0:00:00.000,0:00:05.928
Hi there, my name is Nick Parlante, and[br]this is the class that explores the basic

0:00:05.928,0:00:11.264
qualities of computers. How they work,[br]what they can and cannot do. And it

0:00:11.264,0:00:17.096
requires no computer background at all.[br]It's just geared for anyone. So before I

0:00:17.096,0:00:21.950
get started, I'd like to, take a moment[br]to, thank Google for supporting my early

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research, into this topic, which[br]ultimately helped make this class. Also a

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quick format note, This class is not just[br]made of videos. For each video section,

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there's sorta this written document which[br]I'm, I'm scrolling through here, that,

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parallels the explanations and has[br]diagrams, and code examples, and stuff in

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it. So, really at any time, you can switch[br]between the video and the document if

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you'd like to reread an explanation or try[br]one of the examples or something. There's

0:00:49.904,0:00:55.757
a big difference between watching me do[br]something and then trying it yourself. So

0:00:55.757,0:00:59.650
my advice would be. A lot of times, at the[br]end of a section, we'll have some

0:00:59.650,0:01:02.952
exercises. And so, at that time, before[br]you try the exercises, you could decide,

0:01:02.952,0:01:06.558
well, are you ready to just jump into the[br]exercises, or would you like to go back to

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the document and try some[br]of the experiments yourself to sort of

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cement the knowledge? So, you should at[br]least know that that's available, for each

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one of these sections. So I will say that[br]the, the fundamental equation of computers

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is computer equals powerful plus stupid.[br]Powerful in the sense that computers can

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do just billions of operations. They work[br]just inconceivable fast. But, the

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operations are stupid in the sense that[br]the operations that the computer can do

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are just very simple, they're totally[br]mechanical. They don't have anything that

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you would describe as human insight about[br]what they're working on. So this weird

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combination of, sort of, great power[br]combined with sort of a mechanical

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stupidity. That pattern will come through[br]very clearly, as we work on these little,

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code examples, to sort of play around in[br]the, in the computer world. Now, I'm being

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a little provocative, sort of making fun[br]of the computer. Oh, they're so stupid,

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and, but on the other hand, we see that[br]computers are, they're very useful. So, in

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a way, that's what this class is[br]about. On the one hand visiting this kind

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of funny computer world that's sort of[br]mechanical, and then connecting it to the

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way, you know things like email, and MP3[br]audio. Things that in the real world that

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are very useful. Trying to sort of connect[br]those two worlds, and show you how the

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computer works, and how it fits into the[br]world. My goal is that, coming out of the

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class, you understand how computers work[br]and how they fit into the world. And

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in a way, you're not intimidated by the[br]computer. You don't think of it as some

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magic, inconceivable box. Also I have a[br]hidden agenda. There are too few computer

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science people in the world. There are[br]many problems that we would like to be

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solved, but there just aren't enough[br]people out there to program them all. So

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my hidden agenda is that by opening your[br]eyes to the computer world and how it

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works for some of you, you may find that[br]you're interested in pursuing computer

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science in the future. So, first[br]approximation I'm gonna look at; How does

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a computer work? So inside the computer is[br]really driven by code. And we're, we'll

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get into a lot more detail on this later.[br]This will just be our first look. So here

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I've made a little picture of a[br]computer. And code inside the computer is

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made of these simple instructions. So one[br]instruction might be to add two numbers,

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you know, compute what one plus one is or[br]check if two is less than ten. So what the

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computer does, for this first look, is it[br]just runs down this list of

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instructions. Each instruction is very[br]simple and the computer is just running

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down the list doing them, albeit it's[br]doing them very quickly. But each

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instruction has this very mechanical kind[br]of fixed feeling. So, I'm gonna say this,

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I think this leads to a natural question.[br]Which is, well; If the, if the computer is

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so mechanical just running through the[br]instructions, how is it that there are so

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many useful features in the world? So,[br]I've got this diagram for that case. So,

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on the right hand side I'm going to[br]imagine some useful features. Like,

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red-eye reduction, or instant messaging. And,[br]I'm gonna say for this discussion, you

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know, your phone, your digital camera,[br]those are all computers. So on the right

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hand side, I've got the useful feature,[br]red-eye reduction. And on the left hand

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side, I've got the computer, which is just[br]going through its, you know, simple

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mechanical instructions. So what[br]connects these two views? And the answer

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is that really, that's what computer[br]programming is. There's a person, a

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computer programmer, who at first they[br]have an idea. Oh, we should have red-eye

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reduction, that would be really useful.[br]And so they use their creativity and their

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imagination to think of what would be[br]something useful to have the computer

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could do. And then what the computer[br]programmer does, is really they structure

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and break down that problem, so that the[br]computer can do it. They really instruct,

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and you know, structure things so[br]the computer can actually, do this

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useful thing. That is what computer[br]programming is. And in fact, any useful

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thing that you've done with your digital[br]camera, or your cell phone, or your

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computer, really behind the scenes, there[br]was a person that was making that happen.

