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>> [MUSIC PLAYING]

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>> SPEAKER 1: All right, everyone.

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Welcome to your last section with me.

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It's been quite the semester.

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I can't believe this is, like,
week 12 or 11, something like that.

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But because it's our last
section, we have lots of candy.

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And I'm going to try and
prep you as well as I

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can for your quiz on Wednesday.

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So probably not the best way to,
like, end section with quiz review.

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But we'll try and make it fun.

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And there's always candy.

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So hopefully, that'll make it better.

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>> Your quiz is going to be pretty
much the same thing as Quiz Zero.

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It's going to be the
same format, same length.

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You'll be in rooms scattered
across campus, because there

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are close to 900 of you, and we can't
all hold you in rooms like this.

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So be sure to look at all of
the Quiz One documentation

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online at cs50.harvard.edu
tonight or tomorrow night.

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Make sure you know where you're
going, what you need to bring.

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Really, you just need to bring yourself
and a pencil, and you should be fine.

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The questions will be
very much the same.

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There will probably be a couple
multiple choice, a couple short answer,

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some coding, maybe some true/false,
matching sorts of things.

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So you shouldn't be too
surprised by the format.

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>> What can be surprising is the
length, which, in previous years,

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has been much longer.

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In my year, I don't have a single friend
that I remember finishing the exam.

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There were like multiple
pages left blank.

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So the length can be
kind of disorienting

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just because in some years, it has
been much longer than Quiz One.

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I have no idea what it's
going to be like this year,

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but it's something to be aware of.

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>> Additionally, the
difficulty-- people tend

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to find Quiz One much more
difficult than Quiz Zero.

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Again, you know, if
you're kind of walking

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out feeling a little uneasy because
you didn't do as well as you thought

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you would or you feel like you didn't
do as well as you did on Quiz One,

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remember that there are probably a
lot of other people feeling that way.

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I was definitely one of those people.

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Quiz one, like, threw me for a loop.

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And my friends have this great
picture of them at JP Licks

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kind of with these huge
sundaes, being like, Quiz One,

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and looking like they're in tears.

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>> So it's a general feeling.

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It's a tough test, it's a tough quiz.

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Obviously, if you come out and you
feel like you rocked it, great for you.

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But know that you're probably not--
you are almost most definitely not

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alone if you walk out feeling like,
eh, probably could have gotten better.

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It's tough.

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Mm-hm.

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>> AUDIENCE: How much is it worth
in relation to [INAUDIBLE]?

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>> SPEAKER 1: It's worth the same.

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Yeah.

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But again, it's also going to be
affected by how the rest of the class

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does, how your section does,
how you've improved over time.

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Grading is a little bit of a black box.

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So what the actual number
or percentage you get

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is not necessarily like directly
correlated with the grade

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you're going to get.

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There's a lot of
factors that go into it.

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>> So with that, we're going to
go through some quiz review.

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I'm just going to run this
like last time for you guys.

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I have all the answers
to Quiz One of last year.

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So if you guys want to pull
that up on your own computers,

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if you've taken this exam
before and you have questions,

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I was thinking we could
just go through some

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of the more difficult ones on that.

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So we can talk about it, maybe
get a little more insight

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into the intuition behind some of
these questions, how to approach them.

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>> As well, like last time,
I have a 100-slide deck

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that has basically all
of the slides that I

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have prepared for previous
sections since your last quiz-- I

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have in this deck.

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So we can go through
pretty much anything

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that we've talked about
beforehand that maybe you

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want a little more clarification on.

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We could do that first.

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>> But otherwise, I'm super
happy just to kind of work

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through these problems with you.

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And I'm really here to
focus on what you guys think

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would be most important to focus on.

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Like, obviously, all of
this stuff is important.

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Especially as we go through Quiz One,
I'll definitely point out things like,

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oh, this might be something
you really want to know

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or you want to have on your cheat sheet.

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I'll be telling you things
as we kind of go through.

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>> So on that note, are there any things
that you guys would like to go over?

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Also, if I don't have it in my deck,
we can pull up something on the web,

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or we can try and make
up an example on the fly.

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But any concepts that you
guys are a little fuzzy on.

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[? Brian, ?] did you have--

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>> AUDIENCE: Oh, is it cumulative?

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Like, is the stuff on Quiz
Zero going to be on here?

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>> SPEAKER 1: It's cumulative,
but it's much more

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of an emphasis on things
since your last quiz.

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So obviously, you guys have
learned about variables, and loops,

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and conditionals.

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And it's not like those just
go away, because they're

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obviously inherent to everything
else that we've learned now.

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>> There might be a question
on the sorts, or there

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might be a question
on different searches.

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Or there might be a couple
questions on maybe something you

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having to do with compiling
or different errors.

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But if you've looked at
Quiz One from last year,

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you'll notice that it is
very much focused on things

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that have happened since your last quiz.

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>> Why is that door always locked?

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It really bothers me.

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Because I always try to go through it.

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>> So that's pretty much
how the quiz will be.

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So are there any concepts that
you guys would like to go over?

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Or we can jump right into
just looking at Quiz One

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from last year and kind of going
through practice questions there.

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We can also switch back and forth.

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This is not a one-time sort of thing.

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Any questions?

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Yes.

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>> AUDIENCE: Could I ask a
question about another--

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>> SPEAKER 1: Another one?

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>> AUDIENCE: This is from another year.

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>> SPEAKER 1: Yeah.

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We can also do another year.

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>> AUDIENCE: OK.

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So on 2011.

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>> SPEAKER 1: 2011.

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Ooh, that was the year before me.

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Let me pull this up.

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>> AUDIENCE: I think.

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>> SPEAKER 1: This aspect
ratio is throwing me off.

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>> AUDIENCE: 11 and 12.

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>> SPEAKER 1: 11 and 12.

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OK.

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Well, here, why don't we do this?

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You guys-- everyone just take a couple
of minutes to look through quizzes.

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And we'll compile a list.

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And then we'll go through them.

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All right?

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While I get a bunch
of this stuff set up.

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OK.

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I'm just going to write
things down on paper.

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>> 2011, 11 and 12?

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I'm just going to change this display.

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OK.

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That's better.

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This over.

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All right.

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>> Anyone else have any that
they'd like to start with?

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Also, forgot to say, if you want more
of a bunch of people talking at you

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and just giving you a crack
course in the last six weeks,

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we are running a review
session from 7:00

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to 8:30 tonight in Northwest
B103, which also happened

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last time, where it's going to
be me, Hannah, Daven, with Gabe

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and Rob kind of helping from the
sidelines of just kind of throwing all

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the information that you might
want to have on your cheat sheet,

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slash, know in general there.

