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Java_D01 - Main Method || Data Types - [18-08-2026] — Transcript

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0:05Great. Thanks for the confirmation.
0:13Very good afternoon everyone.
0:16>> No energy on. Good afternoon everyone.
0:19>> Great. So I think probably
0:22you might be actually wondering who is
0:24this fellow who is what he's going to
0:26teach and all. So let me introduce
0:28myself. My name is Harshett. I'm a
0:30senior technical trainer here at TAP
0:31Academy. So from the last four years I
0:34have been training multiple students. So
0:36I have seen different different people
0:38from different different colleges. So I
0:40don't statistically remember how many
0:42people I have trained around 50,000 plus
0:45uh students easily I could have trained
0:47in the last four years of my career. So
0:49the faces which I'm seeing right now
0:51might be new but the problem the
0:54struggle everything is already known for
0:56me and definitely for whatever purpose
0:59you are sitting in front of me I will
1:01make sure that that purpose will be
1:03fulfilled and before leaving this
1:05classroom definitely you'll get that
1:07confidence that okay something new we
1:09have learned today and you'll be
1:10confident about that as well. So if I'm
1:12not wrong, I think probably if you're
1:14sitting in this classroom, you have
1:16decided Java is going to be my backend
1:19language. If I'm not wrong, correct?
1:22Yes. Why particularly Java? I need not
1:25to say of course technically I'll be
1:27speaking a lot but non-technically you
1:30might have judged Python and Java in
1:32different aspects.
1:34Probably for the very first time in your
1:36lifetime also you thought Python only is
1:38easy if I'm not wrong. Later you
1:40realized okay to become a amazing
1:43back-end engineer maybe Java is most
1:45preferred though it is difficult let us
1:48compromise on difficulty but you'll get
1:50a stable growth you'll become a a better
1:52backend engineer a software engineer
1:54these might be the decision making
1:56factors for you people if I'm not wrong
1:58correct or one more way is how many how
2:01many of you are computer science
2:03background students please raise your
2:04hands oh my god I have just asked the
2:06wrong question so almost 90% % of the
2:10people are computer science. Anyone from
2:12mechanical, civil, electrical
2:14backgrounds?
2:16Okay, a couple of them. EC and Ale as
2:18well. Okay, a couple of them are there.
2:21But let me tell you Java is one of the
2:24biggest nightmare for EC, triple E,
2:27civil, mechanical for them programming
2:30language means C if not Python. These
2:32are the only two choices they had in
2:34college. Not now in college. So then you
2:38decided okay language means Python we
2:41never know that Java existed actually to
2:43be honest this is the reality of non CS
2:47background students the reality is they
2:49don't even know Java is there correct me
2:52if I'm wrong correct so in most of the
2:54colleges people doesn't even know
2:56[clears throat] what is Java they might
2:57have not even seen Java in their
2:59lifetime but probably for most of you
3:02already certain classes have been
3:03happening from a couple of weeks for
3:06certain people over here Maybe one week
3:07of classes you might be attending and
3:09this might be your seventh class or
3:10eighth class but doesn't matter we are
3:13going to completely focus on Java from
3:16scratch. So what is your previous
3:19knowledge I am not bothered about it
3:21I'll be actually teaching from scratch
3:23and let me tell you if you trust Java if
3:26you have that faith in Java it will take
3:28you somewhere that you can't even
3:30imagine. So today even today in the
3:33world of AI no one even can touch a Java
3:37developer who is an expertise in spring
3:39spring boot and all AI will replace and
3:41all that thing only remove it from your
3:43brain. Even after 5 years even after 10
3:46years a person who is an expertise in
3:48Java will still be relevant in IT
3:50industry. This is one fact I would like
3:53to start with. So one more thing why
3:56particularly Java sir my some of my
3:58friends are in Python class in SBI maybe
4:01I just came this to this class to see
4:03what will what will be there in Java
4:05maybe tomorrow the same strength can I
4:07expect or not I'm not sure maybe in the
4:09one and a half hour you'll decide you'll
4:11judge should I be in this class or
4:14should I go to Python you will judge it
4:15in the next one and a half hours right
4:17don't worry I will ensure you'll make a
4:19correct judgment okay don't worry about
4:21it and one more thing
4:24Why Java? The main important question
4:26sir, Python is also there, right? Why
4:28Java? In my classes, I'll speak about
4:31Java only. I hope you're understanding.
4:33I'll not apprise or I'll not appreciate
4:35Python. See as a language if you notice
4:38both are equally important and everyone
4:41has their own use cases situation based.
4:44But in my classes, I'll appreciate Java
4:46only. And you should not think this
4:47fellow is partial. I will be partial
4:49only. Are you understanding? because you
4:51have opted you have you have seriously
4:53selected that I want Java so I should
4:54speak advantages disadvantages also I'll
4:57speak but moreover why Java is what I'll
5:00be focusing on rather than why Python I
5:03don't want to make you to feel regret
5:05why you did not select Python I hope
5:07you're understanding so coming to the
5:09fact why Java I'll just give you some
5:12reasons you can just make sure that yes
5:15I took a right decision today any
5:18application that you're using if If you
5:20go to any shop, you'll make payment,
5:22right? How do you make the payment? UPI,
5:24which is nothing but phone pay, Google
5:26pay, uh, razor pay. So, different
5:28different options you have. All the
5:30banking application back end is still
5:33Java only. And even 10 years later also,
5:36I'm telling you, I can guarantee banking
5:39application backend code AI will not
5:42even touch.
5:44Company will never allow AI to be used
5:46in the banking softwares. I hope you're
5:49understanding. So large banking systems
5:52especially you might have heard JP
5:54Morgan similarly Goldman Sachs. So like
5:58this there are top tech banks
5:59international bank companies where still
6:02the back end is job still there are so
6:04many openings even today but the reality
6:07is that opportunity will meet only the
6:10right person. Opportunity is there but
6:12it will only meet the right person. Your
6:14fundamentals should be super strong and
6:18your syntax is actually the most
6:20important thing when you are writing a
6:22Java code. What is a class? When to
6:24create a class? When object should be
6:25created. So different different thought
6:27processes are very important.
6:30Architecture level thinking is important
6:32to get into that companies.
6:34One more thing today most of you are
6:37using applications. Whatever phone pay
6:38you told where are you using in your
6:40mobile phone every mobile phone will
6:42have operating system and in India
6:45almost 70 to 80% of the users are
6:47Android users and Android is an
6:50operating system it is a software only
6:52right the back end of Android is Java
6:55most of the top tech companies like Meta
6:58and FA that is what Facebook or Meta
7:00both are same Google Microsoft and most
7:04of these companies also they have
7:05multiple products still Java only is
7:08preferred. So which means a job which
7:11can pay you 3.5 lakhs peranom all the
7:13way till 35 lakhs peranom in this entire
7:16broad range Java has a lot of relevance.
7:19So enough appreciating Java let's go
7:23into technical part and understand all
7:25these things. Anyways
7:27already few knowledge you already have
7:29about Java right. So Java is a
7:32objectoriented language. It's a platform
7:34independent language. It's a robust
7:36programming language. A lot of features
7:38you might have gone through and we'll go
7:40deeper into every feature. And few
7:42things I would like to ask you people
7:44before me speaking. What do you mean by
7:46platform independence?
7:51>> Huh?
7:55>> Okay. Can you see already problem
7:57started? What is the problem? Not able
8:00to answer the question which already you
8:03know isn't it? Do you know what is
8:06platform? Yes. So operating system means
8:08platform. We already know. You know what
8:10is independent? Yes. Not being
8:12dependent. So Java is a platform
8:16independent language. Which means Java
8:19doesn't care which OS you're using. Long
8:22story short. So compilation can happen
8:24in one OS. Execution can happen in any
8:27OS. This is the feature of Java and
8:31Python also. But I'll not speak about
8:32Python. I told you. So why Java is very
8:36famous if you ask me this is the number
8:37one reason and trust me today whatever
8:40software that you built in Windows can
8:42be used by Mac user also can be used by
8:45Linux user also but the problem with C
8:48and C++es you need to compile in every
8:51operating system to serve all the users
8:54that is the problem who will develop
8:55again and again so that is the first
8:57thing and how did Java achieve this is
9:00the next question how
9:02because of to important changes that
9:04happens the compiler the Java compiler
9:08will never give you zeros and ones it
9:10will give you something known as byte
9:12code and what is the extension of byte
9:15code
9:16>> class dot class if you did not
9:19understand I will write a Java file I'll
9:21save it what is extension dot Java if I
9:25save a C program C for C++ CP for Python
9:29py so for text file notepad you'll type
9:32something you'll save it. What is
9:34extension? txt pdf means dot pdf like
9:37that byte code also will have an
9:39extension no that is dot class that is
9:42the extension you can't understand what
9:44is there inside that who can understand
9:47only one software can understand that is
9:49java virtual machine so java virtual
9:52machine the primary task is to take byte
9:55code convert into zeros and ones and
9:57execute it. The next obvious question
10:00they can ask you is is JVM platform
10:03dependent or independent?
10:06Listen to the question very carefully.
10:08Java you told sir platform independent
10:10we know it. JVM is it platform dependent
10:13or independent?
10:15>> Independent.
10:17>> Dependent.
10:18>> Are you sure?
10:20>> Okay. JVM is platform dependent because
10:24in my Windows OS I can't install Mac OS
10:27JVM. Right. It is specific. It is
10:30dependent on my OS. Are you
10:32understanding? So this is one thing you
10:34should understand. Java as a language is
10:36platform independent. But JVM as a
10:38software is platform dependent. Don't
10:41get confused. Are you understanding? So
10:43this is how the architecture of Java
10:45looks like. So high level give it to
10:47compiler. Compiler gives you byte code.
10:50Byte code will be given to JVM. Next JVM
10:52will give you zeros and ones. So because
10:54of this byte code and JVM it was
10:57possible for you to achieve platform
10:59independence. So in an interview if they
11:02ask you can you explain how Java
11:04achieved platform independence. How
11:05would you answer simple don't buy heart
11:09when I give an answer answer like this
11:11it need not to mean that you should buy
11:12heart it's a framework oh step one step
11:15two step three point wise first explain
11:18what is platform independence. So, Java
11:20is such a programming language which is
11:22not dependent on OS. It can be compiled
11:25in one OS. It can be executed in any OS.
11:27This is the meaning of platform
11:28independent. Coming to the point how it
11:30is achieved. Simple same architecture
11:33you explain. So, compiler gives me byte
11:36code. That bite code is given to JVM.
11:38JVM will actually execute the zeros and
11:40ones. So, this is how Java has achieved
11:43platform independence. I can compile in
11:44one OS, execute in any OS. This is how
11:47you need to explain. And also Java is
11:50not dependent on your microprocessor
11:52also. You use i3, i5, i9, AMD, Ryzen 5
11:57doesn't matter. So it is architecture
12:00neutral. Architecture means what?