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And I kinda like this combination. In a[br]way, the programmer, the person,

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brings their creativity and insight about[br]the world and thinking of stuff that would

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be useful to have done, and that's[br]their half of the problem. And the computer

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brings what the computer's good at. And I[br]would say the computer is good at being

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ultimately pretty inexpensive. And the[br]computer is able to do these instructions

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very, very quickly and so, we get, you[br]know, ultimately we get this nice

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combination. And in a way that's why there are so many computers in

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the world doing so many useful things. It[br]shows this is this is a good partnership

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between people and computers. In a way[br]this diagram also is a little bit of a

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summary of this class. We're going to[br]visit on the left hand side to see sort of

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see what the computer world looks like.[br]And look at the connection between that

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and actual features that you've used and sort[br]of understand how the computer fits into

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the world and gets stuff done. So, in the[br]second half of this section, I'm gonna

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start doing little, little coding[br]examples. And I should mention, this is

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gonna require a little bit of patience.[br]I'm gonna start doing coding. And our

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first code examples are going be very[br]simple. They are not going to do anything

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flashy. I'll say it's a little bit like[br]LEGO bricks. Each bit of code that we

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learn is one more brick, and eventually we[br]are going to be able to put these things

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together and make stuff that's pretty[br]neat. But these first couple of sections,

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the things, we got to start somewhere, and[br]these first examples are very simple. So I

0:07:04.848,0:07:09.157
ask you to be patient, I promise we will[br]get somewhere neat with this material. Oh,

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and actually here, I put in a little bit[br]of foreshadowing, so actually within a

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couple of hours of lecturing. We'll start[br]doing, visual special effects. And so

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we'll play around with the famous, shown[br]here Monkey Moon Banana problem. So that's

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just a little foreshadowing of where we're[br]gonna get. But for today we're just doing

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simple bits of coding. So for these code[br]exercises, we're gonna be using a computer

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language called JavaScript. JavaScript is[br]a really popular language. It works in

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web browsers, so that's why it's[br]extremely popular. And that's why it's an

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actual fit for this class. Because it,[br]because we're working in the web browser,

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that means our code can work pretty[br]easily. We're gonna use JavaScript plus

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some extensions that I've added just for[br]this class. So this is not gonna look

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exactly like a professional JavaScript.[br]We're gonna work on phrases of code that

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are ultimately quite short. Just enough to[br]sort of get across the points

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that I want to make and sort of explore computers. But without bringing in a lot of

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the baggage that would be required for[br]writing full, professional programs. All

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right, so here's my first code example. So[br]the way code is going to work for us is

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we've got this, little rectangular area.[br]And this text inside of here,

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that's code. And then we'll always have a[br]run button down here. So when I click the

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run button. What's gonna happen is, the[br]computer goes to the top here and it just

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runs through these lines. And so it's[br]gonna, as we say, it's gonna execute

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each line. It's gonna do what it says. So[br]in this case what we're looking at is the

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print function. So there's just the word[br]print. And the way the print function

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works is that it has the word print, and[br]then there's a left parenthesis. And then

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there's a series of things. So here, I[br]just have the number 6. And then eventually,

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the line ends with a right parenthesis and[br]a semicolon. And what the print function

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does is it takes the stuff in between the[br]parentheses, and it prints it out. And so

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actually if you look over here on the[br]right hand side, this is the output of the

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when I hit the run button there. So if I[br]were to change this to say, print(42). And

0:09:09.857,0:09:15.337
run it. Then we see here's the 42. So[br]that's from this first print line and when

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I say print(1,2), that's why we[br]see the, the one and the two over here. So

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the way this works. I did say that our[br]first examples are very, they're not very

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flashy. So certainly that's[br]true here. So I can try you know, adding a

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few more things here. So I could say comma[br]47. So when I run it, okay, now we see we

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get the one and the two in the 47. Also,[br]just to show that these lines are just

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taken one time, I'll copy that one,[br]and then I can paste it in a few times, I

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have multiple lines. So if I run it, now[br]we can say, alright,

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just, you know, we just get a, a[br]repetition of whatever that output was. So

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one thing to, to point out about this, is[br]that the syntax of this code. Is not at

