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Instructor: What is a programming language?

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If someone asked you this question, can you answer it?

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Programming is simply a way for us

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to give instructions to computers.

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We give it an instruction manual, and the computer follows.

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Without code, computer programs wouldn't do anything.

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You wouldn't be able to move the mouse around

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on your screen.

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You wouldn't be able to Google things.

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You wouldn't be able to play Pokemon on your phone, right?

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I can't just tell my computer what to do.

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You see, computers don't understand English,

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or any other human language for that matter.

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So what language do computers speak?

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Well, they speak in ones and zeros.

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All electronics speak that language

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of on or off, zero or one.

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But writing ones and zeros would be gibberish for us.

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It's hard for us to communicate like that, right?

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So humans have developed programming languages

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that are in between human language and machine language,

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that is, zeros and one.

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Some programming languages are lower level than others,

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that is, they're closer to machine language.

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And other programming languages

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are higher level than others,

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that is, they're closer to English or a human language.

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And there are lots of programming languages.

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You have languages like Assembly

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that is really, really close to machine code.

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You have languages like Python and JavaScript

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that are really, really close to English.

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Okay, that's great.

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We have these pieces, but what are we missing here?

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I mean, if I wanna find flights to Hawaii,

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how do we go from here

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to, well, having, let's say, a website

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show us a display of all our flights,

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telling the computer to show those flight information

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on our screen.

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What are we missing here?

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Well, we have these programming languages

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that we usually write on a file

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such as Python, JavaScript, maybe even Java.

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And then, we somehow need to get these files that we write

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into ones and zero so that our machines can understand.

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Well, we need a translator, right?

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We take our code that we write, what we call a source code

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written in a programming languages,

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and we give that to a translator

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that can understand that language

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but also understands machine language.

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And this translator just translates these files for us.

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So what is this translator?

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It's not really a person, right?

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I'm not giving my code to somebody,

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and somebody's going to just start shouting at the computer.

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That'd be quite silly.

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What is this translator?

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Ready to have your mind blown?

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Well, it's another program written by a human.

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It can either be an interpreter or a compiler.

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Now, Python usually uses an interpreter, usually.

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And an interpreter, just like a translator,

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goes line by line through our code

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and executes our code on our machine.

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Compilers are a little bit different.

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They take your code all at once,

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reads the entire file all at once,

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and then translates that to machine code.

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So again, interpreter goes line by line,

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and each line executes an instruction.

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A compilers takes the entire file

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and turns it into machine code.

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Now, the differences between these two

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are a little complicated and beyond the scope of the course.

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And don't worry, we're gonna come back to this topic.

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But I want you to just have this general picture,

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that when we write code,

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whether it's Python, JavaScript, Java, C or C++,

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what we're doing is we're typing it

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in a language that is human-readable,

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we're giving it to one of these translators,

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like an interpreter or a compiler, and these spit out code

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that are able to run on our machines.

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So to review, interpreters translate line by line

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and execute the line before going to the next line.

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Compilers translate all lines of a program

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to a file usually called a binary,

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and execute the whole file at once.

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Now, in the next video,

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we're going to talk about this process

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a little bit more in detail,

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especially on how it works with Python.

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But why did I start with this?

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I mean, this is a complex topic.

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Most developers, especially if they're starting out,

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don't even know of this process.

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They just know that they write code and then it runs.

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So why did I teach this here?

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Because in order for us to be able to write Python code,

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well, I can't just write it anywhere, right?

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If you ran right now to your computer

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and let's say you opened up a text file like this one

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and you started typing Python code,

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but for now, we don't know Python,

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so let's just say I wanna go search for Pokemon.

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Well, this might be code, we don't know if it is,

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but I can't just use this, right?

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I mean, this isn't really Python code,

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but how would my computer know what I'm talking about?

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In order for us to start writing Python,

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we need to download this translation service.

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And in the next video, I'm gonna show you how to do that.

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I'll see you in that one.

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Bye-bye.