12:02Design. Whose design? Not computer
12:06design. Microprocessor design. I hope if
12:09you are a computer science student at
12:11least some somewhat technical knowledge
12:13you'll be having, right? Every processor
12:15has a different design, different cores,
12:18different threads. You might have
12:20noticed, right? So 60 bit uh 64-bit
12:23processor, 32-bit processor, every
12:25processor is unique. And the fun fact is
12:29just in i5, you know, right? Just in i5
12:32only 10 variants will be there if you
12:33don't know. So processors are having
12:36variety of variants. So is Java
12:39dependent on it? No. It's architecture
12:41neutral. It's also known as a portable
12:44language. Why? Very simple. I can
12:46compile over here. I can execute in all
12:48of your systems. It's easily
12:50transportable. That bite code I can send
12:52it to you. Are you understanding? Easily
12:54transported. So these are some essential
12:56features which you have seen. Later you
13:00understood there is something called as
13:01object orientation. The most important
13:04principle. I think some fundamentals
13:06were explained for you. What is object
13:08orientation?
13:11C++ is object-oriented. Java is
13:13object-oriented. JavaScript is
13:15object-oriented. Python is
13:16object-oriented. Scala is
13:17object-oriented. All the languages which
13:19are there right now are object-oriented
13:21only. What is object oriented?
13:23>> Perception.
13:26>> Okay. Great. Yes. Next.
13:29>> Perception.
13:30>> Perception. What perception?
13:33>> How we see?
13:35>> So basically how we see something as an
13:37object. Great. Any other answers?
13:40Okay, very simple. There are three
13:41points which you have learned. One is
13:44this any this world whatever you see
13:46it's a collection of objects everything
13:48is an object including me including you
13:50also everything is a collection of
13:52objects and every object if you notice
13:54belongs to one category I belong to
13:56teacher category you belong to you're
13:58not a student anymore fresher category
14:00remove that from mind first you're not a
14:02student you're a fresher you are a you
14:04are you have graduated that is how I
14:06think I never see you people as a
14:08student I'll be very clear I have here I
14:11have I'm there over to serve one purpose
14:14to get you placed at any cost. At any
14:16cost but are you really ready to put
14:19that effort is the question you answer
14:21yourself. So I am here to place you as
14:24fast as possible and equally you should
14:27also put effort. So that is the only
14:29purpose. You in my eyes maybe you can
14:32think you are my student but I think you
14:35are a candidate who came out of college
14:38in this city where it's very expensive
14:41and you are here to hustle to get a job
14:44as soon as possible to make your dreams
14:46fulfilled. So let's work to that
14:48particular goal. Don't get distracted
14:50unnecessarily. Now itself I'm saying
14:53everyday motivational talks I'll not
14:55give. I'm saying right now I'm not such
14:57person who will come and give
14:58motivational talks. Don't you think if I
15:02motivate for 10 minutes I personally
15:05feel it is time waste. Why sir if you
15:07ask me in that 10 minutes I could have
15:09taught you a concept which can be asked
15:11in an interview. Are you understanding?
15:14And again, don't get me wrong. If you're
15:18expecting someone else to motivate, your
15:21mindset is weak. I'm repeating this. If
15:25you're expecting, sir, someone will
15:27motivate, I'll become motivated, then I
15:29will start. Which means already you have
15:32told to yourself, I'm weak. Please stop
15:35pretending all these things. So don't
15:38wait for others to motivate. Why should
15:40someone motivate you?
15:42So this is what you have done in your
15:44last four years of engineering
15:46motivation then only study. So enough no
15:50one is going to motivate have self
15:51motivation I should do that's it there
15:53is no uh what do you call reasons for
15:55giving that so please do it if it is
15:57required you should do it at any cost
15:59anyways coming back to the point so next
16:02every object belongs to a category is
16:04what we understood what is a category
16:06basically I belong to teacher you belong
16:08to fresher next this belongs to
16:10electronic gadget whatever it belongs to
16:13furniture so like the different
16:14categories you can categorize in Java
16:18Specifically that category we call it as
16:20class.
16:22Class is not real. It is imaginary. If
16:25you did not understand you want to
16:27construct a house. Basically there is a
16:30blueprint. Is it reality? No. It is just
16:33an imagination. Okay. Architect has
16:35thought. This can be the plot. Maybe 4
16:38BHK duplex. Just thought is thought only
16:42right? It is it is it real? No. It takes
16:448 months or 1 year to bring it to
16:48reality. Maybe in Bangalore if you want
16:50to do that at least three crores you
16:52require only building I'm saying land 1
16:5515 crores you require this is the
16:57reality especially in BTM core Mangala
17:01JP Nagar Jagar one square ft will touch
17:0530,000 if you don't know 30,000 is one
17:09square one square ft you know how much
17:12it comes if you want to construct a very
17:14good house at least they said 30 40 site
17:17you remember what do you mean by 30 40
17:2030 + 40 1 1200 square ft² you require in
17:24that case 8 9 crores just for land that
17:27is a reality where are we we should
17:30think are you understanding can we
17:33achieve it yes you should hustle a lot
17:36it is possible one day but when is that
17:38one day I don't know you you should
17:41answer for yourself are you
17:42understanding so anyways that is not the
17:46point so I was just speaking about
17:48something that whatever object you are
17:51able to see it belongs to class. Class
17:53is not real. It is just imaginary. But
17:55what is real? That house which you
17:57construct is real. The object is real.
18:00When I say real in reality in your
18:02computer, in your RAM, it is created.
18:05Some storage, some space is created. It
18:08is real. Are you understanding? Later
18:12you understood one most important point.
18:14Every object has something some
18:17properties name, age, gender, which
18:20technologies I teach. These are all my
18:22properties. I can also do something. I
18:25can teach, I can run, I can sing, I can
18:28dance. So different different actions
18:29also I can perform. But coming to Java's
18:32perspective, whatever I told has is
18:35taken care by variables or data types
18:38basically. So using data types, you can
18:40store the properties. Sir what about
18:43behavior methods don't use function
18:47function is not the terminology of Java
18:49we call the math method I think some
18:51glimpse might be given by your sasar
18:53correct so this was understood for you
18:56by Java that's it nothing extra you have
18:59learned and completely you focused on
19:01logic building problem solving arrays
19:04all those things but I'll be completely
19:07teaching you the theoretical part where
19:09in technical facetoface 100 cross
19:12questions they can ask you every
19:14question they ask you can answer that is
19:16my guarantee by the end of these Java
19:17classes so but one expectation from
19:20today I'll make it very clear so in my
19:24classes I will not tolerate people using
19:27mobile phones unnecessarily unless if
19:29anything is important you can take a
19:31picture I have no problem next if you
19:34want you can take notes when I say notes
19:37for example I'll teach something known
19:38as encapsulation let us assume sir
19:40encapsulation Sir please tell me what is
19:42a definition sir please tell me what is
19:44a spelling no in my class notes means
19:48important points maybe two three points
19:50that's it I will give you a descriptive
19:52comprehensive notes already printed
19:55notes is given for you people on the top
19:57of which whatever I speak in this class
20:00you want that also that also will be
20:02provided I'll tell you how exactly as
20:04days progresses so notes don't think too
20:07much about notes in my class you should
20:09only think about one
20:11understanding the concept. How will they
20:14ask in the interview? Why will they ask
20:16in the interview? Where is it used in
20:18the real world software application?
20:20That's it. So later recording is there,
20:23notes is there. You prepare for yourself
20:26in the class. Don't deviate yourself.
20:29Your friend did not understand asking
20:31you. No, no problem. After the class
20:34half an hour, I'll wait there itself.
20:35You can come and ask me any doubt. Are
20:38you understanding? in Java sir python
20:40dot go to that classroom understood so
20:43this is what I expect so let's continue
20:48and let's start a quick revision is
20:50required before me directly starting
20:52today's concept so I think probably some
20:55programs you might have solved data
20:57types introduction was given for you you
20:59remember so what is a data type
21:01according to you simple sir usually this
21:03world is not of binary your name my name
21:07my mobile number your height, your
21:09weight, is it in zeros and ones? No. But
21:12unfortunately, my computer cannot
21:15understand all these things. It can't
21:17understand my name. It can't it can't
21:20store my number. So, it can only store
21:22zeros and ones. My processor can process
21:25only zeros and ones. My RAM can store
21:28only zeros and ones. So, what to do?
21:30They understood we require a converter.
21:33In every programming language, there is
21:35a converter. So data type is a facility
21:38where it will convert the real world
21:40data into zeros and ones as simple as
21:42that. Are you understanding? So that is
21:45the purpose of data types. In every
21:47language data type is there. But in some
21:50languages like Python and JavaScript
21:53explicitly you will not mention int a
21:55equal to and all you will not say that
21:58is the syntax basically but data types
22:00will be there. Are you understanding? So
22:02anyways, let's start writing our first
22:05Java program today. Understand
22:07technically. So what I'll be doing is in
22:09my classes to teach Java, I'll be using
22:12Eclipse. I think you might also have
22:14been familiar with this. You can use
22:16Eclipse. You can use IntelliJ also if
22:19you want. Okay. But I'll be preferring
22:21Eclipse itself. So this is how the
22:23Eclipse looks like. I will show you how
22:25to set up the project also if you don't
22:27know. So quickly I'll just open my
22:31screen.
22:33Okay.
22:36Okay. So this is how the Eclipse
22:38interface looks like for a first time.
22:40All these things will not be there. I'll
22:42just remove everything. This is how
22:44blank it will be like. Okay. Step one.
22:46Can you see on the top? There is
22:47something as file. Click on the file.
22:50You can see new. When you see new, you
22:52can see Java project. Now sir, what is
22:54that Maven project? What is that spring?
22:56It's not for today. We'll keep it for
22:59later in project building sessions in
23:01your advanced Java. You'll get to know
23:04all those things. But for today, what is
23:06Java project? You need to understand
23:08very simple. It's a place where I can
23:10write my Java code. As simple as that.
23:12But some people might come for me and
23:14say, "Sir, I'm not able to see the Java
23:16project. There is a problem with my
23:18Eclipse." No problem. Sometimes the
23:20perspective might have been changed.
23:22There are two perspectives. One is Java,
23:25one is Java E. In Java double if I click
23:28on file and new obviously I'll not see
23:30Java project. So if you got the problem
23:33what you should do just go over here and
23:35click on Java project. So Java project
23:38that icon only I'm not able to see. Then
23:40what should I do for that? Go to window
23:43go to perspective and click on open
23:46perspective and you can get Java. Are
23:48you understanding here also you can get
23:50it. Anyways we are already in Java. It
23:51will not show. Next click on file new
23:55Java project. It will show you a pop-up.
23:59What is the name? For example, I'll say
24:01Java.
24:03Uh maybe I'll say what is the month for
24:05today. I'll say August. So I'll say Java
24:08August like this. Uh and I'll say new
24:10just for example. Next it is asking what
24:13JRE do we want? All those things are
24:15none of our business for today. Let's
24:17ignore it. So directly I'll click on
24:19finish. But wait module info on Java.
24:23You're able to see right? Never ticket.
24:25So keep it like that itself. Okay. So
24:27I'll just click on finish. So brand new
24:30Java project got created. Now once Java
24:33project is created, you should type you
24:35should start typing. So you need to type
24:36it in a class. So I'll just create a new
24:40class like this. And the name of the
24:41class today is your day one of Java
24:43class. So I'll say day one. And as I
24:45want main method, I'll say finish.