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AUDIENCE: That's also online, right?

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SPEAKER 1: It's also online.

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So you can also stay out of this
icky weather, go to your dorm,

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and live-stream it if you'd like.

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I'm sure a lot of
people-- I know I would

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be doing that if I were in your shoes.

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OK.

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So why don't we start with--
while you guys-- hopefully,

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you're looking through.

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If not, I might just start working
through different things on Quiz One

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from last year unless you
have specific questions.

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>> We'll start with this
question here about stacks.

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So does everyone remember
kind of what a stack is?

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How we tend to-- can anyone just give
me a general description of a stack?

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A type of data structure.

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OK.

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So it's one of the
data structures that we

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expect you to be familiar with-- like
stacks, arrays, queues, so forth.

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Yes.

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>> AUDIENCE: Like First
In, Last Out, something.

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>> SPEAKER 1: It's First In, Last Out.

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Exactly.

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So a stack is exactly
what we tend to think

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about when we think
of a stack of things.

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So a stack of plates.

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The first plate you put down
is going to be at the bottom,

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and it's going to be the last
one that you remove at the end.

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Because they stack up.

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>> And you take the one out of the bottom,
typically, things crash and break.

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So stacks you can think of
just like a stack of plates.

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Or the example we always like to use
is in the D halls, you have the trays,

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they're all stacked up,
and you take from the top.

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So the last one in is the first one out.

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OK.

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>> So in the case here, we
see we have-- I wonder

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if I can actually zoom in a little bit.

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So we have this struct here.

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Right?

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So you have some struct that has
some int numbers of capacity.

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So what do we think that represents?

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This is an array with size CAPACITY.

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>> So this really represents
our stack in general.

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Our stack is really just an
array with some set number

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that is its max, that is, its CAPACITY.

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And then we have some int size, which
will track the size of our stack

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throughout the course
of when we're using it.

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OK?

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>> In this case right here, we say that our
stack size has been initialized to 0.

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So we have an empty stack right now.

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And then we want to complete
the implementation of pop

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such that it returns the int at the top.

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And then if it's empty,
it returns negative 1.

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OK?

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So I want you guys just to think
about what we might do there.

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What might be one of the first
things we'd want to check?

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There's a great thing here.

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Whenever it says-- if there's ever some
If statement, like "If stack is empty,"

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or "If this returns null," or
"If this is whatever"-- sorry.

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>> AUDIENCE: Write an If statement.

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>> SPEAKER 1: Right.

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You could write an If statement.

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And that's probably one of the
first things you want to check.

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OK.

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Whenever they give you
kind of like a corner case

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like this, that's typically
one of the first things

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you're going to check in your code.

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>> Also, something to
recognize for the quiz

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is if you have an inefficient way
to do something, write it down.

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Because we're not grading
you on design, we're

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grading you on correctness for quizzes.

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So even if you know that it's a super
bad way to do something but it works,

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write it down, OK?

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>> Literally, I've seen kids last year--
if you look at last year's one,

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they're like, do the Mario pyramid.

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And they literally just did "print,
hash, print, hash, hash, print, hash,

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hash, hash."

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But it's correct.

246
00:12:14,040 --> 00:12:18,490
It does what we told it to,
so you can't take points off.

247
00:12:18,490 --> 00:12:20,487
If you're down to the
wire, obviously, you

248
00:12:20,487 --> 00:12:23,820
want to get a more elegant solution, and
the more elegant solution will probably

249
00:12:23,820 --> 00:12:27,292
be less code, which means you probably
have a higher chance of being right.

250
00:12:27,292 --> 00:12:29,750
But if you're like, you know
what, no, I don't have time, I

251
00:12:29,750 --> 00:12:32,640
know this is a solution,
it's not the best, write it.

252
00:12:32,640 --> 00:12:36,130
And you can even write on the
side, I know this is terrible,

253
00:12:36,130 --> 00:12:38,135
but I know it works.

254
00:12:38,135 --> 00:12:39,320
So just a heads-up.

255
00:12:39,320 --> 00:12:39,820
OK.

256
00:12:39,820 --> 00:12:42,690
>> So obviously, first thing
is this If statement.

257
00:12:42,690 --> 00:12:45,320
So what do we think this If
statement is going to be?

258
00:12:45,320 --> 00:12:50,860
And actually, let me open
up my great Sublime editor.

259
00:12:50,860 --> 00:12:55,480
I'm going to code this and then
show you guys when it's done.

260
00:12:55,480 --> 00:12:57,370
So int pop.

261
00:12:57,370 --> 00:13:02,260

262
00:13:02,260 --> 00:13:03,240
OK.

263
00:13:03,240 --> 00:13:07,330
So if we have this int
pop void-- so obviously,

264
00:13:07,330 --> 00:13:13,270
this is some function that takes in
nothing and returns an integer, right?

265
00:13:13,270 --> 00:13:18,930
So it's just going to talk about
this stack that we've created.

266
00:13:18,930 --> 00:13:23,360
>> So just translating this last
sentence, "if stack is empty,

267
00:13:23,360 --> 00:13:28,380
pop should return negative
1," how might we do that?

268
00:13:28,380 --> 00:13:30,250
So If what?

269
00:13:30,250 --> 00:13:35,080
How do we know that the stack is empty?

270
00:13:35,080 --> 00:13:36,800
It's just size equals 0.

271
00:13:36,800 --> 00:13:40,300
Stack.size equals 0.

272
00:13:40,300 --> 00:13:42,840
Also, I'm kind of writing blind here.

273
00:13:42,840 --> 00:13:49,550
So if I make any typos-- oh,
also forgot to mention this.

274
00:13:49,550 --> 00:13:54,310
>> Last week, I totally figured out
what our problem was with JavaScript.

275
00:13:54,310 --> 00:13:57,270
Don't capitalize I
and D. You should only

276
00:13:57,270 --> 00:14:00,070
capitalize I and get element by Id.

277
00:14:00,070 --> 00:14:02,170
And that was the entire error.

278
00:14:02,170 --> 00:14:05,700
So if you guys go back and
actually look through my code,

279
00:14:05,700 --> 00:14:09,590
if you just make everything a
lowercase d, "forget element by Id,"

280
00:14:09,590 --> 00:14:10,410
it will work.

281
00:14:10,410 --> 00:14:12,823
So as I promised, I was very close.

282
00:14:12,823 --> 00:14:15,570
I just capitalized something
I wasn't supposed to, which

283
00:14:15,570 --> 00:14:19,231
I'm sure you guys had in your last PSET.

284
00:14:19,231 --> 00:14:22,750
>> So if our size equals 0,
what are we supposed to do?