0:10:06.593,0:10:11.297
all free form, It's the opposite, It's[br]very structured. It has to be just so for

0:10:11.297,0:10:16.303
the computer to understand it. And that's[br]actually a reflection of the inner nature

0:10:16.303,0:10:20.465
of the computer. That it has this[br]mechanical fixed quality and so the

0:10:20.465,0:10:25.230
language that it can understand is[br]also gonna be mechanical and fixed. So

0:10:25.230,0:10:30.296
this is a little strange, right at first,[br]that you can't just start free form just

0:10:30.296,0:10:35.302
writing English here and just having, the[br]computer follow it. So think of this as

0:10:35.302,0:10:39.121
your first lesson in the nature of[br]computers. Or you could think of it as

0:10:39.121,0:10:42.507
sort of a when in Rome sort of quality.[br]It's, like, look, I'm asking you to visit

0:10:42.507,0:10:46.067
the world of the computer. And so we're[br]gonna work a little bit in the language of

0:10:46.067,0:10:49.409
computers. It's gonna feel a little[br]strange right at first. But the reality

0:10:49.409,0:10:54.411
is. This is not actually hard. The syntax[br]is, it may be structure, but it's also

0:10:54.411,0:10:59.599
pretty simple. And so, I would encourage[br]you to, don't be put off by the slightly,

0:10:59.789,0:11:04.787
structured mechanical quality of this[br]language. It will enable us to do

0:11:04.787,0:11:10.190
some neat stuff. Alright, that's my first[br]example, let's try a second example here.

0:11:10.400,0:11:16.428
So my first example I just did numbers. So[br]in computer code there's also a thing

0:11:16.428,0:11:21.565
called a string. And here's a first[br]example of a string here. Hi in quotes so

0:11:21.565,0:11:26.537
a string is just a sequence of letters and[br]in the code it's written between the

0:11:26.537,0:11:31.701
double quotes. So that's why I have the[br]"hi". So print can take in numbers and print

0:11:31.701,0:11:36.545
them, turns out it can also print strings.[br]It just interprets the string as just a

0:11:36.545,0:11:41.390
sequence of letters and whatever the[br]string is it just prints them out over

0:11:41.390,0:11:46.445
here. So, I could change this, you know,[br]it says "hi". I could change it to say, "good

0:11:46.445,0:11:51.284
day". So the string can have a space on it.[br]So if I ran that then we'll just, we'll

0:11:51.284,0:11:57.723
just get the good day over here. So in a[br]computer program, strings and numbers are

0:11:57.723,0:12:02.221
both very, very common. So a string in a[br]computer program might be used to hold

0:12:02.221,0:12:06.834
like a URL that you just typed or, maybe[br]in a word processor each paragraph that

0:12:06.834,0:12:11.216
you're working on might be stored as a[br]string. So the string is basically this,

0:12:11.216,0:12:15.598
sequence of letters. It's a very common[br]sort of data in the computer. Another

0:12:15.598,0:12:20.211
thing that's shown in this code example is[br]this first line here. That's called a

0:12:20.211,0:12:24.940
comment, and in JavaScript comments begin[br]with two slashes, and the way the comment

0:12:24.940,0:12:29.632
works is, beginning with the two slashes,[br]everything to the right on that line the

0:12:29.632,0:12:34.880
computer ignores. And so I could use that[br]to write some remark about, you know, oh,

0:12:34.880,0:12:39.749
I have two strings here. Some little[br]remark or note to myself or something

0:12:39.749,0:12:44.807
about the code. And so when I run this,[br]the computer knows to sort of ignore this

0:12:44.807,0:12:49.865
part. Oh, that's just commentary. So, in[br]some of my examples later on, you'll see

0:12:49.865,0:12:55.176
comments sprinkled around where I'm, I'm[br]making some remark about, what's going on.

0:12:55.365,0:13:01.738
So one example I could do here that's a[br]little tricky. Is, I'm gonna put the word

0:13:01.738,0:13:09.411
print inside of this string and we'll see[br]what that prints. So here and now, the

0:13:09.411,0:13:14.807
second line, I get hello to print. So[br]what's happened is, the word print inside

0:13:14.807,0:13:20.622
of a string is not treated as code to run[br]the way the word print outside, that is a

0:13:20.622,0:13:26.158
function that the code is called. So when[br]it's inside of the double quotes like

0:13:26.158,0:13:31.889
that, it's just data. So that is a, a[br]distinction inside of the code. Well,

0:13:31.889,0:13:37.719
alrighty. So, I'm gonna, at the end of[br]this section, we'll have some exercises