24:48This is how you can set up your Eclipse.
24:51Clear? Great. Now the moment I actually
24:55open this code, you can see one thing
24:57already. It is available. What is class?
25:00I hope all of you know it. Class is
25:02something which is imaginary. And let me
25:04tell you, every line of code in Java
25:08should compulsory be inside class. Are
25:11you understanding? One line outside
25:13class you can't write. I hope you're
25:16getting the point. Now 100 questions you
25:18might have. Sir, can we create more than
25:20one class? Can we create 100 classes?
25:22All those answers you will get it. Don't
25:24worry. Are you understanding? So what is
25:26the first rule? Every line of code
25:28should be inside a class itself. Outside
25:30you cannot write. This is the first rule
25:32of Java. Next, if you want your Java
25:36program to execute compulsory, there
25:38should be one method. What is that
25:40method? Main method. What is main
25:42method? Very simple. See if you notice
25:46public static void main string arcs.
25:50What is this public static void main
25:52string arcs? I just want to give a
25:54glimpse then we can start actually
25:55continuing. So let me close this
26:00observe.
26:02See I think probably this was the code
26:05when you have seen I think uh on the day
26:07of object orientation you remember. So
26:10there is something as class car. We have
26:13name, cost, mileage, start, accelerate,
26:17stop. Some methods are also there. Now,
26:20unfortunately, this code if I execute it
26:23will not work. Why? If you ask me in my
26:25computer, yes, there is my J JVM and all
26:29all those things also might happen, but
26:31especially JVM will tell you I cannot
26:33execute it because main method is not
26:37found. Now, why exactly is that problem?
26:39If you ask me, observe very carefully.
26:41See I have Windows operating system I
26:44also have something known as uh what do
26:46you call Mac OS at the same time I also
26:48have Linux operating system was it
26:50already taught for you earlier yes so
26:53I'll just give a glimpse again I don't
26:55want to go deeper because already you
26:56know every operating system if you
26:58notice definitely who is the boss of
27:01your computer operating system your RAM
27:04your hard disk your GPU your CPU
27:07whatever you name OS only will control
27:10it similar Clearly think about it. I
27:12will write one Java code. Where is it
27:15stored? Where is it stored? Inside RAM
27:18itself. Sir, I don't know what you are
27:20speaking about. I'll show you. Observe.
27:22See if I just search for something
27:24called as task manager.
27:28I hope everyone might have seen at least
27:30this once in a lifetime. This is only
27:32the virtual representation of your RAM.
27:35If you notice one thing, out of 32GB is
27:38the RAM. out of that 47% of the RAM is
27:42used by whom? By any desk, by eclipse,
27:45by chrome, by mirroring 360. So all the
27:48softwares are using my RAM currently.
27:51And somewhere I'll type my Java program.
27:53It is in Eclipse only, right? Where is
27:54Eclipse inside RAM? So, so what I'm
27:57trying to say is the Java program which
27:59I typed currently it is in my RAM. So
28:02who should give permission for the RAM?
28:03Operating system. Now operating system
28:06will not give anywhere it want. it'll
28:08give to main method. Are you
28:10understanding? So whatever you call your
28:12main method is the entry point of your
28:15Java program. Clear? So let me close
28:18this. Yes. So what I'm trying to say is
28:22for all the programming languages of
28:23this world main method is compulsory. Of
28:26course something like Python and
28:28JavaScript is exclusive for the main
28:31method is not required. Internally it
28:32will be already there. So the permission
28:34whichever is required is provided by
28:37something called as main method or main
28:40function. Are you understanding? Let's
28:42understand. Imagine in C programming if
28:45I want to print hello world already you
28:47know include std io. Something you'll
28:49say right and some void main you'll
28:51write and you'll say quickly print f
28:53hello world. And your teacher used to
28:56say void main compulsory. You never
28:58cross question why compulsory no answer.
29:01Why is it compulsory? Because my
29:04operating system should give permission
29:06for my program and that control of
29:09execution will always be given only for
29:12one function that is main function. Are
29:15you understanding? No problem. Even if
29:17you know all of this just think today is
29:19a revision class from tomorrow we'll go
29:21much deeper. Don't worry about it. So
29:24now this main function is exists right?
29:26That is the reason permission is given
29:28printing will happen on the screen. But
29:30same thing if I should write it in
29:32Python simply you'll say print that's it
29:35but same thing if I should write in Java
29:37observe carefully
29:40include and all I should not I'll just
29:41ignore it in Java first and foremost
29:45void main is compulsory but before void
29:48main something you should write already
29:49you know it so it is none other than
29:51public and static but why public and
29:54static might be the question let us
29:56understand in the easiest way possible
29:58now before understanding Learning public
30:00static to print something in Java you
30:03should understand something there are
30:05two things you should understand one is
30:07input one is output printing is an
30:10output thing right it is output so you
30:13should actually attach one pipe I think
30:15you might have learned that pipe
30:17technically is called as output stream
30:20what is that output stream and the name
30:22of that stream is system out so
30:26system.out out is an output string and
30:29ultimately what you want to do I want to
30:31print something so I should call
30:33system.out out output string and I'll
30:35say dot print or print ln or print f
30:39also you can say so print print ln print
30:42f there are three print statements what
30:45is the difference you'll understand next
30:47I want to print hello world I'll
30:48directly say clear next now observe
30:52control will be given but unfortunately
30:55I told you the most important rule in
30:56Java what is that without a class can
31:00you write this no so what is expectation
31:02if you ask me Java will not allow it
31:05expect something where is class so I'll
31:08write class demo opening closing
31:12understand one thing what do you mean by
31:14opening bracket and closing bracket this
31:16is the starting of the class this is the
31:18ending of the class technically this we
31:21call it as a block
31:23unfortunately in Python that block does
31:25not exist you'll use colon okay anyways
31:27ignore so void main opening closing
31:31understood so this is So we write now
31:34observe yes class is there main method
31:36is there it will work right? No it will
31:37not work because class is there but main
31:40method is not visible for your operating
31:43system. Are you understanding? So main
31:46method should definitely be public. You
31:49just think about it. Public means what?
31:51Forget about Java for the time. Public
31:53means what?
31:55>> Public transport. Public toilet.
31:57Basically everyone can access it.
32:01Public transportation is accessible by
32:03everyone right but unfortunately right
32:05now in Bangalore and Hyderabad it is not
32:07accessible by everyone only accessible
32:09by such people who can use it for free I
32:12hope you're understanding so today a
32:15person even I'll pay 50 rupees please
32:17give me seat no you'll not get it that
32:20is how the situation has happened but
32:21anyways what I'm trying to say is public
32:24is accessible by everyone and whatever
32:27public you're seeing over here also
32:29serves the same purpose public is for
32:32accessibility only. It's called as an
32:35access modifier
32:37which will help your Java to access this
32:40main anywhere in the Java project. Are
32:44you understanding? Anywhere in your
32:46entire Java project, you can access main
32:48method because it is public. It is
32:49available for everyone. Clear? But
32:53unfortunately, think about it very
32:55carefully. I want you to go back and
32:57understand that object orientation
32:59class.
33:00If you want to call a method, imagine I
33:03want to start the car. Tell me how did
33:05you start the car? I don't I'll put key
33:07and I'll start. No, that is not what I'm
33:09asking. I'm asking in Java, how do you
33:11start a car?
33:14>> First thing I'll create an object of the
33:16car. Then I'll say C1 is the reference.
33:20C1 dot start. You told you remember. But
33:24if you notice one thing, main is also
33:26method only. Start also was method only.
33:29Now the question is if main method
33:31should be called first create an object
33:33of demo which means if you really wanted
33:36to call main method what you should do
33:38I'll just go over here. I'll say let me
33:41create a brand new object of car.
33:45This is how you used to do earlier but
33:47this time it is not car over here. It is
33:49demo because demo class. So I'll just go
33:52and say new demo. Next for every object
33:56naming is compulsory. If you did not
33:58understand you people have names right.
34:01Why?
34:03Simply
34:05because I can access your data. I want
34:08to know your CGP. Your name your height.
34:10I'll access through your name. Object is
34:12there but no name. How will you access
34:14it? Name is compulsory. That name we
34:16call it as a reference. I will name it
34:19as D. and D is of type demo
34:24clear sir why are we saying this type
34:27and all you'll understand don't worry
34:28about it now object is ready can I call
34:31this method yes so I should just go and
34:34say d dot main
34:39now just think about it who should do
34:41all these things will os do all these
34:44things why operating system should do
34:47all those things is operating system a
34:48Java developer know then who should do
34:52you should only do it as a developer I
34:54should only do all these things but I
34:56don't want to do it so I want to
34:59completely skip this
35:02just to print one statement object
35:05already you people are frustrated this
35:06is so so complicated again object should
35:09be created main method should be called
35:12so how to skip all these things they
35:13told don't worry
35:16how to access this method without object
35:18creation I'll give you one keyword that
35:21keyword is none other than static. So of
35:24course without static it will not work.
35:26So compulsory static is should be used.
35:29So which means let me rewrite it. Main
35:31method should compulsory be public. It
35:34should be static and void main as it is.
35:38And now think about it. Simply open
35:40bracket close bracket you should not
35:42say. You should say something called as
35:44string arts. Now what is the string
35:46arts? I'll tell you don't worry. Clear?
35:49Why is it public?
35:52>> So that it can be accessible by
35:54everyone. Why is it static? So that I
35:56can call this method without object
35:59creation. That is the most important
36:00point. And void in English is nothing.
36:06Do you see this method returning
36:08anything for you? No. Do you see any
36:10return statement? I don't see anything.
36:12So it is not returning. Nothing means
36:14void. Name of the method is main. That
36:17is my main string arcs in RS. I'll teach
36:20you. Are you understanding? So this is
36:22how the main method got evolved. Simply
36:25by hearting public static void main is
36:27one set of people. Understanding the
36:30true meaning is another set of people.
36:32And such people who understand every
36:34word use case will become better
36:36engineers. As simple as that. People who
36:39just buyarted and become an engineer
36:41will still be there only floating. They
36:43will never a they will be never able to
36:45solve the real problems always someone
36:48should give them the task they should do
36:49it but I want you people to be in such a
36:52position where you should be able to
36:53give the tasks for others that is only
36:56possible if you know in and out of a
36:57software every word you should know it
37:00and I'll ensure you'll understand clear
37:03so anyways now public static void main
37:05everything is great now print statement
37:06will definitely be executed
37:09clear so this is the story of your main
37:12method
37:13So which means over here if I just go
37:16back
37:19if I want to execute anything definitely
37:21it should be public static void main
37:23next sometimes if main method is not
37:25there in your program you can use a
37:28shortcut what is that if you ask me just
37:30go and say main control space you'll get
37:33one shortcut you can say enter so I'll
37:36also explain you all the shortcuts that
37:38is used by Java developers clear so what
37:40is a shortcut if you ask me Always just
37:43go and say main name of the method you
37:44should know. Control space enter. Is
37:48this clear? That's it. Now you want to
37:51print something. Tell me how do you
37:52print something? Uh system dot very
37:55boring statement, right? So do one
37:57thing. Just go and say sis out. Sis out
38:00is the shortcut. Again control space
38:03enter.