285
00:14:22,750 --> 00:14:25,100
>> AUDIENCE: Return negative 1.

286
00:14:25,100 --> 00:14:28,644
>> SPEAKER 1: Return negative 1.

287
00:14:28,644 --> 00:14:29,450
Cool.

288
00:14:29,450 --> 00:14:33,050
So now what do we do?

289
00:14:33,050 --> 00:14:39,420

290
00:14:39,420 --> 00:14:41,730
We want to pop something off.

291
00:14:41,730 --> 00:14:45,090
Now this is the case
where we have something.

292
00:14:45,090 --> 00:14:48,686
Our size is greater than 1
or greater than 0, right?

293
00:14:48,686 --> 00:14:50,060
We actually have something there.

294
00:14:50,060 --> 00:14:54,390
So what we want to do is we
want to return right here.

295
00:14:54,390 --> 00:14:58,860
We're going to say we want
to return top of stack.

296
00:14:58,860 --> 00:15:00,940
OK?

297
00:15:00,940 --> 00:15:03,840
>> So how might we do that?

298
00:15:03,840 --> 00:15:06,410
How do we return the top of the stack?

299
00:15:06,410 --> 00:15:09,700
Remember, our stack is
just an array, right?

300
00:15:09,700 --> 00:15:12,690
It has some capacity
that we've given it.

301
00:15:12,690 --> 00:15:17,840
As we've put things on-- or actually,
we're going to write "push" after this.

302
00:15:17,840 --> 00:15:21,563
If things are in there--
maybe a picture will help.

303
00:15:21,563 --> 00:15:30,845

304
00:15:30,845 --> 00:15:32,120
Hm, I like big chalk better.

305
00:15:32,120 --> 00:15:35,920

306
00:15:35,920 --> 00:15:41,000
>> So if-- and you can just
think of this as our stack.

307
00:15:41,000 --> 00:15:48,510
So this is 0, 1, 2.

308
00:15:48,510 --> 00:15:51,175
I don't know why my boxes
are getting smaller.

309
00:15:51,175 --> 00:15:52,540
But there.

310
00:15:52,540 --> 00:15:53,180
OK.

311
00:15:53,180 --> 00:15:59,960
>> So this is some stack
with a capacity of 5.

312
00:15:59,960 --> 00:16:04,470
And let's say we have something
here and we have something here.

313
00:16:04,470 --> 00:16:10,840
So at this point, our
size is equal to what?

314
00:16:10,840 --> 00:16:12,720
2.

315
00:16:12,720 --> 00:16:15,370
And if we want to pop
something off of it,

316
00:16:15,370 --> 00:16:18,720
that means we want to get
rid of this right here.

317
00:16:18,720 --> 00:16:21,300
OK?

318
00:16:21,300 --> 00:16:25,633
So how would we return this value?

319
00:16:25,633 --> 00:16:27,397
>> AUDIENCE: Size minus 1.

320
00:16:27,397 --> 00:16:28,230
>> SPEAKER 1: Right.

321
00:16:28,230 --> 00:16:35,010
So size minus 1, or you
could do size minus minus.

322
00:16:35,010 --> 00:16:36,740
But we can't just do size.

323
00:16:36,740 --> 00:16:38,560
It's inside a struct, right?

324
00:16:38,560 --> 00:16:42,690
So stack.struct.

325
00:16:42,690 --> 00:16:44,510
or stack.size.

326
00:16:44,510 --> 00:16:47,100
That's our index right there.

327
00:16:47,100 --> 00:16:48,070
OK?

328
00:16:48,070 --> 00:16:56,240
>> And then if we look
back at our struct here,

329
00:16:56,240 --> 00:16:59,770
we notice that to
actually access the array,

330
00:16:59,770 --> 00:17:04,920
we need to do stack.numbers
to actually access that array.

331
00:17:04,920 --> 00:17:09,859

332
00:17:09,859 --> 00:17:13,700
So that returns the top of the stack.

333
00:17:13,700 --> 00:17:18,950
>> But something that-- if you guys look
at the answer key, this is all they

334
00:17:18,950 --> 00:17:21,470
give you.

335
00:17:21,470 --> 00:17:22,640
So this is it.

336
00:17:22,640 --> 00:17:27,450
But I might argue that they're
miss-- ooh, not what I wanted.

337
00:17:27,450 --> 00:17:30,864
I might argue that they're
missing something, because-- yes.

338
00:17:30,864 --> 00:17:32,030
AUDIENCE: Decrease the size.

339
00:17:32,030 --> 00:17:32,738
SPEAKER 1: Right.

340
00:17:32,738 --> 00:17:34,634
We need to decrease our size now.

341
00:17:34,634 --> 00:17:36,550
So what's tricky about
this is once you return

342
00:17:36,550 --> 00:17:38,780
something, your function's
going exit, right?

343
00:17:38,780 --> 00:17:44,050
So what we might do is actually
decrease our size first.

344
00:17:44,050 --> 00:17:47,110
And then we can just do stack.size.

345
00:17:47,110 --> 00:17:52,110
>> We can just use stack.size
as our index, couldn't we?

346
00:17:52,110 --> 00:17:55,650
Because if stack.size
is 2, we decrement it.

347
00:17:55,650 --> 00:17:58,520
And so it's 1, which
is our actual indice.

348
00:17:58,520 --> 00:18:03,320
Once we get rid of this, we actually
only have one thing in our array.

349
00:18:03,320 --> 00:18:04,204
So it does both.

350
00:18:04,204 --> 00:18:05,120
AUDIENCE: [INAUDIBLE]?

351
00:18:05,120 --> 00:18:09,186

352
00:18:09,186 --> 00:18:14,750
>> SPEAKER 1: Well, in this case,
we just returned the element

353
00:18:14,750 --> 00:18:19,500
at the top that is at our
size that's at the top.

354
00:18:19,500 --> 00:18:25,530
But we haven't done anything to the
size after we removed that element.

355
00:18:25,530 --> 00:18:29,970
This hasn't changed our size yet.

356
00:18:29,970 --> 00:18:32,410
This does actually
inherently change our size.

357
00:18:32,410 --> 00:18:39,840
>> But to make it a little clearer,
you could do stack.size minus minus.

358
00:18:39,840 --> 00:18:46,960
For me, it makes it, I don't know,
a little more clear that-- ah,

359
00:18:46,960 --> 00:18:51,080
that you're actually changing
the size and returning it.

360
00:18:51,080 --> 00:18:54,050
The other way was fine, because
you were changing and returning

361
00:18:54,050 --> 00:18:55,700
at the same time.