0:13:37.719,0:13:43.908
where you can write some code as I've done[br]here. So as I mentioned before,

0:13:43.908,0:13:50.102
the code works within the system of being[br]a very structured limited syntax. And it's

0:13:50.102,0:13:54.603
actually a very common error, even a, you[br]know, a professional programmer who

0:13:54.603,0:13:59.455
writes code all day long. When they're[br]typing in some code, there will tend to be

0:13:59.455,0:14:04.249
little syntax errors, sprinkled through[br]the code. Oh, maybe a right parenthesis

0:14:04.249,0:14:09.218
is missing or there's a typo in one of the[br]words. And, those syntax errors are very

0:14:09.218,0:14:13.719
easy to fix. And so it means that when[br]you first hit that run button,

0:14:13.719,0:14:18.513
it is very common that there'll be some[br]little typo that has to be fixed. And I

0:14:18.513,0:14:22.769
want you to understand that. Those little[br]errors do not reflect some deep

0:14:22.769,0:14:27.484
misunderstanding on your part or some flaw,[br]those are just superficial little errors

0:14:27.484,0:14:32.083
that happen in coding all the time. And[br]professional programmers make those all

0:14:32.083,0:14:36.624
the time, and we just think nothing[br]of fixing those. We, we don't even think

0:14:38.894,0:14:41.164
about it anymore. And so, I think that, when[br]people are first introduced to coding,

0:14:41.164,0:14:45.647
this is something that derails them a[br]little bit, that there are these little

0:14:45.647,0:14:50.129
syntax errors and it kinda, it puts them[br]off their game and they think they're doing something terribly wrong when in fact, everyone

0:14:50.129,0:14:54.707
makes those errors. It's absolutely no big[br]deal. So. To help, diffuse that problem a

0:14:54.707,0:14:58.131
little bit, I just wanna go through a[br]bunch of examples where I've... So, I've

0:14:58.131,0:15:01.691
set up some examples here, where I just[br]have typical little syntax errors. And I

0:15:01.691,0:15:05.206
wanna show you what the error looks like[br]when you hit the run button. Right? So

0:15:05.206,0:15:08.946
what's gonna happen is, when I hit the run[br]button, it's not gonna work. I'm gonna get

0:15:08.946,0:15:12.461
some kinda little error. And so I wanna[br]show you the process of going from the

0:15:12.461,0:15:15.795
error and fixing the little syntax[br]problem, just so you're a little bit accustomed. Like,

0:15:15.795,0:15:19.220
oh yeah, when you first hit the run[br]button, that's a very common thing that's

0:15:19.220,0:15:22.554
gonna happen. So, let's just go through[br]these. Alright, so I, I hit the run

0:15:22.554,0:15:26.380
button. And, you know, instead of running[br]and producing output, I got a little bit

0:15:26.380,0:15:30.031
of an error over here, a little error[br]message. Sometimes the error messages are

0:15:30.031,0:15:33.729
pretty good, describing what's going on.[br]So, let's read this first one, It says,

0:15:33.729,0:15:38.719
Error: prlnt is not defined. So,[br]what's going on here, is print is a

0:15:38.719,0:15:44.141
function, But this second one here, line[br]two, and the, actually in this case it,

0:15:44.141,0:15:49.920
well, this won't always work, but a lot of[br]times it'll highlight the line that has

0:15:49.920,0:15:56.342
the problem. The problem is that it's a[br]typo. It doesn't say P R I N T, it says P R L N T.

0:15:56.342,0:16:01.054
So if I change that to an i. Ha![br]Now it works. So, this little program just

0:16:01.054,0:16:05.101
prints A, one and a B, a two and a C and a[br]three, so it's just a little pointless

0:16:05.101,0:16:09.302
example I made up. Now of course, I did L,[br]because I was trying to think of a what's

0:16:09.302,0:16:13.246
a letter that looks like an I. You would[br]have to come look carefully, so I was

0:16:13.246,0:16:17.183
being a mean professor there. Alright,[br]let's try another one of these. So I'll

0:16:17.183,0:16:21.666
hit the run button on this one. It says[br]error, unterminated string literal, and it

0:16:21.666,0:16:26.319
highlights the second line. So I'm just[br]gonna look at the second line from left to

0:16:26.319,0:16:31.085
right. You see the one, and there's the B,[br]So you see, the problem here is that this

0:16:31.085,0:16:35.624
is a string. Our intention was the string[br]B, but the closing quote is missing. You

0:16:35.624,0:16:40.709
need both quotes. I'll try the third one here. Let's

0:16:40.709,0:16:45.136
see, error, missing right parenthesis. So[br]again, it's highlighting the line. So I'm

0:16:45.136,0:16:49.446
gonna, actually, so in this case, the[br]error message is actually

0:16:49.446,0:16:54.275
pretty good. It's just saying, hey, look.[br]As with the quotes, the left parenthesis

0:16:54.275,0:16:58.478
and the right parenthesis, they need to[br]match. Like there must be a right

0:16:58.478,0:17:02.951
parenthesis there, exactly there for the[br]print command. So now that one works.