38:04Clear. So let me show you uh show it for
38:07you people. So observe. So if I want any
38:11shortcut just go and say sy
38:14control space if you you'll get
38:15suggestions enter
38:18clear but then in your pycharm and all
38:20you'll get suggestions there itself
38:22inline suggestions all such options in
38:24eclipse you don't have understood so if
38:26you want to print anything you can just
38:28go and say hello to day one but oh sorry
38:33traditional way we need to do it so
38:35hello world only is the first program I
38:37want to print so I'll say hello world
38:39click clear after that I can start with
38:41the second thing so I'll say hello to
38:43day one
38:46any confusions of course very basic but
38:49very important why do you think people
38:51always teach hello world only at
38:53starting
38:55why
38:57it's the tradition okay I'll ask you a
38:59very simple question if anyone calls you
39:01what is the first word you speak
39:03>> why tradition
39:06>> I'll tell you the fact hello is the name
39:08of a I mean
39:11you know or you don't I don't know like
39:14you only I also saw in a so basically
39:17the person who actually invented the
39:18mobile I mean telephone back then he
39:21don't know what to speak with his wife
39:23he told hello from then it started to
39:25become a tradition today also hello so
39:28every time we speak with a person we are
39:31remembering her name hello anyways
39:33similarly like that for every program
39:35any language hello world is the first
39:37program tradition okay anyways
39:40So I hope this much clarity got it
39:42great. I think in the previous classes
39:45you might have done something like this
39:46int a equal to 100
39:49and then you'll just go and say
39:51system.out.print ln you'll say a. What
39:53is the answer 100? Obviously now the
39:55question is what is this int? It's a
39:58data type. But the question is is int
40:01the only option? No. You have something
40:03called as bite. Byte also will give the
40:06same output. But observe very carefully.
40:09I'll just go over here and say 128. The
40:12moment I say 128, it is not working.
40:15Some problem. It seems type mismatch.
40:17But same thing if I make it as int.
40:20Absolutely there is no problem. Why
40:24we'll understand. Don't worry.
40:26Similarly, for example, I'll just go
40:29over here and say 45.5
40:32and I'll just store it in a variable
40:34known as a. and a is of a type double.
40:37I'll say double. I will save it. I'll
40:40click on run button. No problem. But
40:4245.5 can be float also. I'll save it.
40:45I'll click on the run button. There is a
40:47problem. What is the problem?
40:50>> So some people are able to answer
40:52because they might have known Java. But
40:54many people have a question mark. So
40:56you're pretending you know data types
40:58but the reality is we don't know data
41:00types. We should go deeper and
41:03understand every inch of data type. Yes,
41:05it's a very simple silly concept but lot
41:07of MCQs will be asked. Predict the
41:10output. One more question I would like
41:12to ask you. Let me see whether you can
41:14answer it or not. I'll just go and say
41:16bite a 128 was a problem. Right? So I'll
41:19say 127 semicolon. Is it allowed? Yes,
41:22it is allowed. I'll click on run button.
41:25Now that is not the question. I'll just
41:27go and say a++
41:30again. I'll just go and say a++. Now
41:32tell me what is the answer.
41:35US.
41:35>> Huh?
41:36>> So some people are very clever already.
41:38They're answering correctly. Minus 127
41:40it says. Now why is it happening? Simply
41:43if you buy and put the right mark in the
41:45MCQs it doesn't help you what is
41:47happening internally. Let's go deeper.
41:50So the first concept for today is your
41:52data types and the interview questions
41:55they can ask you. Okay let's understand.
41:57So let me close Eclipse for the time
41:59being.
42:01Okay. First and foremost already you
42:04might have known that integer type data
42:06exist in this world. Your h is an
42:10integer value or real number.
42:13>> Integer only not real number. What is
42:16the difference between integer and real
42:17number?
42:20>> Why I'm asking this question? You know
42:22some people who comes from engineering
42:24background don't know number systems
42:26also. That is the reality in which we
42:28are living.
42:30Even many of you who are sitting over
42:32here still don't know very simple
42:35integer whole numbers means basically a
42:38number without decimal point is known as
42:40an integer value a decimal value are you
42:43understanding decimal means today what
42:45you and me are using right it's a
42:47decimal number system any number that we
42:49use will be between 0 and 9 only decimal
42:52number system are you understanding and
42:54integer decimal numbers numbers means a
42:57number without point that is inte
43:00integer category. So in Java we have
43:02four data types bite, short, int and
43:05long. Four data types. So these are four
43:08options. We'll understand. Similarly,
43:10real numbers means what? Which has a
43:12decimal point. Your height, your weight,
43:15your CGPA, there are two options. One is
43:18float, one is double. To store
43:20characters,
43:22we use a car data type. So we have car
43:25data type. Similarly, yes or no. In
43:28programming we call it as true or false
43:30we use boolean for others we don't have
43:33data types we have something called as
43:34built-in libraries basically so that
43:36you'll understand advanced Java classes
43:39how to use audio file in Java all those
43:41things clear this these are the eight
43:44data types in Java don't by heart
43:48whenever someone asks you no one will
43:49ask you by the way but how do you answer
43:52in Java there are eight data types to
43:55store integers we have four data types
43:57bite which occupies one bite short which
44:01occupies two bytes similarly int which
44:04occupies four bytes long which occupies
44:08eight bytes of memory now what exactly I
44:11meant by this memory I'll tell you this
44:13is how you should answer coming to real
44:14numbers in Java we have two options one
44:17is float one is double to store
44:19characters we have car data type to
44:21store boolean we have boolean data type
44:23this is how you should answer now let's
44:25start with the first cate category that
44:27is your integer category and first data
44:30type which is bite. Now what exactly do
44:33you mean by bite? I'll go to my Java
44:36program. I'll say bite A. When I say
44:38bite A, what happens? Back side. What
44:41happens? Simple. Now byte a means this
44:45is my RAM. Example 2 GB RAM. How many
44:48bytes are there in 2GB? 200 CR bytes.
44:54Giga means 10 ^ of 9. 10 ^ of 9 means
44:58100 cr. So 200 cr bytes are there. Now
45:02in this 200 core bytes I don't want
45:04anyone. I just want one bite. So when
45:08you say bite a in java one bite is given
45:11for you and tell me what do you mean by
45:13one bite? It's a combination of eight
45:16bits.
45:18Please keep your mobiles in silent in my
45:21classes. Okay. Anyways,
45:25so one bite is equivalent to 8 bits. So
45:27I'm just dividing it to eight bits. Now
45:30my question is in your entire RAM there
45:33are crows and cres of bits right but
45:36correctly how will you identify this is
45:38only your bite because you told a right
45:40that a will act like an identifier in
45:44your language variable. Are you
45:46understanding that a is the identifier?
45:48So when I say byte a in my entire
45:50program this bite only will be tell me
45:54imagine there are two rahuls in this
45:56class. I'll tell Rahul which Rahul
45:58should respond. Both will respond.
46:00Confusion. That's why I cannot create
46:03one more a in my Java program. Duplicate
46:05variable error you will get because
46:08confusion will happen. Right? I hope
46:09you're getting the point. But that is
46:11not the point. In the number system,
46:14negative infinity is the least negative
46:16number and positive in infinity is the
46:19highest positive number. Correct? Now,
46:21in one bite, there should be a
46:24threshold. There should be a capacity
46:26this much only I can store. How much is
46:28that?
46:30That is the question. In one liter water
46:32bottle only one liter only I can store.
46:351.1 liter also I can't store. What is
46:38the least possible thing in one liter?
46:41>> Negative one liter zero lit right?
46:44Basically similarly in one bite I can
46:47store one highest positive value. I can
46:50store one least negative value. What is
46:52that number? There is a simple formula
46:55which you should definitely not by
46:56heart. Okay. So n bits are there. The
46:59least negative number is minus 2 ^ of n
47:02minus one. The highest positive number
47:04is 2 ^ of n -1 minus one. Now tell me
47:08what is n over here? One by means 8
47:11bits. If I substitute that 8 bits 2 ^ of
47:167 - 2 ^ of 7 + 2 ^ of 7 - 1 which is
47:21nothing but 128 to 127 that is the
47:27reason my Java compiler did not allow me
47:30to store one value extra one value
47:33lesser.
47:35Are you understanding? So in the number
47:36line also if I show you what is the
47:38highest positive number I can store in
47:40bite 127. What is the least negative
47:43value minus 128. So let's see this in
47:46practical. So I'll just go over here.
47:50So I'll just go and say byte a is equal
47:53to 127. No problem. If I just go and say
47:56system.out.print ln absolutely I can see
47:59the output. But if I just make it as 128
48:04already you can see there is a red
48:05underline in Eclipse. If you see red
48:08underline this means there is a mistake
48:11already which has identified by the
48:13compiler. Forget about JVM. Compiler
48:16only told I cannot proceed because you
48:18have done a mistake. So if I save it if
48:20I click on the run button you can see
48:22sir what is this error? Can you read it?
48:25Definitely unresolved compilation
48:28problem. What is the problem? Type
48:30mismatch. Data type mismatch it seems.
48:33What do you mean by mismatch? LHS and
48:35RHS are not equal to each other. Why?
48:38Because cannot convert int to bite its.
48:41Now this is a statement which might be
48:43confusing. In the next few minutes
48:46you'll understand what is that clear?
48:48Okay sir. But if I make it as a negative
48:51value this is no problem. If I save it
48:54click on run button. Tell me what is one
48:57value lesser than minus 128
49:00minus 127
49:02- 129. Okay, good. So if I click on run
49:06button, not possible. Clear? So this is
49:08very very clear that bite has only one
49:11bite of memory. I can only store that
49:14much value. Clear? But what if I want to
49:17store more than 127 and less than minus
49:20128? There is another option for that
49:22also. So we have the second data type
49:25that is your short. Same thing. Now when
49:28it says short a this time it is not one
49:31bite double the bytes. How many bytes?
49:34Two bytes which means in my 200 crores
49:37of bytes correctly only two bytes is
49:39given for me. Two bytes means you know
49:4116 bits 2 into 8. These two bytes
49:45combined together is called as a. Now
49:48same formula if I apply I'll get a
49:50positive and negative value. Let's
49:52quickly see that also. Again, let's not
49:54go by the formulas and all. It's very
49:56simple. - 2 ^ 15 to the positive 2 ^ 15
50:00minus 1, which is nothing but some
50:0232,536.
50:05So, basically, it's negative sorry
50:0832,768
50:10to all the way till 32,767.
50:12See, no one is going to bother about
50:14what are these numbers, but you should
50:16be knowing. Clear? So, this is what is
50:19the value. Let's quickly execute this
50:21also and check it. So I'll just go over
50:23here
50:25and I'll say I want short and instead of
50:28minus 129 I'll say 32,000 767 is
50:32allowed. If I save it you can clearly
50:35notice one value extra is not allowed.
