Alright, welcome to the last CS1 Lecture
Session. There's not going to be exercises

for this section. I'm just going to try
in, I don't know, summarize what it all

means and talk about some next steps. So,
for CS101, I took the strategy of just

jumping right in with code really and we
got into the detail of codes and played

with the code and my plan was that as you
played with code and have bugs and

experimented that you would gradually just
come to see what some of the features are

of the computer. So, I hope that works.
Today I'm going to step back and talk a

little bit about what it means and
[inaudible] and things so first thing I

want to talk about is this word algorithm.
I may have used here and there. Algorithm

actually it's named after a Baghdad
astronomer Al-Khwarizmi. Some of his work

ends up in the word algebra so he's rather
influential. So the given algorithm Refers

to the steps to take to get something
done. So, not just saying well I want this

script to be you know blue. That's just
saying what the goal is. The algorithm is

really figuring out something to describe
one step sort of. Now it's not the same as

syntax. Syntax is really a computer
language feature so algorithms I would say

capture really human, human creativity of
how I might going to solve something And

really, for CS101, very often for the
exercises are in lecture examples. I've

been describing an algorithm. Oh, take the
picks and do this and do that, whatever

describing the, describe is going to be
And then I've left it to you to, to then

phrase into code and that, that's just a
totally classic computer system way to

work. You have human, you have the idea,
unless you get phrased in the code. I'll

have other bunch of examples sort of. Hit
that pattern. So this is an example, I

won't go to the details exactly but here's
the code from the Monkey Moon example and

so we had the strategy of like computing
average and then trying and find the blue

background behind the monkey and then copy
the red, green, and blue pixels that is

over. So such thin g is that, that's the
idea which was pretty complicated and you

know effective and then here it is
expressed into code And party, I mean,

it's a little bit of amazing that we did
and my code is fairly complicated, right?

So, at least a couple of weeks ago, you
didn't, you didn't understand this so it

also shows the gap where we had this plan,
what we're going to do but then look at

the individual steps in the code. Pixel
dot got red. You know, average times

you're pointing on too. The building
blocks that the computer has are really

pretty simple and I just get that. There's
no insight, it's just mechanical and then

in a way, they get what a computer
programmer does. I've taken an idea that's

interesting and valuable and sort of
phrase it down to the computer, break it

down into the little mechanical steps that
the computer can do to sort of build up

the program that we like one And that's.
That's a key example. That is what, that's

what the modern world looks like in terms
of the computers, computers doing some

usual stuff. So, as long as I was talking
about code, you know, having an algorithm

for phrasing them to code, I also thought
I could revisit the word bug. I'm sure

this is a word you've all heard at one
time or another. Here's a little example

of a bug where I, I have to [inaudible]
over the image. And then here I've

mentioned I'm trying to change the image
to gray. So, I could help the line of

average equal pixels to get red plus get
green plus get blue/3. The problem here

This code does something. It just doesn't
compute the averages I intended. The

problem here is that the slash three only
applies to get blue. We would need to put

[inaudible] in here to make it work right.
So the results is that was [inaudible] and

so the numbers going to come up like 450,
just way too big and so setting it in to

the image makes the image come out almost
near white. This is just an example of a

bug where there was intent, well here's
the other thing that I might want to do.

But the code I typed in Said something
else. It, it said something but it had

steps the computer could follow but it
wasn't the ones I intended. And that's.

That's very often what bugs looks like and
I'm sure you've have run in the bugs all

the time. So there's a little insight of
how, where the gap was between the intent

of the programmer and running out the
steps for the, the computer actually do so

this sort connection I'm talking about is
at the very start of the class I made this

kind of a provocative claim well you know
computer is to powerful plus two. Computer

is so stupid and limited and I stand out
of that I think because you have seen

[inaudible] limitations and yet. That was
very useful we have e-mail and the

Internet and computer games. All of these
are phenomenally valuable awesome useful

stuff so how that works? And I guess
ultimately the answer is humans, That a

human programmer had a creative, an idea
of like here's what I'm going to do and

this is going to be great and that's
really where, that's what computer

programming are, that's what computer
programmers are and that's where computer

science is about and then it gets broken
under these steps with the computer can

actually do it. So I just have some, some
examples here. Grab some of theses from

Stanford so these are examples where you
have the computer installing these

mechanical stuff between something
[inaudible] it's kind of professional. So

Daphne [inaudible] at Stanford has this
awesome research on grading cancer cells.