362
00:18:55,700 --> 00:19:00,792
But this is just another way to write
it that I wanted to show you guys.

363
00:19:00,792 --> 00:19:02,190
Does that make sense?

364
00:19:02,190 --> 00:19:04,940

365
00:19:04,940 --> 00:19:06,847
Stacks, I think, are
much easier than queues.

366
00:19:06,847 --> 00:19:08,188
[LAUGHS]

367
00:19:08,188 --> 00:19:09,481

368
00:19:09,481 --> 00:19:09,980
OK.

369
00:19:09,980 --> 00:19:12,000
Did you have any specific questions
about 11 and 12, or just--

370
00:19:12,000 --> 00:19:13,736
>> AUDIENCE: I think it was the stack.

371
00:19:13,736 --> 00:19:14,910
>> SPEAKER 1: The stack size?

372
00:19:14,910 --> 00:19:15,430
>> AUDIENCE: Yeah.

373
00:19:15,430 --> 00:19:15,980
>> SPEAKER 1: Gotcha.

374
00:19:15,980 --> 00:19:16,490
OK.

375
00:19:16,490 --> 00:19:19,630
Yeah, you could do it in
one of these two ways.

376
00:19:19,630 --> 00:19:20,320
OK.

377
00:19:20,320 --> 00:19:22,790
>> So now we have the other one.

378
00:19:22,790 --> 00:19:30,250

379
00:19:30,250 --> 00:19:34,220
This is really weird, like
not having this on my screen.

380
00:19:34,220 --> 00:19:46,480

381
00:19:46,480 --> 00:19:51,030
So if we look here, we now want to
complete the implementation of push,

382
00:19:51,030 --> 00:19:57,030
which actually puts something, goes
and inserts something into our queue,

383
00:19:57,030 --> 00:19:59,390
or into our stack.

384
00:19:59,390 --> 00:20:00,140
OK?

385
00:20:00,140 --> 00:20:03,560
>> So if we notice, we
have a couple of things.

386
00:20:03,560 --> 00:20:07,730
We have our great-- if all else,
whenever we have one of these,

387
00:20:07,730 --> 00:20:10,610
you guys should at least get half
a point, because all you have to do

388
00:20:10,610 --> 00:20:15,760
is convert this into C. And
they give you half of it.

389
00:20:15,760 --> 00:20:18,560
So "if a stack is full
or it is negative,

390
00:20:18,560 --> 00:20:20,940
then push should return false."

391
00:20:20,940 --> 00:20:21,890
OK?

392
00:20:21,890 --> 00:20:27,900
>> So we only want positive
integers to be on our stack.

393
00:20:27,900 --> 00:20:28,430
All right?

394
00:20:28,430 --> 00:20:31,135
And this is going to either
return true or false.

395
00:20:31,135 --> 00:20:36,410

396
00:20:36,410 --> 00:20:37,765
So we should [INAUDIBLE] bool.

397
00:20:37,765 --> 00:20:43,000

398
00:20:43,000 --> 00:20:43,660
OK.

399
00:20:43,660 --> 00:20:45,725
So translating.

400
00:20:45,725 --> 00:20:47,146
>> AUDIENCE: [INAUDIBLE].

401
00:20:47,146 --> 00:20:48,318
>> SPEAKER 1: Oh, thanks.

402
00:20:48,318 --> 00:20:49,572
Yeah.

403
00:20:49,572 --> 00:20:52,834
This is why I have you guys.

404
00:20:52,834 --> 00:20:53,810
Int n.

405
00:20:53,810 --> 00:20:54,310
Perfect.

406
00:20:54,310 --> 00:20:56,590
Because we're putting
something on to our stack.

407
00:20:56,590 --> 00:20:58,750
We actually need some number.

408
00:20:58,750 --> 00:20:59,250
OK.

409
00:20:59,250 --> 00:21:05,669
>> So just taking that last line that
they gave us, our kind of corner cases,

410
00:21:05,669 --> 00:21:06,960
what do you think we have here?

411
00:21:06,960 --> 00:21:08,730
Obviously, we're going to have some If.

412
00:21:08,730 --> 00:21:09,520
OK.

413
00:21:09,520 --> 00:21:14,380
So we said, If our stack is
full or if n is negative.

414
00:21:14,380 --> 00:21:18,850
So probably easiest to start
with, so if n is less than 0

415
00:21:18,850 --> 00:21:23,960
or-- remember your nice
AND and OR operators there.

416
00:21:23,960 --> 00:21:27,340
>> How would we check to
see if our stack is full?

417
00:21:27,340 --> 00:21:28,368
What happens?

418
00:21:28,368 --> 00:21:30,080
>> AUDIENCE: Size equal CAPACITY.

419
00:21:30,080 --> 00:21:30,871
>> SPEAKER 1: Exactly.

420
00:21:30,871 --> 00:21:35,430

421
00:21:35,430 --> 00:21:36,817
Perfect.

422
00:21:36,817 --> 00:21:37,316
OK.

423
00:21:37,316 --> 00:21:40,672
And what do we want to do there?

424
00:21:40,672 --> 00:21:41,740
>> AUDIENCE: Return false.

425
00:21:41,740 --> 00:21:43,990
>> SPEAKER 1: Return false.

426
00:21:43,990 --> 00:21:44,960
Perfect.

427
00:21:44,960 --> 00:21:47,000
So halfway there, right?

428
00:21:47,000 --> 00:21:50,370
At the very least, you guys
will have half of this.

429
00:21:50,370 --> 00:21:53,280
So let's think about this.

430
00:21:53,280 --> 00:21:57,100

431
00:21:57,100 --> 00:21:59,030
>> So this is the stack we start with.

432
00:21:59,030 --> 00:22:02,340
We're trying to put
some element on here.

433
00:22:02,340 --> 00:22:05,580
>> We have a size that's
equal to 2 right now.

434
00:22:05,580 --> 00:22:09,060
We have a capacity that equals to 5.

435
00:22:09,060 --> 00:22:13,470
And let's say we have
some n that's equal to 3.

436
00:22:13,470 --> 00:22:18,170
So we need to input 3 into this space.

437
00:22:18,170 --> 00:22:22,320
And we need to input it into index 2.

438
00:22:22,320 --> 00:22:22,820
Right?

439
00:22:22,820 --> 00:22:31,730

440
00:22:31,730 --> 00:22:35,130
>> So how might we do this?

441
00:22:35,130 --> 00:22:46,580
Trying to assign-- we
want to access our array.

442
00:22:46,580 --> 00:22:49,300
So stack.numbers.

443
00:22:49,300 --> 00:22:52,932
But at what indice would
we want this to be?