50:39You can see already same error you will
50:41get. But if I make it as a negative
50:44value no problem if I save it. If I
50:47click on the run button, you can see
50:49clear. Great. So sir, what if I want a
50:53better option that is a very frequently
50:56used option also that is none other than
50:59int. int is a commonly used integer data
51:03type anywhere. You'll understand why
51:06simple when I say int a what is the
51:08meaning of it? Double the bytes of last
51:10time four bytes will be given. Which
51:12means in my corres of bytes correctly
51:16four bytes are given for 4 into 8 32
51:20bits. So 32 bits put together is called
51:23as a and again if I put the same formula
51:26you'll get the certain value some 214
51:30crange you'll get. So you can clearly
51:33notice - 2 ^ of 31 to the positive 2 ^
51:38of 31 minus 1 which is nothing but 214
51:41cr change
51:43which means the highest positive value
51:45and the least negative numbers you got
51:46it I think I need now to type it and
51:49show you I hope you understood one value
51:52extra I cannot one value lesser I cannot
51:55I don't think so in any programs that
51:56you solve the values will be that
51:58extremely huge that is why we prefer int
52:02But what if I want to store 500 cr 1,000
52:06cr what should I do? There is a last
52:09option that is none other than long. So
52:12when I say long a 8 bytes is given for
52:15you which means if you notice in the
52:17corres and of bytes correctly 8 bytes is
52:19given and 8 into 8 is 64 bits. If I put
52:23that formula no need to calculate
52:24directly I'm showing you it's an
52:26extremely huge value.
52:29So 64 bits means uh almost uh count tens
52:33or tw uh sorry tens hundreds thousands
52:3610,000 like this you keep counting but
52:38not required extremely huge value are
52:41you understanding now you want me to
52:44type this I will type it so let's see
52:47how exactly this actually works in Java
52:50so I'll just go over here I'm I'm also
52:53human being itself I don't remember that
52:55number I'll just Google it okay so I'll
52:57just go and a long uh range in Java.
53:04So that number I'm just typing it over
53:06here.
53:11Okay. So I'll just go over here and say
53:14uh I'll say long a is equal to this is
53:17the highest positive value possible and
53:20I'll say system.out.print ln I'll say a.
53:24Now the question is sir why there is an
53:26error? Have you given correctly only? I
53:29have given correctly only. So if I save
53:32it up so carefully. If I click on run
53:34button, same error you'll get. This time
53:37I want you to read the error very
53:39carefully. Of course it's a compilation
53:42problem. I do understand. But what the
53:44literal
53:46remember what is this literal sir? In
53:49your language it is called as value.
53:52In computer science it is called as
53:53literal. The literal whatever number you
53:57gave is of type int is out of range. It
54:02seems one thing is very clear somewhat
54:05clue you are getting sir this is
54:06definitely more than 214 cr that is why
54:09it is saying int is out of range but why
54:12did that error come for my long is the
54:14question. The most important rule you
54:17should remember is any number that you
54:19type in Eclipse or Java. Basically any
54:21number automatically by default it is
54:25int only. I repeat it any number any
54:31integer number you type in Java by
54:34default it is int. By default it is int.
54:37Not bite not short not long it is int.
54:40Now don't you think the number which I
54:42gave is definitely outside the range of
54:44int only. Now I should tell to my
54:46compiler listen this is not int value
54:48I'm intended to do it is a long value at
54:52last I should go and say l are you
54:55understanding just a second
54:59uh what is the problem okay I think I
55:02have given a wrong number just a second
55:04yeah it's not one okay now you can see
55:07same problem only you will see so now I
55:09need to just go and say l are you
55:11understanding l means long now is it
55:13allowed This if I click on the run
55:15button you can see. So this is called as
55:20a prefix. Sorry it is called as a
55:22suffix. Are you understanding? Something
55:24which you give before is known as
55:25prefix. Something which you give after
55:27is called a suffix. Prefix. Prepaid
55:31means what? First pay and then use. Post
55:33paid means first use and then pay.
55:35Similarly prefix suffix. You can use
55:38small L also. No problem. It will also
55:40work
55:42but not preferred. Why? Look at that and
55:45tell me does it look like L? It looks
55:47like one. So that is the reason they
55:49told better use capital L. Any
55:52confusion? So the first point new thing
55:54that you have learned today is any
55:57integer number if you give in Java by
55:59default it is int. If you want long you
56:02should say L. Are you understanding? But
56:04sir for short and bite you did not say
56:06no. It is within the range of int only.
56:08Right? So no problem. Are you
56:10understanding? So this was your
56:12integers. So we have seen four types of
56:16data types especially for inteious bite
56:18short int long and their memory as well.
56:20What next up
56:25anyways this was already clear for us.
56:27Now I'm just showing some people in
56:29front of you and why am I showing this
56:32if you ask me? I want to write a program
56:34to store their ages.
56:37Now which data type is preferred?
56:40Integer category only. But in integer
56:42you have four types right? Which one?
56:45Int. But think about it very carefully.
56:48Now from today you should start thinking
56:50like a programmer like a developer from
56:53the company perspective from the cost
56:55perspective also.
56:58Remember very important statements I'll
57:00be making here and there. As a developer
57:03every bit matters. Forget about bytes.
57:06Every bit also matters. How effectively
57:10can you utilize the bits. The bytes is a
57:13very important thing for a developer.
57:15Which means you people are saying saying
57:17sir use int. I can use long also. I can
57:20use short also. But I would like to
57:22prefer bite. Why? Tell me what is the
57:26maximum age you want to live on this
57:28planet?
57:30>> 100 century. Wow. God bless you.
57:35So on an average statistically speaking
57:3885 is more 75 is average actually in
57:42India 75 to 80 you can think but extreme
57:46case you are in a city where every day
57:49you're getting fresh air you're eating
57:51organic fruits every day whatever lunch
57:54you have has a lot of protein so you're
57:57eating a very healthy food right every
57:59day 1 hour you do workout also so
58:01guaranteed 100 years correct
58:04So as a matter of fact definitely 100 if
58:08you take also
58:10world record is some 120 to 123. So 127
58:14is more than sufficient. So when you
58:16told int why did you say int I'll tell
58:18you because you told sir these many int
58:21we have used but if you think in a
58:23different perspective bite occupies one
58:25bite int o occupies four bytes don't you
58:29think three bytes extra you're wasting
58:31you are wasting and the three bytes may
58:34seem very simple sir see three bytes
58:37only no sir 200 cr bytes are there one
58:41user three bytes thousand users one lakh
58:43users one cr us users 100 crore users
58:47think scalability also you should think
58:49that is how you become a true engineer
58:51are you understanding three bits also
58:53matters so don't you think I can easily
58:56use for ages I can use a bite are you
58:59understanding next one more example for
59:03storing the salaries fresher average
59:05salary I'm saying I'll ask what is your
59:08salary and
59:11no one will throw money like this very
59:13important so basically what is an
59:14Average salary of a fresher if you ask
59:16me somewhere between 30,000 it can be
59:18more it can be less but average I'm
59:20speaking in India short is more than
59:23sufficient 30 to,000 it can store so I
59:25can use short so you can see based on
59:27use case I'm differentiating
59:30some people are not happy with our
59:32planet are create creating plans are
59:35creating different different
59:36technologies to go to some other planet
59:41people are not happy over here people
59:43are thinking in Next thousand years
59:45earth will become inhabitable.
59:48Mars is already inhabitable but they'll
59:50make it habitable. It seems by creating
59:52atmosphere by creating oceans. They are
59:54doing some experiments. So people wants
59:56to travel from earth to Mars. Some
59:59distance should be calculated. Now the
1:00:01distance probably will be in lacks of
1:00:03kilometers if not of kilometers. So int
1:00:07will be more than sufficient.
1:00:10Clear? If you want you can also go.
1:00:12Okay. But if I zoom out these planets,
1:00:14they belong to Milky Way galaxy. There
1:00:17there are millions of galaxies in our
1:00:19particular universe. The distance
1:00:21between galaxies will be in thousands
1:00:23lacks of crows kilometers. Probably I
1:00:27can use long.
1:00:29This is just an example. But what did
1:00:31you understand from this four four data
1:00:34type simply they did not give for
1:00:36utilization of memory efficiently. They
1:00:39have given four types. So depending upon
1:00:42situation various magnitude of data you
1:00:45might have seen right one is a very
1:00:47simple small number one is an extremely
1:00:49large number that we call it as various
1:00:52magnitude of the data for that you have
1:00:54four data types simply they did not give
1:00:56are you understanding so which situation
1:00:59suits you better use that data type
1:01:02clear always think from the memory
1:01:03perspective never waste memory
1:01:06understood anyways so I think this much
1:01:09clarity you got it
1:01:11But I have a very important question to
1:01:12ask you. Imagine I'll say bite a equal
1:01:16to 24.
1:01:1824 is your age. Maybe next year or the
1:01:21next year you'll get it. Now 24 if I
1:01:23type in my Eclipse in my RAM directly 24
1:01:26will be stored.
1:01:28>> No. Right. This is high level. High
1:01:31level is converted into byte code. Byte
1:01:33code is converted into zeros and ones.
1:01:35That zeros and ones is stored in the
1:01:37RAM. My question is how is the 24
1:01:40converted into zeros and ones is the
1:01:42question.
1:01:44>> Very simple. So whatever 24 you are able
1:01:47to see in how many bytes are you
1:01:49storing?
1:01:51>> Eight bits or one bite. Now in this one
1:01:53by eight bits are there. What is each
1:01:56bit? Either zero or one. Now how do you
1:01:59calculate? It's very simple. See
1:02:02internally all these things will happen.
1:02:03One bite I'm showing you as eight bits.
1:02:06So first I'll take the 24.
1:02:09There is something called as base two
1:02:11format. What is this base two format if
1:02:13you ask me? Take the number and divide
1:02:15with the two. As long as you get the
1:02:17remainder as one. If you did not
1:02:19understand I'll take 24. I'll divide
1:02:22this 24 with two. How many times? 12. So
1:02:25next again I'll divide it. What is the
1:02:26remainder by the way? 0. Again I'll
1:02:28divide. What is the remainder? 0. Again
1:02:31I'll divide. What is the remainder? 0
1:02:33only. Again I'll divide. This time 2 1
1:02:36are is two and remainder is going to be
1:02:38one. When the original number becomes
1:02:40one, you should stop the division. Now
1:02:43if you notice from bottom to top if you
1:02:46take that is nothing but 1 1 0 0. I will
1:02:49put it over here for you people that 1 1
1:02:520 0 is the binary of 24.
1:02:57Uh okay, one more zero. Oh, that's it.
1:02:59So 1 1 0 0. But think about it. How many
1:03:02bits I got? Five
1:03:04>> five bits. How many bits in one bite you
1:03:07have?
1:03:08>> Eight bits. So all these things I'll put
1:03:10it over here. But that extra three bits
1:03:12are nothing but your zeros.
1:03:15Are you understanding? So this is how
1:03:17for you it is 24. But how RAM looks at
1:03:20it? 0 0 0 1 1 0 0 0.