0:17:02.951,0:17:12.220
Alright, here's the last one. Something[br]wrong, it says error, missing right parenthesis, but I looked and the right parenthesis is there. but it happen to this case

0:17:12.220,0:17:16.165
the error message is just wrong.[br]Sometimes, when there's a syntax error,

0:17:16.165,0:17:20.787
the computer, it just becomes confused and[br]it cannot diagnose for you in the error

0:17:20.787,0:17:25.240
message, it can basically just say, well,[br]something's wrong in line two here. So I

0:17:25.240,0:17:29.974
recommend just looking carefully from left[br]to right and look here, it looks

0:17:29.974,0:17:34.401
pretty reasonable. It happens, in this[br]case what's missing, is the comma. And I

0:17:34.401,0:17:38.624
think that's an example of maybe the[br]difference between computers and humans. A

0:17:38.624,0:17:42.795
human could look at that and see your[br]intent. Like, oh, I see the intention here

0:17:42.795,0:17:46.965
was to print a one and then a B. But the[br]computer with this mechanical quality,

0:17:46.965,0:17:51.771
it's like. Things have to be just as[br]they're supposed to and so the comma is

0:17:51.771,0:17:57.121
not optional there must be a comma there[br]and so we're stuck until we fix it. All

0:17:57.121,0:18:02.999
right. Now that one works. Okay. So that's[br]our first section of just basic print

0:18:02.999,0:18:09.120
with, numbers and strings. I've got one[br]example problem here that I'll try. So this is

0:18:09.120,0:18:13.688
what the exercises will look like a lot of[br]times. Although the later exercises will

0:18:13.688,0:18:18.036
be more fun, I do promise that. So it[br]says, change the code below so that when

0:18:18.036,0:18:22.548
run it produces exactly this output. So it[br]says one, two, buckle, so this is based on

0:18:22.548,0:18:26.438
the, one, two, buckle my shoe. So this[br]code, there, there's a code here that does

0:18:26.438,0:18:29.911
something, but it's just not, not the[br]right thing so we're supposed to change

0:18:29.911,0:18:33.384
it. Let's see. For one, so what I'm gonna[br]do is I'm gonna add a two, and then I

0:18:33.384,0:18:36.993
gotta remember to put in the comma, and[br]then I'll change this string to be a

0:18:36.993,0:18:40.694
buckle. Now I can just run it, just see[br]what that does. I'd encourage you to, you

0:18:40.694,0:18:44.349
know, if you have some idea of the code,[br]or you just wanna try something, you know,

0:18:44.349,0:18:48.142
you're never gonna break anything by just[br]typing something in here and hitting the

0:18:48.142,0:18:51.889
wrong button. So, it's good to have a feeling of experimentation. So,

0:18:51.889,0:18:58.721
there's the first line. And I'll check the[br]second line. So three comma, four comma,

0:18:58.721,0:19:07.456
knock. Alright, oh, right, now that works.[br]So often times when I do a little examples

0:19:07.456,0:19:12.952
in a document like this It might be that[br]in the video, I'll do a bunch of

0:19:12.952,0:19:16.592
examples and then you may wanna go try,[br]you know, be, you'll be curious about the

0:19:16.592,0:19:20.509
second one. And so you wanna go visit that[br]one and try some variant and hit the wrong

0:19:20.509,0:19:24.150
button yourself, that is absolutely[br]something you're, you're free to do. Often

0:19:24.150,0:19:27.467
times, in the document, I'll have the[br]little show solution button. So, that

0:19:27.467,0:19:31.061
means, that you can go visit it and it's[br]blank, so you could do your experiment.

0:19:31.200,0:19:34.748
But if then if you're curious what the[br]code was that I used, then that's also

0:19:34.748,0:19:38.204
available in the document so you can[br]compare it to your solution. Or if you

0:19:38.204,0:19:41.752
wanna copy out of it, or whatever, that's[br]fine. Okay. So, that finishes our first

0:19:41.752,0:19:44.940
section, so check out those coding[br]exercises.