444
00:22:52,932 --> 00:22:54,408
>> AUDIENCE: [INAUDIBLE].

445
00:22:54,408 --> 00:22:56,806
>> SPEAKER 1: Yeah.

446
00:22:56,806 --> 00:22:57,305
Stack.size.

447
00:22:57,305 --> 00:23:02,720

448
00:23:02,720 --> 00:23:04,830
And we want that to equal n, right?

449
00:23:04,830 --> 00:23:05,752
>> AUDIENCE: [INAUDIBLE].

450
00:23:05,752 --> 00:23:07,710
SPEAKER 1: I was actually
just looking at that.

451
00:23:07,710 --> 00:23:09,865
I think that is wrong.

452
00:23:09,865 --> 00:23:14,564
>> AUDIENCE: Don't you want the
space past the current size?

453
00:23:14,564 --> 00:23:18,842
>> SPEAKER 1: Well, if we look here,
our size at this point is 2.

454
00:23:18,842 --> 00:23:25,600
We want it to go into index 2,
because this is the top of our stack.

455
00:23:25,600 --> 00:23:29,480
So I would say that it
should be stack.size,

456
00:23:29,480 --> 00:23:32,380
and then you would increase stack.size.

457
00:23:32,380 --> 00:23:33,820
Does everyone agree?

458
00:23:33,820 --> 00:23:35,780
I think I agree with that.

459
00:23:35,780 --> 00:23:38,180
You guys can argue
with me if you'd like.

460
00:23:38,180 --> 00:23:40,078
Or not argue, but we can discuss this.

461
00:23:40,078 --> 00:23:42,518
>> AUDIENCE: [INAUDIBLE].

462
00:23:42,518 --> 00:23:47,650
>> SPEAKER 1: Mm-hm, is where it's
open because of zero indexing.

463
00:23:47,650 --> 00:23:50,027
So whereas in the first part,
I thought they were wrong,

464
00:23:50,027 --> 00:23:53,910
and they were actually right, this
part, I actually think they were wrong.

465
00:23:53,910 --> 00:23:55,990
I would say you should
definitely input it here.

466
00:23:55,990 --> 00:23:58,540
I think we all agree
we have a size of 2.

467
00:23:58,540 --> 00:24:01,480
That's exactly where we
want our new number to go.

468
00:24:01,480 --> 00:24:05,120
So stack.numbers at
stack.size should equal n.

469
00:24:05,120 --> 00:24:09,510
And then we would
increment the stack.size.

470
00:24:09,510 --> 00:24:11,099
++.

471
00:24:11,099 --> 00:24:12,390
And then what do we want to do?

472
00:24:12,390 --> 00:24:17,400
There's one last thing we have to
do if we successfully inserted this?

473
00:24:17,400 --> 00:24:19,190
Return true.

474
00:24:19,190 --> 00:24:20,071
And now you're done.

475
00:24:20,071 --> 00:24:23,440

476
00:24:23,440 --> 00:24:27,765
So I feel like it was the whole minus
minus stack.size and stack.size ++ that

477
00:24:27,765 --> 00:24:29,440
messed things up.

478
00:24:29,440 --> 00:24:29,940
Ugh.

479
00:24:29,940 --> 00:24:34,400
I keep-- I have this knee-jerk
tendency to always hit

480
00:24:34,400 --> 00:24:38,060
Control, S, because I never
want to lose any of my work.

481
00:24:38,060 --> 00:24:39,670
But I don't need to do that now.

482
00:24:39,670 --> 00:24:40,170
OK.

483
00:24:40,170 --> 00:24:41,650
So that was stack.

484
00:24:41,650 --> 00:24:44,460

485
00:24:44,460 --> 00:24:46,300
Cool.

486
00:24:46,300 --> 00:24:48,970
>> Is there anything?

487
00:24:48,970 --> 00:24:51,220
Did you guys find any
other questions that you'd

488
00:24:51,220 --> 00:24:52,810
like to go over from previous quizzes?

489
00:24:52,810 --> 00:24:57,660
If not, we can kind of start talking
through Quiz One from last year.

490
00:24:57,660 --> 00:24:58,160
Yes.

491
00:24:58,160 --> 00:25:00,035
>> AUDIENCE: For the first
part, I didn't really

492
00:25:00,035 --> 00:25:02,438
understand how you deleted the number.

493
00:25:02,438 --> 00:25:03,600
Isn't it still there?

494
00:25:03,600 --> 00:25:05,100
>> SPEAKER 1: The number's still there.

495
00:25:05,100 --> 00:25:11,350
But what happens is that because you've
told it that the top of your stack

496
00:25:11,350 --> 00:25:16,180
is here, when you go to add something
onto the stack, it'll just replace it.

497
00:25:16,180 --> 00:25:17,084
>> AUDIENCE: Oh, OK.

498
00:25:17,084 --> 00:25:17,750
SPEAKER 1: Yeah.

499
00:25:17,750 --> 00:25:21,334
So it's like he forgot and it's there
type of thing even though it's there.

500
00:25:21,334 --> 00:25:22,750
AUDIENCE: [INAUDIBLE] or anything?

501
00:25:22,750 --> 00:25:23,333
SPEAKER 1: No.

502
00:25:23,333 --> 00:25:25,090
Because we're in an
array, you don't have

503
00:25:25,090 --> 00:25:28,850
to worry about-- you'll just
override it when you need it.

504
00:25:28,850 --> 00:25:30,560
All right.

505
00:25:30,560 --> 00:25:31,560
Any other questions?

506
00:25:31,560 --> 00:25:34,843
If not, we're just going
to start working through.

507
00:25:34,843 --> 00:25:35,343
Yeah.

508
00:25:35,343 --> 00:25:40,905
>> AUDIENCE: Well, this one is on the 2013,
but just going through the SQL stuff.

509
00:25:40,905 --> 00:25:41,530
SPEAKER 1: SQL?

510
00:25:41,530 --> 00:25:42,030
OK.

511
00:25:42,030 --> 00:25:45,290

512
00:25:45,290 --> 00:25:46,925
So this is 26 through 29.

513
00:25:46,925 --> 00:25:47,550
AUDIENCE: Yeah.

514
00:25:47,550 --> 00:25:48,120
SPEAKER 1: OK.

515
00:25:48,120 --> 00:25:48,620
Lovely.

516
00:25:48,620 --> 00:25:50,230
Let's pull those up.

517
00:25:50,230 --> 00:25:57,560

518
00:25:57,560 --> 00:25:59,506
Oh, look.

519
00:25:59,506 --> 00:26:02,180
Did you guys enjoy the Steve
Ballmer talk, by the way?