So basically, you have a [inaudible] dish
with some sample cells in it. And you show

a computer an image of it and then the
computer is going to eventually, she

trains the computer to do great, so
something that normal humans do that's

actually pretty difficult and humans have
a tough time doing a good job out of it.

And so, but when I get that, this looks
like a little bit like our image code.

It's not that you just say that the
computer, hey, I want you to grade this.

Really, you know, the computer just has.
Values, you know, bunch of numbers and can

do less than and gr eater than, you know,
loops are those building blocks and so the

[inaudible] ingenuity to phrase up an
algorithm for the computer using it's

simple [inaudible] to do something
profoundly useful like [inaudible]. I'll,

I'm just putting links here. If you want
to visit the document then you could try

this up. Another example of this just sort
of amazing is there's a treatment for

certain forms of deafness called the
cochlear implant and this is a little bit

of controversy about the deaf community
about if this is a good idea or not but it

is amazing. Other works is there is a
microphone that takes in sounds and the

sound waive is kind of like we saw in the
analog and digital lectures are processed

by a computer and eventually ultimately
ending up going into wires that go

directly in to the, the sense organ in the
head and so. It's, it's possible to give,

not exactly hearing but sort of hearing
for someone who is potentially completely

deaf before. So there's, I gotta say, a
fairly amazing video Youtube video clip

here of the baby hearing their mother's
voice for the first time. And so it's,

it's what's saying, future is about that.
I gotta say, if I was an engineer who had

anything to do with this project, I would
very proud. Like that is a, it's such a

vivid example of the technology really
changing someone's life Last example.

Also, a part from Stanford is this idea of
self-driving car. So this involves, the

car has all sorts of cameras and range
finders on it and it's sort of, I'll put

it in quote. It's Kind of seeing
surrounding and trying to understand what

the obstacles and pedestrians, whatever
are and then making decision in real time

like it has to decide right now what to
do. That's profoundly a hard problem. But

so Sebastian's run at Stanford and now we
can do this in Google he has made a lot of

partners with this and I gotta say, I'm
sort of a national optimist but I think

this is all going to happen. I think it's
going to happen because although the

technological challenges are enormous,
ultimately it will sa ve time And as

society becomes more wealthy, time is just
something everyone values. I think that's

going to provide a lot of pressure to
make, make this work so I'll be, I'll be

interested to deliver long enough to see
that working. All right So I want to talk

a little bit about you know post C101,
things you might want to think about. So

Most people are not going to be computer
programmers, That's fun we need more but

life certainly is not for everyone. So I
think there is kind of a skill to just

working with computers. Computers
obviously have the sort of mechanical,

slightly fragile and I think that just
have to be just so way that are. And my

hope is that, with CS101, you've seen how
that is at times and in different ways

that you, it's [inaudible] you a little
bit of confidence and a little bit of

patience. I think sometimes, people
[inaudible] something in the computer and

I click the button and it doesn't do what
it's supposed to. And there's, there's

sort of stuck of well what I do know. And
I think they can get past that stuff

whereas now, I think you've seen the, the
kind of the mechanical quality of the

computer. My hope is to have a little
patience. So, okay, well, we're not doing

what it's supposed to, let me read the
docs again, there's probably some little.

Dumb thing right I'm missing semi colon or
whatever. Some little detail that computer

is going to get trip by and so I think
there is a skill to no getting derailed

when a computer messes up like that and
I'd like to thank that CS1 on help. I'll

give you what skill a little bit. It's
certainly a very handy life skill since

computers are everywhere. So finally let
me list of. Classes where thing, things

you might want to study after CS101, I
have bad news about this. There is not a

class which I think is really a good fit
to just be right after CS101 there is just

one that I know of so I'm not going to
recommend the specific one but there's a

lot of research and activity in that area.
Someday day maybe I'll create one but I'm

done yeah. So I'm just going to mention
things that you could look at sort of

Poseus point of view. So one thing I'll
mention is spread sheet. Spreadsheets are