1:03:23So computers will only store this not
1:03:26this. But sir, when I'm printing I'll
1:03:30get 24 only. Then what happens? Again
1:03:32the same zeros and ones will get
1:03:33converted into 20 internally it will
1:03:36happen. See why I'm speaking all these
1:03:39things you know no one will teach you
1:03:40all these things but these are the
1:03:43fundamentals you should learn because
1:03:45again and again will you learn all these
1:03:47things no only once you will learn so
1:03:49you should focus on larger things right
1:03:51now but since the background that you
1:03:54come from the colleges amazing colleges
1:03:58right so unfortunately we should again
1:04:00start the foundation otherwise by now we
1:04:03could have started greater technologies
1:04:04but anyways no problem we can quickly
1:04:06complete all these things any confusion
1:04:09great you might ask me a question sir
1:04:12ask RAM to give only five bits no it
1:04:15will not give because the minimum memory
1:04:19that that can be given for you is one
1:04:21bite half bite and all it will not give
1:04:23you okay full ticket only half ticket
1:04:25and all that option is not there so one
1:04:28bite is the minimum memory so I will
1:04:30obviously get eight bits that extra
1:04:32spaces will be zeros
1:04:34but if you carefully observe sir this I
1:04:36understood
1:04:38There is something called as most
1:04:40significant bit. Observe carefully most
1:04:42significant bit. What is this zero? If
1:04:45it is zero, you should understand it's a
1:04:48positive value. It's a positive value.
1:04:51But if it is one, it's a negative value.
1:04:55Now on this note, what is minus4?
1:05:02Huh? 1 0 0 0 1 1 1 0 0 0 Wow it doesn't
1:05:08work like that just I'll substitute that
1:05:100 with one it is minus4 then you and me
1:05:13no need to be here itself it's not like
1:05:16that there is a separate calculation for
1:05:18that also already existing base to
1:05:20format you have right we need to
1:05:22actually add a two's complement of it so
1:05:25what is this all things observe what is
1:05:28positive 24 binary 0 0 1 1 0 0 0 don't I
1:05:32heart. Okay. So basically 0 0 0 0 1 1 0
1:05:360 0. What is two's complement? If you
1:05:39ask me first you should understand what
1:05:41is one's complement. Basically if you
1:05:43want to know the second part first part
1:05:45is important. Bahubali one after that
1:05:48only bahubali 2 pushp one after that
1:05:50only pushpa two. Like the different
1:05:52different things you have for first let
1:05:54us understand what is one's complement.
1:05:56Okay what is one compliment? Very
1:05:58simple. You have all these bits. Flip
1:06:02it. Flip it in the sense 0 will become
1:06:05one. One will become zero. So which
1:06:07means 1 1 1 0 0 1 1. That is 1's
1:06:12complement. What is 2's complement? Plus
1:06:14one. I should add
1:06:17just add + one. Huh. Now tell me what is
1:06:191 + 1?
1:06:21>> Two is a wrong answer.
1:06:23This is not normal mathematics. It's
1:06:26binary maths.
1:06:28Now again should I teach binary maths?
1:06:31It's very simple. Remember one simple
1:06:33rule. Whenever it comes to binary
1:06:36addition, only four things you should
1:06:38remember. Okay? What if I add one? I
1:06:42mean, let's start from absolute scratch.
1:06:450 + 0. That is one uh formation. Next 0
1:06:52+ 1. Next 1 + 0. Next 1 + 1. These are
1:06:56the only combinations in two digits. 0 +
1:07:000 is 0. 0 + 1 is 1. 1 + 0 is not 1. It
1:07:06is 1. Oh, sorry. My bad. My bad. My bad.
1:07:10Sorry. So, basically over here 0 + 1 is
1:07:131. And 1 + 0 is also 1. But 1 + 1 is not
1:07:17two. It is actually
1:07:23see listen.
1:07:261 + 1 is 1 and 0 over here. Basically
1:07:30two you will not get. I hope you're
1:07:32understanding. So basically 1 + 1 is 1
1:07:360. Don't read it as 10. It is not 10. It
1:07:40is 1 0 only. Are you understanding? So
1:07:43this table if you remember it is very
1:07:44very easy for you. 0 0 means always 0. 0
1:07:47with 1 is always 1 and 1 + 1 is always 1
1:07:510. This you remember. Okay. Keeping this
1:07:53in the thing. Let us add it right now.
1:07:56What is 1 + 1? 1 1 0. Like how you do
1:07:59normal mathematics. Take 1 and over here
1:08:01it is 0. Carry is 1. Again what is 1 +
1:08:031? Uh 1 0. Again what is 1 + 1? 1 0. Now
1:08:08what is 1 + 0? 1. So I'll keep it as it
1:08:10is. Next. If you notice 0 1 1. So if I
1:08:14put it over here, this is your
1:08:184. If you notice one thing, what is the
1:08:20most significant bit? one which is a
1:08:23negative number. Now why did I teach you
1:08:26this if you ask me? No one will ask you
1:08:28in the interview but you as an engineer,
1:08:30as a software engineer, you should know
1:08:32a positive number how it is stored. A
1:08:34negative number how it is stored. Are
1:08:37you understanding? This is your version.
1:08:40This is RAM version, computer version.
1:08:43Clear? So this is what I just wanted to
1:08:46explain. So that's it. Any confusions?
1:08:49Great.
1:08:51Next, real number category. So in this
1:08:55world you have already seen whole
1:08:58basically integer numbers. But now you
1:09:00can also understand in this world
1:09:03integers only does not exist. Real
1:09:05numbers also exist. Now all these real
1:09:08numbers which you are able to see in
1:09:09front of you.
1:09:11Okay. Anyways no issues. They can be
1:09:14stored in two data types. One is float,
1:09:16one is double. Let's start by
1:09:18understanding what is this float.
1:09:21Float means floating on the ocean not
1:09:25like that floating point shortcut is
1:09:28float understood float means don't think
1:09:30that float so floating point is the full
1:09:33form shortcut is float whichever has a
1:09:35decimal point now the question is I'll
1:09:38say float a what is the meaning of it
1:09:40simple in my RAM four bytes will be
1:09:43given for understood so this is my RAM
1:09:46and corres of bytes are there already
1:09:48you know it so four bytes put together
1:09:50is called as a now sir what is the range
1:09:54like how you have for integers should we
1:09:57calculate that not required so I'll
1:09:59directly show you the range this is the
1:10:01range minus 3.4 10 ^ of 38 to the
1:10:06positive 3.4 4 into 10 ^ of 30 extremely
1:10:09large one but in some mathematics
1:10:13you might have seen E also what is E
1:10:15exponent sir how did we get this tell me
1:10:18the formula not required because
1:10:21remember one thing how do you store
1:10:24integers inside your RAM which format
1:10:28base 2 format
1:10:31this is for integers
1:10:36now what about This float and double if
1:10:38you ask me they use something called as
1:10:41Ile E format
1:10:45are you understanding IL E format
1:10:48now when I say it E your college will
1:10:50come into your brain sir we had some ILE
1:10:53E conference IL E projects so definitely
1:10:57my guide told E guidance only I should
1:11:00follow even if margin little bit also
1:11:03let's go and get one more copy senseless
1:11:06Yes to be honest has it given any value
1:11:09for you? I'm just asking seriously okay
1:11:11I don't no comments so what I'm trying
1:11:15to say is whatever inteious you have
1:11:17seen which format they use base to
1:11:19format what about this float and double
1:11:21if you ask me i format now observe one
1:11:23thing formula is not required range also
1:11:26no need to remember this is about all
1:11:28about your float let me speak about
1:11:30double right now sorry
1:11:33online students
1:11:43Anyways
1:11:44speaking about double double the memory
1:11:47eight bytes you'll get and directly I'm
1:11:49showing you in 200 course of bite
1:11:51correctly 8 bits if I take so extremely
1:11:54huge range if you notice minus 1.7 into
1:11:5810 ^ of 308
1:12:00don't go by 1.7 go by the power
1:12:03extremely extremely huge range. This
1:12:05also uses it. Now the question is float
1:12:09also can store extremely large value.
1:12:11Double also can store extremely large
1:12:13value. Now when to use what is the
1:12:17question for inteious? You clearly
1:12:19understood when to use what. But what
1:12:20about float and double is the question.
1:12:22For that one simple analogy. What is
1:12:25your percentage?
1:12:28No in percentage have you calculated
1:12:32>> 80
1:12:33>> 70 something 70.2
1:12:37>> Okay. What is your percentage?
1:12:41>> 80 back seat white shirt
1:12:45>> 70.1
1:12:46yellow shirt back seat huh you
1:12:52>> in percentage 95
1:12:56no idea. Oh, you people only know CGPS.
1:12:59Okay. Okay. But in my days we are having
1:13:02percentages basically. So the decision
1:13:06between float and double when to use
1:13:08what? I'll tell you. It is all for one
1:13:11word. Precision. What is that?
1:13:13Precision. What is this precision? Sir,
1:13:15if you ask me. Imagine I'll ask
1:13:17percentage. Unfortunately, we're taking
1:13:19CGPS
1:13:22online students. What is the problem?
1:13:26Okay. Anyways, so
1:13:29one student will say 65 is my
1:13:31percentage. One more student will say my
1:13:33percentage is 65.2. One more person will
1:13:36say my percentage is 65.2836
1:13:40so and so forth. Now if I ask you who is
1:13:43more precise
1:13:46last student is more precise. How can
1:13:49you say is more precise? Because low
1:13:52many decimal points if you see more
1:13:54precise more accurate.
1:13:56Still if you did not understand what is
1:13:58this precision today if you open rapido
1:14:01or Uber or any application which
1:14:03requires maps two options it will give
1:14:06you do you want to give precise location
1:14:08or approximate location. What is the
1:14:11difference?
1:14:13>> Approximate means 100 m radius it will
1:14:16provide not exact location. Precise
1:14:19means with latitude and longitude
1:14:21correct little pin and it will give you
1:14:23precise means more detailed. So over
1:14:26here the last student is more detailed
1:14:29more memory is required. So use double
1:14:32less precision use float. Are you
1:14:36understanding? So the choice between
1:14:38float and double is up to four decimal
1:14:41points. If you want use float more than
1:14:44four decimal points if you want use
1:14:46double. So there is a difference are you
1:14:49understanding? But in most of the
1:14:51situations we'll be using float and we
1:14:53call it a single precision that is
1:14:55double the precision. Okay. So let's try
1:14:58to type this as well as a program. Just
1:15:02a second.
1:15:44Anyways, some internet issue. No issues.
1:15:47Let's continue.
1:15:49So, I'll just go and open my editor
1:15:53and I'll just go and say for example
1:15:5545.5
1:15:57I want to store. Let us assume I want to
1:16:00store in a variable a and what is the
1:16:02type of A? If you ask me double and I'll
1:16:04just go to the next line. I'll say
1:16:05system.out.tprint ln. I'll print a. I
1:16:08will save it. I'll click on the run
1:16:10button. You can see it is absolutely
1:16:13printing as per our expectation. But
1:16:15don't you think this small value can be
1:16:17stored in float also. So I'll just go
1:16:19and say float. But the moment I do this,
1:16:21there is an error. What is an error? If
1:16:24you notice, if you look at the error,
1:16:26you can answer it. Again, same type of
1:16:29error you have seen just before. Type
1:16:32mismatch cannot convert from double to
1:16:35float. Which means what is the meaning
1:16:38of it? Any real number in Java by
1:16:41default it is double. Any integer number
1:16:45in Java by default it is int. But sir I
1:16:48want it to be treated as float. Do one
1:16:51thing go and say you are float. F you
1:16:54should say compulsory. So there is a
1:16:56reason for it. So if I click on the run
1:16:58button you can see. So at any given
1:17:01point in Java if you want to write float
1:17:03value compulsory you should do this
1:17:06clear any confusions great so that's it
1:17:10this is all about your double and float
1:17:11so you should just know when to use what
1:17:14clear okay next you also have something
1:17:17called as true or false it's very simple
1:17:20I'll just go and say true means yes it
1:17:23is true I'll just go and say I want to
1:17:25store it in a variable it is of type
1:17:27boolean boolean means true or false. So
1:17:30I'll just go and say system.out.print ln
1:17:32I'll say a. Now obviously what is
1:17:35output? True. If I want it can be false
1:17:38also. If I save it I can click on the
1:17:41run button. It is false. Any confusion?