520
00:26:02,180 --> 00:26:06,350
It was pretty hilarious, in my opinion.

521
00:26:06,350 --> 00:26:09,930
I love that every time I bring up CS50's
website during section, it's like, oh,

522
00:26:09,930 --> 00:26:10,730
watch section.

523
00:26:10,730 --> 00:26:11,575
And I'm like, mm.

524
00:26:11,575 --> 00:26:13,100
>> AUDIENCE: Can we do it?

525
00:26:13,100 --> 00:26:15,060
>> SPEAKER 1: We'll do it at the end.

526
00:26:15,060 --> 00:26:15,560
How's that?

527
00:26:15,560 --> 00:26:17,476
Because I know you guys
have always wanted to.

528
00:26:17,476 --> 00:26:18,573
So we'll do it at the end.

529
00:26:18,573 --> 00:26:21,884

530
00:26:21,884 --> 00:26:22,800
One questions.

531
00:26:22,800 --> 00:26:24,502
>> AUDIENCE: [INAUDIBLE].

532
00:26:24,502 --> 00:26:25,960
SPEAKER 1: It'll be a meta section.

533
00:26:25,960 --> 00:26:27,332
AUDIENCE: It's like 5 seconds.

534
00:26:27,332 --> 00:26:28,805
AUDIENCE: Really?

535
00:26:28,805 --> 00:26:30,567
AUDIENCE: It's like 20 seconds.

536
00:26:30,567 --> 00:26:33,260
[INTERPOSING VOICES]

537
00:26:33,260 --> 00:26:35,756
[LAUGHTER]

538
00:26:35,756 --> 00:26:35,931

539
00:26:35,931 --> 00:26:37,680
SPEAKER 1: I like that
you've already done

540
00:26:37,680 --> 00:26:40,130
it, which is what makes me happier.

541
00:26:40,130 --> 00:26:42,340
OK.

542
00:26:42,340 --> 00:26:42,840
26.

543
00:26:42,840 --> 00:26:43,340
OK.

544
00:26:43,340 --> 00:26:46,050

545
00:26:46,050 --> 00:26:48,930
Actually, we're just going to
mirror this now, because I can't.

546
00:26:48,930 --> 00:26:49,640
This is annoying.

547
00:26:49,640 --> 00:26:56,200

548
00:26:56,200 --> 00:26:56,700
OK.

549
00:26:56,700 --> 00:27:00,254
Now I can see everything.

550
00:27:00,254 --> 00:27:01,230
Lovely.

551
00:27:01,230 --> 00:27:02,500
OK.

552
00:27:02,500 --> 00:27:07,300
>> So obviously, this should bring back
great memories from [? CSG ?] Finance.

553
00:27:07,300 --> 00:27:09,090
Half of you about have yours graded now.

554
00:27:09,090 --> 00:27:13,370
The other half I will get to
very, very soon, I promise.

555
00:27:13,370 --> 00:27:17,110
>> So we have some SQL table
that's Accounts here.

556
00:27:17,110 --> 00:27:19,830
Probably similar to
your guys' user tables.

557
00:27:19,830 --> 00:27:22,350
And we have some number
that was a PRIMARY key

558
00:27:22,350 --> 00:27:24,750
and represents a
12-digit account number.

559
00:27:24,750 --> 00:27:27,140
And balance is how much money they have.

560
00:27:27,140 --> 00:27:30,530
And the default value is 100.

561
00:27:30,530 --> 00:27:33,470
And they give them $100 any
time they open an account.

562
00:27:33,470 --> 00:27:36,132
I wish my bank did that.

563
00:27:36,132 --> 00:27:37,710
OK.

564
00:27:37,710 --> 00:27:41,110
>> So we want to complete the schema by
specifying next to number in balance

565
00:27:41,110 --> 00:27:43,900
the appropriate SQL type.

566
00:27:43,900 --> 00:27:50,240
So what do you guys think would be
kind of like your knee-jerk reaction

567
00:27:50,240 --> 00:27:51,380
for types for these two?

568
00:27:51,380 --> 00:27:52,180
>> AUDIENCE: Int.

569
00:27:52,180 --> 00:27:53,450
>> SPEAKER 1: An int.

570
00:27:53,450 --> 00:27:54,230
OK.

571
00:27:54,230 --> 00:27:57,490
And then for a balance?

572
00:27:57,490 --> 00:27:57,990
Decimal.

573
00:27:57,990 --> 00:27:58,490
OK.

574
00:27:58,490 --> 00:27:59,830
So decimal's right.

575
00:27:59,830 --> 00:28:01,450
Int is close.

576
00:28:01,450 --> 00:28:08,610
Kind of the big thing is this
underlined 12-digit account number.

577
00:28:08,610 --> 00:28:11,460
Whenever we have something
that's larger than eight digits,

578
00:28:11,460 --> 00:28:15,522
they want you to use big
int, which I think is--

579
00:28:15,522 --> 00:28:18,370

580
00:28:18,370 --> 00:28:21,605
>> AUDIENCE: Is that just SQL?

581
00:28:21,605 --> 00:28:27,290
>> SPEAKER 1: It's the only time I've heard
of it is SQL-- like using a big int.

582
00:28:27,290 --> 00:28:29,330
It's just to give you a
little more precision,

583
00:28:29,330 --> 00:28:33,070
making sure you're not
overflowing type thing.

584
00:28:33,070 --> 00:28:35,910
In all honesty, I think this
is definitely one of the ones

585
00:28:35,910 --> 00:28:38,480
where it's like, oh,
it's meant for people

586
00:28:38,480 --> 00:28:41,090
who have a little more knowledge of SQL.

587
00:28:41,090 --> 00:28:44,710
We never talked about
big ints in your PSET.

588
00:28:44,710 --> 00:28:48,210
So it's kind of like I'm pretty sure
if you put int, it was half credit.

589
00:28:48,210 --> 00:28:51,450
>> And as I said before, there are going
to be some questions that are just

590
00:28:51,450 --> 00:28:55,550
meant to trip you up, so
that not everyone gets 100.

591
00:28:55,550 --> 00:28:58,326
Because of course, there
are some people in CS50

592
00:28:58,326 --> 00:29:00,950
who have been doing this for like
eight years, and you're like,

593
00:29:00,950 --> 00:29:01,741
what are you doing?

594
00:29:01,741 --> 00:29:03,290
But yeah.

595
00:29:03,290 --> 00:29:05,650
>> Decimal for balance was the obvious one.

596
00:29:05,650 --> 00:29:10,910
And then big int for number just because
of that, like, underlined 12-digit.

597
00:29:10,910 --> 00:29:16,760
Whenever anything is in bold or it's
underlined, like, pay attention to it.