very commonly used to organize data or do
computations or whatever; you probably,

probably heard them. So the next time you
see a problem where someone says oh hey,

we could do a spreadsheet for this I'd
say, you might want you know, you could

consider. You might want to take a shot of
that. The sort of "programming in

spreadsheets" is not that different from
what we've done. Microsoft Excel is a

super popular spreadsheet but it's not
free. The Google Docs spreadsheet is free

and actually it uses JavaScript which is
the language we've been using so. Is just

so I guess have a question of, of
confidence of being open like, be open to

reading the docs and reading some examples
I'm trying to use them specially I think

would not be much a lot of them from what
we've done and they're very common. Very

commonly used for, for problems, for
problems like that. So another next step

is to take a sort of your general college
introduction to [inaudible] course. A lot

of colleges just have this and I think
some high schools to. So Cs101 is not a

general programming course. I had the
analogy somewhere that it's as if there is

this island and it has. Hundred miles of
trails on it which represent all the

different types of program you might want
to do and a way when a time with CS101 is

I've, I have very carefully chosen fifteen
miles of trail. So, I've showed you, you

have seen real programming issues. You
definitely have the sense of what bugs

are, what those are and those are
absolutely vital core programming and of

course, you, you have done them
[inaudible]. However There is the 85 other

miles all sorts of stuff. I didn't talk
about it. I sort of constructed my

examples and the way the lectures work to
just carefully use the things I talked

about and not trying to get distracted by
all of the stuff I didn't talked about. So

you just know. That's kind of CS101 leave
you versus the regular program and c

ourse. In a way you've been a nice head
start. You've seen all these computer

stuff. You have seen loops or whatever
setting. You have got a bit of a tail end.

Going to it, general programming course
You would expect it to move faster than

CS101. I was pretty, I tried to keep CS101
at a pretty measured hay anybody can do

this. I don't want to be able to,
stressful experience. So you, you would

expect a bump up in the speed but
certainly something I'm sure many of you

would enjoy doing. So something about I'm
just going to mention a couple other, a

sort of specific type of programming that
people talked about. So HTML five or first

to web page programming that's done with
HTML, Javascript and CSS. We've done

JavaScript in CS101 but I gotta tell you,
the JavaScript for web pages is going to

look more complicated, have more going
out. We, we do this very stripped down

very focused type of JavaScript. So, for
lot of these kind of topics that I

mentioned here. A, the [inaudible] college
students when we think about it is that

you take the General Programming course to
just sort of get a general loop statement

sort of experience to have a sort of
generic ability and then you make the

specialized and learn about web pages or
something. It happens when programming is

not that hard and so it's possible to just
to skip in the web portal in like just

have a HTML five or whatever. Of course
and just sort of just learn the Javascript

in the contents to that. So. Other than
that, I've gotten questions about sort of

various areas and I, I, I find it hard to
identify anyone in particular I say, yeah,

there's phone programming, game
programming, finance programming and

science programming, that, that, that.
What I can tell you is. It's a huge field.

There's at you know, science, air
dynamics, finance, I mean, any, anything

you could mention. There's, there's
computers going on and generally, it's

regard to there's tends to be a shortage
of people and so if you are interested

about computer, you know, if you learn
about computers and y ou want to work

with, anyways, there's a good chance that
you could. There is demand for people who

know that stuff. So I guess I have to sort
of summarize the, the course here so I

might claim at the very start of the class
was the CS1, CS101 teaches the essential

qualities of computers by playing with
code. You've certainly played with a lot

of code at this point so I hope that sort
of holds up my fear Is that people go

through life. They use computers all the
time but they see the computers are sort

of opaque and not comprehensive but
something they could never understand and

I hope I hope I have put that down. That
you can sort of see through the other side

and appreciate oh The computer is working
this way and then I can know this sort of

thing, Whatever so just sort of pretty in
context of how computers work in your

life. So as I said before I also hope
that, with that knowledge CS101 gives

everyone a little bit of confidence and
maybe a little bit of patients to work

with their computers and kind of get them,
get computers to work for them. They are,

as what I've said they are stupid
mechanical but. They're also incredible

useful. Alright, take care.