1:17:44Now the question is what is the size of
1:17:47boolean?
1:17:51>> Size of bite is one bite. Short is two
1:17:53bytes. Int is four bytes. Long is four
1:17:56by eight bytes. Next float is four
1:17:58bytes, double is eight bytes. What about
1:18:01boolean?
1:18:02>> Depends on the
1:18:03>> Now you can say one bite because only
1:18:05true and false. No, it's not like that.
1:18:07The size of boolean is undetermined in
1:18:10Java. It depends upon the operating
1:18:12system or it depends upon the JVM which
1:18:15you are using. Basically platform
1:18:17dependent.
1:18:19So boolean size is not determined.
1:18:21Clear? So it changes from OS to OS.
1:18:24Maybe in Windows it is one bite. Maybe
1:18:26in Mac OS it can be two bytes. Size is
1:18:28not determined. It keeps on varying.
1:18:30Clear? Great. Last but not least, the
1:18:34final data type is your character data
1:18:37type. One of the most important data
1:18:39type you should know. If you are someone
1:18:42strings started for any batch
1:18:45programming on strings not yet started
1:18:47for some people it has started. If you
1:18:50want to solve any program on strings,
1:18:53the next 10 minutes what I'm going to
1:18:54speak is very very very important
1:18:56because it is not just concept it is
1:18:59thinking also. Why does we actually use
1:19:02all these things today? So please make
1:19:04sure you are understanding extremely
1:19:07important. Observe
1:19:10your perspective only will change.
1:19:13Now of course that 45.5 already that you
1:19:17have understood. Let us ignore that for
1:19:18the time being.
1:19:23Okay. Observe. What do you mean by
1:19:25character? According to you,
1:19:28these are all characters only. Whatever
1:19:31you can see on your keyboard,
1:19:34there are three types. Alphabetical
1:19:37characters, numerical characters,
1:19:39special characters. These are only three
1:19:41categories. So any character that you
1:19:43can see why do they exist on my keyboard
1:19:47today? Why not some other characters?
1:19:49You might be having a question. Why
1:19:50don't I have Telugu, Canada, Hindi,
1:19:52Mallayalam? Why only English? So many
1:19:55questions are there. The next 10 minutes
1:19:57is the answer for that. Absa. See, let
1:19:59us imagine a hypothetical situation.
1:20:02Just a second.
1:20:08Okay, a hypothetical situation where you
1:20:12and me should speak with each other. No
1:20:15Canada, no Telugu, no Hindi, no Malanam.
1:20:17Only one language exists in this world
1:20:19that is English. But unfortunately 26
1:20:23alphabets are not there. How many
1:20:25alphabets are there? Alphabets I'm
1:20:27saying it as symbols. Only four symbols
1:20:30are there. A B C D. anything I should
1:20:33speak with you in ABCD only I should
1:20:35speak A B C D F E G something like that.
1:20:38So E is not there by the way only in
1:20:40four letters I should speak. Now the
1:20:42question is this four symbols I and you
1:20:46can speak but I want to store it in the
1:20:48computer. How will you store? Can my RAM
1:20:51understand A? No. B C D no don't you
1:20:55think a binary version should be there
1:20:57for that? Now if you notice for A I will
1:21:00only think what value can I give? I will
1:21:02only decide I will say for a if anyone
1:21:05types a on the keyboard it should be
1:21:07stored in the RAM. So what I will do is
1:21:09in my RAM I know ABCD can't be stored.
1:21:13So I will take a decision if anyone
1:21:15types ABCD I will ensure the zero and
1:21:18one version of it is stored. What is
1:21:20that if you ask me? Let me assign some
1:21:23binary code for it. For A the code is 0
1:21:270. For B it is 0 1. I will only decide
1:21:31it. Next for C it is 1 0. For D it is 1
1:21:34one. Do you agree with me? Which means I
1:21:37will type D but for my RAM it is 1 one.
1:21:40I will type A but for my RAM it is 0 0.
1:21:44Understand? [music]
1:21:45Understanding? Okay. But let us assume
1:21:48ears evolved. Four letters not
1:21:51sufficient. We need to communicate
1:21:53better. Let us assume the number of
1:21:55symbols doubled.
1:21:57E F G H also came. But my question is
1:22:02can I use any binary number of twodigit
1:22:05combination? Yes or no? I cannot because
1:22:08already I have lost the combinations
1:22:10completed. Right? So what should I do?
1:22:13Can I increase the length of this code?
1:22:15Yes. So what I will do is I'll make
1:22:18everything as a three-digit code over
1:22:19here. I'll make I'll just add a zero.
1:22:22Just a situation. Okay. Now can you tell
1:22:25me what is the first I mean what is the
1:22:27next piece of code? Huh? Very simple. 1
1:22:290 0. Next 1 0 1. Next 1 1 1 0. Last but
1:22:35not least 1 1.
1:22:37Like this it started to evolve but again
1:22:40eight symbols not sufficient. Number of
1:22:42symbols doubled. This time 16 symbols
1:22:45are there. Can you tell me what should
1:22:48be the symbol one?
1:22:50>> Very simple. Three-digit combination not
1:22:53sufficient. I'll just increase the
1:22:55length of the code. This time the new
1:22:57set of permutation and combination is 1
1:23:000 0 all the way till 1 one. Again if it
1:23:04doubles I hope you got the story clear.
1:23:08So this is how it got evolved like this.
1:23:11Whatever alphabets or symbols you are
1:23:14able to see how many such symbols are
1:23:16there is the question. So let us
1:23:19understand one most important thing. How
1:23:22did I decide two? Next, the length
1:23:24should be four. The length should be
1:23:26three. How did I decide? Very simple.
1:23:28There is a simple formula. Imagine four
1:23:30symbols are there. What was the length
1:23:33of the code? Two. How did you decide?
1:23:36There is a formula. Very simple. So the
1:23:39number of symbols four. How to write it?
1:23:422 to the power 2 to the^ of two. So I
1:23:46can write it as 2 to the^ of two. So
1:23:48which means that four is nothing but 2 ^
1:23:51of two. That power is two, right? That
1:23:53is why length was two. Clear? That is
1:23:56very important to understand. Okay?
1:23:58Next, number of symbols doubled. Now
1:24:00tell me what is the length? Eight.
1:24:03Sorry, the number of symbols are eight.
1:24:05What is the length? Three. How did you
1:24:07decide? Simple. Eight can be written as
1:24:102 ^ of 3.
1:24:13Next, we had something called as 16
1:24:15symbols. What was the length? Four. How?
1:24:18Simple. 16 can be written as 2 ^ of 4
1:24:22which means can you tell me if I give
1:24:25you number of symbols can you predict
1:24:27and tell me what could be the length
1:24:29that number how can I write it in the 2
1:24:31to the power of this much clarity got it
1:24:34let's continue the story now of course
1:24:36that you understood there is one flag
1:24:39which I'm trying to show you in front of
1:24:41you which is that flag America one of
1:24:44the greatest and most futuristic country
1:24:48in the world is what people treat today
1:24:51I don't know the story but today also
1:24:52same story only but already some
1:24:54negative impact has been started on this
1:24:56country which entire world is suffering
1:25:00today if you don't know today if you
1:25:04just open the gold price it have been
1:25:06skyrocketed like anything and you will
1:25:08think that a gold means it will increase
1:25:11there is a reason for it also and if you
1:25:13don't know America is the reason are you
1:25:16understanding So how America is the
1:25:18reason not directly but indirectly.
1:25:21If a war situation happens remember one
1:25:24thing whenever war situation happens
1:25:27entire world will go through
1:25:29uncertaintity. What do I mean by
1:25:31uncertaintity? Stability will not be
1:25:33there in the economy. What do you mean
1:25:35by this if you ask me? Simple as simple
1:25:38as stopping straight of harness. What is
1:25:41the straight of harness? Usually
1:25:4480 to 90% of the crude oil supply for
1:25:48this entire world happens through that
1:25:50straight off harmas. Now what is this
1:25:53crude oil today? Petrol, LPG, gas,
1:25:56diesel, all these things if you are
1:25:58using that is a byproduct of a fossil
1:26:01fuel refine refinement. Now if that
1:26:03crude oil supply is not there for this
1:26:05world that is why LPG gas in Bangalore
1:26:08which was 845 was paying last 3 months
1:26:10back today it is 970
1:26:13are you understanding but in your hope
1:26:16now it'll be even more costlier actually
1:26:18in urban cities actually the cost will
1:26:20be less petrol in Bangalore just 3 to 7
1:26:25I mean 3 to 5 months back it was 102
1:26:28rupees today 111 rupees are you
1:26:32understanding
1:26:33in your cities three entire three cities
1:26:35already will be 120 or 122 just go and
1:26:38check. So that is how the prices will
1:26:40get impacted.
1:26:42Are you understanding? Why sir prices
1:26:44will increase? Just think about it. If
1:26:47petrol prices increases, diesel prices
1:26:50increases, logistic cost also will
1:26:52increase. The truck which will actually
1:26:54deliver from one point to another, their
1:26:56cost will increase automatically. Goods
1:26:58cost also will increase. Who will pay it
1:27:01ultimately? Consumer only should pay it.
1:27:03No loss for the companies. At the end,
1:27:07consumer only will suffer. The whoever
1:27:10is going to use that product, purchase
1:27:12at last only will suffer. Which means
1:27:15today if some two countries are fighting
1:27:17with each other, leaders have no problem
1:27:20at all. They will live their lavish
1:27:22life. But who will suffer? The people of
1:27:24that country will suffer. And this they
1:27:28don't understand
1:27:29because money is everything right. So
1:27:32that is how the people live. But anyways
1:27:35long back like how today it is trying to
1:27:38dominate. It is pretending it is
1:27:40dominating this world but not. Okay. So
1:27:42there are many dominating countries for
1:27:44example China, Russia so many dominating
1:27:47countries are equal. Of course India
1:27:49also but comparatively the nuclear
1:27:52powers the nuclear weapons missiles
1:27:55these are the comparisons they do
1:27:57usually one of the strongest country
1:27:59America Russia and China and India now
1:28:03they this American president you know
1:28:06so-called Donald Trump he wants to
1:28:07dominate this world by showing that Iran
1:28:10has is in my control but nothing over
1:28:13there so because of two countries
1:28:16egoistic mindset
1:28:18entire world is suffering today. Are you
1:28:20understanding? Now long back in the year
1:28:251990s, 1940s, 1950s, same dominance they
1:28:29wanted to show.