598
00:29:16,760 --> 00:29:18,940
We're not doing that just because.

599
00:29:18,940 --> 00:29:20,290
OK.

600
00:29:20,290 --> 00:29:24,400
>> So "suppose that the bank imposes
a $20 monthly fee on all accounts.

601
00:29:24,400 --> 00:29:27,850
With what query could the bank
deduct $20 from every account

602
00:29:27,850 --> 00:29:31,490
even if it results from
some negative balances?"

603
00:29:31,490 --> 00:29:35,220
So let's start simple.

604
00:29:35,220 --> 00:29:39,240
We have four main commands
for SQL, which are?

605
00:29:39,240 --> 00:29:42,620
Do you guys remember the four
big ones that I told you?

606
00:29:42,620 --> 00:29:45,710
>> UPDATE, DELETE, SELECT, and INSERT.

607
00:29:45,710 --> 00:29:46,430
Perfect.

608
00:29:46,430 --> 00:29:46,930
Got it.

609
00:29:46,930 --> 00:29:52,910
So what do we think might
be most useful for this one?

610
00:29:52,910 --> 00:29:54,231
We are-- UPDATE.

611
00:29:54,231 --> 00:29:54,730
Exactly.

612
00:29:54,730 --> 00:29:59,330
So UPDATE, because we're looking
at accounts that already exist.

613
00:29:59,330 --> 00:30:03,570
>> So remember our general
sort of thing is update.

614
00:30:03,570 --> 00:30:06,300
And then what comes after UPDATE?

615
00:30:06,300 --> 00:30:09,780
We have some table
that we're referencing.

616
00:30:09,780 --> 00:30:17,130
So if I pull up Sublime again-- UPDATE.

617
00:30:17,130 --> 00:30:18,820
So this is a general format.

618
00:30:18,820 --> 00:30:20,800
So we have UPDATE table.

619
00:30:20,800 --> 00:30:23,203
And then what's the next thing we have?

620
00:30:23,203 --> 00:30:26,230
>> You can do WHERE.

621
00:30:26,230 --> 00:30:30,530
And then we have some qualifier here.

622
00:30:30,530 --> 00:30:32,300
And then what do we have next?

623
00:30:32,300 --> 00:30:38,020
We have some SET-- something
equal to something.

624
00:30:38,020 --> 00:30:38,870
Blah equals blah.

625
00:30:38,870 --> 00:30:41,859

626
00:30:41,859 --> 00:30:42,400
Updated blah.

627
00:30:42,400 --> 00:30:45,655

628
00:30:45,655 --> 00:30:47,050
Right?

629
00:30:47,050 --> 00:30:52,280
So that's like the general
idea for some update.

630
00:30:52,280 --> 00:30:53,060
OK?

631
00:30:53,060 --> 00:30:56,890
>> So let's start filling this
in with what it should be.

632
00:30:56,890 --> 00:30:59,640
So what table are we talking about?

633
00:30:59,640 --> 00:31:02,190
Accounts.

634
00:31:02,190 --> 00:31:05,360
And then in this case,
what's really cool

635
00:31:05,360 --> 00:31:08,620
is are we talking about specific
users within our account,

636
00:31:08,620 --> 00:31:11,240
or are we talking about all users?

637
00:31:11,240 --> 00:31:12,490
We're talking about all users.

638
00:31:12,490 --> 00:31:16,870
So in that case, we can just
delete this WHERE qualifier.

639
00:31:16,870 --> 00:31:20,500
The WHERE is only when you want
to limit what you're changing.

640
00:31:20,500 --> 00:31:23,500
If you want to change the entire
table, you can just drop that.

641
00:31:23,500 --> 00:31:27,390

642
00:31:27,390 --> 00:31:27,960
OK.

643
00:31:27,960 --> 00:31:29,430
>> So now we're at our SET part.

644
00:31:29,430 --> 00:31:31,514
What do we want to change?

645
00:31:31,514 --> 00:31:33,502
>> AUDIENCE: Balance.

646
00:31:33,502 --> 00:31:34,747
>> SPEAKER 1: Balance.

647
00:31:34,747 --> 00:31:37,080
And we're going to-- how are
we going to change balance?

648
00:31:37,080 --> 00:31:40,230

649
00:31:40,230 --> 00:31:43,370
We have a $20 fee, right?

650
00:31:43,370 --> 00:31:45,210
Minus 20.

651
00:31:45,210 --> 00:31:48,130
And they said it's OK if
we have negative balances.

652
00:31:48,130 --> 00:31:51,630
So in this case, you don't need
to do any further error checking.

653
00:31:51,630 --> 00:31:53,040
OK?

654
00:31:53,040 --> 00:31:56,130
That is literally all you have to do.

655
00:31:56,130 --> 00:31:57,990
Cool?

656
00:31:57,990 --> 00:31:59,260
OK.

657
00:31:59,260 --> 00:32:01,460
>> So let's go through the next one.

658
00:32:01,460 --> 00:32:04,510
"With what SQL query could the
bank retrieve the account numbers

659
00:32:04,510 --> 00:32:08,300
of its richest customers with
balances greater than $1,000?"

660
00:32:08,300 --> 00:32:11,820
If your bank and your richest customers
are just the ones with over $1,000,

661
00:32:11,820 --> 00:32:14,130
I feel like you're
doing something wrong.

662
00:32:14,130 --> 00:32:16,080
Like, how does a bank survive on that?

663
00:32:16,080 --> 00:32:18,930
Like, that interest, not quite enough.

664
00:32:18,930 --> 00:32:20,911
OK.

665
00:32:20,911 --> 00:32:23,660
With this sort of thing, what do
you think, of our four functions,

666
00:32:23,660 --> 00:32:25,970
do you think we're going to use?

667
00:32:25,970 --> 00:32:27,048
SELECT.

668
00:32:27,048 --> 00:32:27,548
Perfect.

669
00:32:27,548 --> 00:32:31,300

670
00:32:31,300 --> 00:32:32,460
SELECT.

671
00:32:32,460 --> 00:32:33,300
OK.

672
00:32:33,300 --> 00:32:40,150
So we're selecting some
identifier FROM table.

673
00:32:40,150 --> 00:32:44,070
And then WHERE condition.

674
00:32:44,070 --> 00:32:46,110
So as we go through
these, I'm just going

675
00:32:46,110 --> 00:32:49,680
to give you guys a general refresher
on the general format of all of these.

676
00:32:49,680 --> 00:32:54,600
>> So we're selecting some sort
of [? thing. ?] In this case,

677
00:32:54,600 --> 00:32:59,050
this is going to be
typically some column.

