention, right? We just take the fraction away and just throw it to being right. It's gonna be deleted. But, hey, I sometimes have situation like that, eh? Divided by being and I don't want as a result to hear. I want here 2.5 how to do it. Do I need to change the type of are able? No, you don't need to you can some times want situation like that, and then you cannot do it that way. You're gonna use casting If you want to cast a type of arrival into another type of a Rabel , you gonna type the parent is is than the type of Arabia we want to casto. Then the next parent is, is and the name of a rebel. You want to cast to another type. So right now you want to change the integer to double And if one off the variable iss double, it's enough todo the results So the result becomes, as you can see also double Okay, So if I did something like that see, divided by the it's gonna give us a za result off course 0.8 If I'd do see by being it's also gonna give us the as a result, the double. So that's how you use, you know, casting. But let's see eating other situations. So, for example, let's create a result unless it's something like that. A divided by B on double results too see divided by the and let's get it to the output. As you can see, the result is still of course, because five divided by two, it's 2.5. But the result is what integer Andi. Now imagine a situation you want to divide A by the way, you want to divide to different type of Arabe als. Well, you have probably noticed that we could do it that way right here it's gonna wear. But here's something is not working fine. Why? Because Well, he we just printed it out. But here in the line 11 we want to assign the result old into the ah variable called result . That type is end, right? We want to assign double into end and it's not possible. So you have to change the result into the integer. You have to say the compiler you want and you know what you are doing because you know here , as you can see, size incompatible types possible loss of conversion from double to end. So it means that hey, you can make make some problems here. I want to make sure that you are doing everything fine. So you have to use the casting right, but not to double but in teacher, because you want to change the day into their integer. So you have got the integer divided by integers of the result is in teacher and now everything works fine, Right, Because five divided by 15 0 upon free, free, free, free, free. But you gonna throw away the fraction That's how it should work because this is a, um, division off to in teachers. Okay. Ah, let's see what would happen if we did something like that See, divided by s So we want to divide toe maybe see divided by Oh yeah 12 Divided by five It's shoot. Give us the result. As you can see, 2.4, it's double because well, doubled by integer is double Okay, so you can assign double to double right? So everything works Fine. But if you want to see as a result here, for example, on Lian Teacher you could do just something like that. Hey, I won't hear a name teacher on this. You can see now we have got here too, right? We couldn't change it and the second to another time doing something like that. You also need to know that sometimes you can do things like that And as you can see, the result is wrong. So if you want to fast change the result to the right result, you need to change one of the type to the double right using the casting. But you can do it a bit faster. Way you can do just something like, for example, that 1.0 why it's gonna work is that because this is the two double type, the value off double unity is the point. But hey, you are so you're thinking like, right now in line eight, you're not using something like that. That's true. But in the background, the compiler is gonna change the integer into double here. Okay, It's because double has bigger precision and that's why it's gonna work, right? But as you can see, for example, if you do something like that, it's not gonna work because, you know, double cannot be stored inside an integer because double has good big gulp. Recisions can be a big number, and it has got lots of more buys and other things like that. You cannot do things like that. We've out exactly saying I want to change this into the indigent. I want to lose everything from you know, after the dot, right? You want to lose the fraction. That way it will be okay. So that is casting and the There was another thing. Another place. Where you gonna use it? It's gonna be used when we we cannot talk about polymorphous, but it's gonna be in the future lessons when gonna talk about object oriented programming for now, it should be enough for you. That something good lesson. Thank you very much. 13. Arithmetic operators: hello today. I would tell you what our operators and we'll talk about arithmetic operators. So operator is, as the name suggests, and operators of something that is operating on something in our situation, it's gonna operate on variable. So it's gonna do some actions on variables, and in this lesson, we'll learn about arithmetic operators. So, for example, plus miners mastery sign and the Baxter sign. As you can see, they are useful adding force, obstruction, multiplying and dividing. These are pretty easy one, so we'll focus on a bit harder one. Okay, so these only you just used by, you know, typing on the left side, one of arrive on the right side, done other wearable. And it's the same I give you didn't on math lessons. These are the basic operations. It's 100% that you know them. So let's focus on things like here when we have got the variable. So, for example, in A and I assigned to 552 years and we send it to the outward. As you can see, we have got five. What would happen if I wanted to increase the value inside that variable? A. By, for example, free what to do, where I need to do something like that. A assigned to a A plus free. So we are assigning here the value that was in a before So five. And now we're adding freeze of five plus three is eight. And because of it, as you can see, we have got at him. So in order to change the value without losing the last value, you have to just Assane the value that was there in the first place. You might be like about Hey, how does he know that here is five. The new value? Well, the instruction is gonna be always executed from the right to left. So first we're going to add five plus free, and then we assign the some of it to Hey, so as you can see, that's how you do it. But well, it takes a bit off space. And you know, every programming is programmer is a lazy person, but in the intelligent way so you can do Stipe something like that. As you can see, it's working also on Well, let's do this one. As you can see, we have got here eight. So we are plus five plus free is right. So these a short cut for doing something like that. Okay. Off course. You can also use it to do other things. Like, for example, let's remove. But let's subtract from this, for example to so we have free. As the result, you can see the result is free. You can, of course, multiply so we'll have five multiply biter. So it's stand five multiplied while divided by, for example, free. As you can see, it's one. Why? Because five divided by three is y 1.66666 And this is an integer Opara operation, right, Because there's an integer type. The result is also integer if we change it to double here off course, the result is having the fraction, right. Okay, so that's how use the shortcuts and use them because, well, these are very often used operations, so it's very useful toe know about them. You will surely meet something like that in your adventure when you're gonna program and well, you can also use something like incrimination and decriminalization. Implementation and dick lamentation allows you to fast at one or two the value to the original value or D cram in the original value by one. Okay, so for example, we could do something like that that a plus plus and as you can see, when we executed, we have got here now, six because five plus one equals six. Right and off course, You could also write something like that and it is the same. But I you know, it's shelter. So you're even more lady here. This is the most frequent operation when you are doing anything with looks that we'll talk about, for example, in next lessons. So these use very often so they even more decreas