1:28:31What there was one country called as
1:28:33Japan, I hope you know it. America went
1:28:36and told whatever I said you should
1:28:37listen, they said get lost. Okay, no
1:28:40problem. They just throw uh two atom
1:28:43bombs on Hiroshima and Nagasaki. Then
1:28:46the entire world witnessed the true
1:28:50disaster that can happen with an atom
1:28:51bomb. Countries got collapsed. They
1:28:54should again start from scratch. Civiliz
1:28:57civilization got vanished. Are you
1:28:59understanding? Then they treated oh
1:29:02America means we should be a bit careful
1:29:05otherwise same situation will happen.
1:29:07Then America started to dominate this
1:29:09world. This world should only follow one
1:29:11currency, one language, dollar, English.
1:29:16And today even today
1:29:1890% of the transactions that India does
1:29:21with other countries in trade is in
1:29:23dollars only. We buy crude in dollars.
1:29:25We buy gold in dollars. Rupee keeps
1:29:28falling today. Why rupees in alltime
1:29:30high? It is not a good thing. 96 rupees
1:29:3397 rupees. Sooner it will hit 100 rupees
1:29:36also. Worst thing. But 30 40 years back
1:29:40rupee was 30 rupees. 40 rupees. Uh again
1:29:43is the dollar. But today but other
1:29:46countries they are actually becoming
1:29:48better like yan Chinese currencies
1:29:51Russian currencies and all. So always
1:29:53remember a country can only grow if we
1:29:55are net exporter not importer. Are you
1:29:59understanding? So what I'm trying to say
1:30:00is this country so-called America wanted
1:30:03to dominate this world. They told
1:30:05English is the language for this world.
1:30:07That's why I'm speaking in English.
1:30:09You're listening in English. Your
1:30:11interview also will happen in English
1:30:12only.
1:30:14If that could have been not happened
1:30:15maybe I could have taught you in Telugu,
1:30:17Canada or any other regional Indian
1:30:19language or maybe Hindi but
1:30:22unfortunately companies don't accept it
1:30:24right so since you are in India you
1:30:27should take interview in Hindi they'll
1:30:28say get lost are you understanding so
1:30:30all those patriotism we can't show for
1:30:33our language because the clients the
1:30:35projects will be other countries people
1:30:37so unfortunately interview will happen
1:30:39in English only whether you like it or
1:30:41you don't like
1:30:43So you should only adjust for that. So
1:30:45that is what they have also decided that
1:30:47is why today your default language of
1:30:50your mobile phone is English keyboard
1:30:52has English keyboard. So everything is
1:30:54English only right including the brand
1:30:56name that you see blue star everything
1:30:58is dominated but back then if you if we
1:31:01have dominated the world maybe
1:31:03everywhere Hindi you might have seen
1:31:04maybe Canada or Telugu or whatever but
1:31:07that was not the situation. So what I'm
1:31:09trying to say is America told on a
1:31:12keyboard whatever is required to
1:31:14communicate with a computer in total you
1:31:17require some numerical characters some
1:31:20alphabetical characters and some special
1:31:23characters. How many total symbols if
1:31:26you ask me 128 symbols are sufficient.
1:31:29That is what they gave the conclusion
1:31:31and they told this 128 symbols include 0
1:31:36to 9 some 10 digits. Next small A to
1:31:40small Z 26. Next capital A to capital Z
1:31:44one more 26 some special characters like
1:31:47that if you add everything 128 symbols
1:31:50you will find are you understanding and
1:31:53this 128 symbols what you are able to
1:31:55see can you just predict what will be
1:31:59the length of the code binary code I'm
1:32:02asking you huh what is the length of the
1:32:06first symbol
1:32:08uh seventh symbol 128th symbol Just now
1:32:12I told you right 128 if you have can you
1:32:15calculate the length how how can I write
1:32:18128 in the power of two simple so what
1:32:21I'll be doing is number of symbols are
1:32:24128 how can I write 128 2 to the^ of 7
1:32:29so will be the length of the code or not
1:32:32on that note can you predict what will
1:32:34be the first code
1:32:36>> seven zeros what will be the last code
1:32:39seven ones in between the combinations.
1:32:42So what I'm trying to say is symbol one
1:32:45is 7 zeros which I'm trying to show you
1:32:47right now
1:32:49like that symbol two is 6 zeros 1 next
1:32:53five zeros 1 zero like that somewhere a
1:32:5865
1:33:00version of zeros and ones you'll get b
1:33:0366 like that small a 97 like that you'll
1:33:08get all the characters are you
1:33:10understanding sir can you Show all this
1:33:12particular thing. Of course, last one is
1:33:14one one 7 ones. These all 128 symbols
1:33:18are these guys only. If you notice few
1:33:22things you ignore. If you start directly
1:33:24from here space, exclamatory, quote,
1:33:28hash, dollar, percentage, all these
1:33:31symbols you know. Next 0 to 9 colon
1:33:34semicolon less than equal to greater
1:33:36than question mark. Next add the rate
1:33:39capital A2 capital Z again bracket slash
1:33:43cap all these things you know small A2
1:33:46small Z again braces
1:33:49almost 90% of the symbols you know right
1:33:51and whatever you're able to witness in
1:33:54front of you you can see symbol number
1:33:56zero symbol number 127 0 to 127 128
1:34:01symbols who gave this America gave it
1:34:05and told this world should Follow this
1:34:07only standard
1:34:09and this is nothing but the code. For
1:34:12example, I will say capital A but for my
1:34:16computer 65 0 and1 version will be
1:34:19there. I will say small Z somewhere over
1:34:23here for me it is Z but for my computer
1:34:26122 if I ask you to convert to binary
1:34:29can you convert it? That is what RAM
1:34:31will store. So information is getting
1:34:33interchanged and this table what you are
1:34:36able to see in hi-fi terms we call it as
1:34:39ASKI table and what is the full form of
1:34:42ASI American standard code for
1:34:45information interchange
1:34:48why is this called as AS as simple
1:34:51America gave it to standardize this
1:34:54world everyone should use this only this
1:34:56is the code for information interchange
1:34:58only between binary and human
1:35:00understandable so if I take All the
1:35:02starting letters it's your ASKI. This is
1:35:05your ASKI table.
1:35:08This ASKI what you're not hearing for
1:35:10the first time in colleges you have
1:35:12heard right. Huh? What did you
1:35:15understand in college? Asky. Ask
1:35:18important asky. CS aski. That's it. That
1:35:20is all we know.
1:35:23So this is nothing but your ask. But the
1:35:26real question is I'm just asking what
1:35:29you know already. Does C programming
1:35:31language follow ASKI?
1:35:33>> Yes, it follows ASK only. So C
1:35:35programming language is English biased.
1:35:39Any software you build using C can only
1:35:43support English. But the good news is
1:35:46Java will not follow ASKI. So then this
1:35:50much buildup you gave no listen to that
1:35:53Java does not follow ASKI because today
1:35:56whatever Android you're using you have
1:35:58multiple language support. WhatsApp is
1:36:00supported in multiple languages. Your
1:36:01Google keyboard can support all the
1:36:03languages. So Java will support multi-
1:36:06languages. Multilingual programming
1:36:09language is your Java. So if ASKI is not
1:36:13followed then what is followed sir? If
1:36:15you ask me let's understand that as
1:36:17well.
1:36:19See before understanding that when I say
1:36:21a just same question in my computer can
1:36:24I directly store a in my RAM?
1:36:26Impossible. So what is going to happen
1:36:28if you ask me? A will get converted into
1:36:31zeros and ones. How? Observe. If I just
1:36:34go back to that ASKI table once again
1:36:36have a look at it. Where is A? If you
1:36:38ask me somewhere over there for you, I
1:36:40bought one binocular lens also a
1:36:42magnifying lens 65. My question is if I
1:36:46ask you to convert 65 to zeros and ones
1:36:48you can do it, right? Same thing
1:36:50internally also will happen. So for you
1:36:53it is a but for my RAM 65 is divided
1:36:57with two 2 32 times again I'll divide it
1:37:01remainder is 1. Next 2 16 are what is
1:37:04the remainder? Zero. 2 8 are what is the
1:37:06remainder? Zero. Again 2 4 are remainder
1:37:09is zero. Last but not least two 2's are
1:37:12zero and two 1's are. And if you notice
1:37:16one thing for you it is a for my RAM it
1:37:20is 1 0 0 0 1. Are you understanding?
1:37:25Everything that you type including your
1:37:28Android mobile phone also the message
1:37:30that you send. Hi, how are you? Missing
1:37:32you and all. Also, every character will
1:37:35be converted into zeros and ones. Are
1:37:38you understanding? So that is what I'm
1:37:40trying to say.
1:37:41Any doubts? Of course, that is your
1:37:43binary. But my question is this is the
1:37:45most important question. How many bits
1:37:47did I get?
1:37:49>> Seven bits. What is the minimum memory I
1:37:52can get from my RAM?
1:37:54>> One bite. Eight bits. Which means in
1:37:57this one bite I will try to fit all the
1:38:00eight bits but one space is empty what
1:38:02will be there? Zero. This comes to the
1:38:05most controversial question in the
1:38:06interview. Is ASKI seven bit or 8 bit?
1:38:11Think and answer
1:38:14smartly.
1:38:16This question I think you might have got
1:38:17somewhere. No, they'll ask. I'm saying
1:38:21no. Tell me is ASKI code a seven bit
1:38:26code or 8 bit code?
1:38:29>> If you are smart how you will answer is
1:38:31ASI is a seven bit code but in the RAM
1:38:34it is stored as 8 bits because the
1:38:36minimum memory my RAM can give is 8
1:38:38bits. Are you understanding? ASI itself
1:38:41is 7 bit only but in the memory it is 8
1:38:44bits. Why? I hope you understood. So
1:38:46this is how you can answer clear but
1:38:49anyways
1:38:51my A whatever you are able to see
1:38:54this is how you write even in C also
1:38:56character CH equal to A correct now the
1:39:00question is look at the memory and tell
1:39:02me how many bytes will it occupy
1:39:06look at that and tell me one bite so in
1:39:09C programming language how many bytes
1:39:12does my character data type occupy if
1:39:14you ask me one bite No doubt about it.
1:39:17So one bite. But what about Java?
1:39:20One bite or some other answer.
1:39:24So in Java same code only you'll write
1:39:27character CH equal to A. In Java it is
1:39:30not one bite. Sir how many bytes sir?
1:39:33Two bytes. Sir why sir? Two bytes. A a
1:39:3765 right? In Java also 65 only. Then why
1:39:40sir? What is the problem? To understand
1:39:42this you attend my tomorrow's class. I
1:39:44hope you understood. So in tomorrow's
1:39:46class, we'll understand why Java
1:39:48supports all the languages and why it is
1:39:50not one bite, it is two bytes. So we'll
1:39:53continue with interview questions on
1:39:55data types in tomorrow's class. Okay? So
1:39:57thank you very much. If you have any
1:39:59questions, please come and meet me. Same
1:40:01place, same time. Tomorrow we'll meet.
1:40:03Thank you.

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