678
00:32:59,050 --> 00:33:02,870
So in our case, we have number, balance.

679
00:33:02,870 --> 00:33:06,020
In your guys' case, maybe
it was ID, name, password.

680
00:33:06,020 --> 00:33:10,760
Any of those columns, that's
typically what we're selecting.

681
00:33:10,760 --> 00:33:14,785
>> So in this case here, which
kind of column, what identifier

682
00:33:14,785 --> 00:33:17,700
are we pulling from our table?

683
00:33:17,700 --> 00:33:21,020
What does it ask us for?

684
00:33:21,020 --> 00:33:24,510
It asks us for our numbers, right?

685
00:33:24,510 --> 00:33:26,236
The account numbers.

686
00:33:26,236 --> 00:33:30,500
So remember, just number in this case.

687
00:33:30,500 --> 00:33:33,910
If you guys ever had the error, that
bright orange box would come up.

688
00:33:33,910 --> 00:33:37,040
And it was like, unexpected
row in, like, whatever.

689
00:33:37,040 --> 00:33:39,840
That's because you called
your table wrong, right?

690
00:33:39,840 --> 00:33:43,660
So be sure that you are
calling the column correctly.

691
00:33:43,660 --> 00:33:48,670
>> So from table, our table
is called accounts.

692
00:33:48,670 --> 00:33:51,460
Again, make sure you're
referencing your table correctly.

693
00:33:51,460 --> 00:33:52,990
And then what's our condition here?

694
00:33:52,990 --> 00:33:55,672
What are we looking for?

695
00:33:55,672 --> 00:33:56,680
We want our rich people.

696
00:33:56,680 --> 00:33:57,180
Yes.

697
00:33:57,180 --> 00:34:00,580
So balance greater than 1,000.

698
00:34:00,580 --> 00:34:02,020
There you go.

699
00:34:02,020 --> 00:34:03,760
That's your query.

700
00:34:03,760 --> 00:34:06,430
Not too bad, right?

701
00:34:06,430 --> 00:34:07,160
OK.

702
00:34:07,160 --> 00:34:09,350
>> So now for our last one.

703
00:34:09,350 --> 00:34:11,370
With that, we're breezing through.

704
00:34:11,370 --> 00:34:12,170
OK.

705
00:34:12,170 --> 00:34:16,280
So now "with what query could
the bank close, i.e., delete"--

706
00:34:16,280 --> 00:34:19,760
don't you love how they
just gave you DELETE--

707
00:34:19,760 --> 00:34:24,060
"every account that has a balance of 0?"

708
00:34:24,060 --> 00:34:26,899
I think we can all agree we're
probably going to be using DELETE.

709
00:34:26,899 --> 00:34:29,330
I'm welcome to take any
discussion around that.

710
00:34:29,330 --> 00:34:33,560
But I think it's pretty safe to
say that we could use DELETE.

711
00:34:33,560 --> 00:34:42,600
>> So we're going to DELETE some
users from table, WHERE condition.

712
00:34:42,600 --> 00:34:45,480
So same sort of thing as SELECT.

713
00:34:45,480 --> 00:34:48,389

714
00:34:48,389 --> 00:34:49,840
So in this case-- oh, sorry.

715
00:34:49,840 --> 00:34:51,570
I should DELETE FROM.

716
00:34:51,570 --> 00:34:54,320
Because DELETE will
delete the entire row.

717
00:34:54,320 --> 00:34:58,300
So we don't need to talk about which
specific things about a user we're

718
00:34:58,300 --> 00:34:59,280
deleting.

719
00:34:59,280 --> 00:35:02,870
If we delete a user, we're
deleting everything about them.

720
00:35:02,870 --> 00:35:07,230
>> So in this case, we just need to
fill in our WHERE and our condition.

721
00:35:07,230 --> 00:35:13,050
So our table is just our accounts
table, as we've been doing.

722
00:35:13,050 --> 00:35:14,931
And then what is our condition here?

723
00:35:14,931 --> 00:35:16,655
>> AUDIENCE: Balance.

724
00:35:16,655 --> 00:35:18,330
>> SPEAKER 1: Balance equals 0.

725
00:35:18,330 --> 00:35:19,401
Correct.

726
00:35:19,401 --> 00:35:19,900
All good.

727
00:35:19,900 --> 00:35:20,322
Yes.

728
00:35:20,322 --> 00:35:21,238
>> AUDIENCE: [INAUDIBLE].

729
00:35:21,238 --> 00:35:25,745

730
00:35:25,745 --> 00:35:30,530
>> SPEAKER 1: So DELETE
inherently deletes everything.

731
00:35:30,530 --> 00:35:42,380
So whereas with SELECT, SELECT takes in
certain columns that you want returned.

732
00:35:42,380 --> 00:35:46,680
If you wanted everything about
a user returned, you use star.

733
00:35:46,680 --> 00:35:49,040
Star says, return to me
everything from this user.

734
00:35:49,040 --> 00:35:54,430
Or if you put WHERE star, that
means just give me everything.

735
00:35:54,430 --> 00:35:56,520
>> But DELETE inherently has that.

736
00:35:56,520 --> 00:36:01,569
So if you say, DELETE from
accounts where balance equals 0,

737
00:36:01,569 --> 00:36:02,610
it's going to go through.

738
00:36:02,610 --> 00:36:05,890
And everywhere that balance is
equal to 0, it inherently does that.

739
00:36:05,890 --> 00:36:07,470
It'll delete everything.

740
00:36:07,470 --> 00:36:15,120
The star is more for--
with SELECT or UPDATE,

741
00:36:15,120 --> 00:36:20,320
it's talking more about the individual
fields corresponding to a user.

742
00:36:20,320 --> 00:36:25,530
>> So when you do SELECT
star from table WHERE ID

743
00:36:25,530 --> 00:36:31,130
equals 1, that returns to you
everything about the user with ID 1.

744
00:36:31,130 --> 00:36:38,980
If you were to do SELECT number
or SELECT ID comma name from users

745
00:36:38,980 --> 00:36:43,110
WHERE ID equals 1, that
just returns their number

746
00:36:43,110 --> 00:36:44,880
or their ID and their name.

747
00:36:44,880 --> 00:36:45,540
OK?

748
00:36:45,540 --> 00:36:49,420
>> So we use star in that case to
give us everything about a user.

749
00:36:49,420 --> 00:36:51,940
And DELETE inherently does that.

750
00:36:51,940 --> 00:36:56,950
It doesn't just delete the ID,
or just the name, or whatever.

751
00:36:56,950 --> 00:36:57,550
Yeah, no.

752
00:36:57,550 --> 00:36:59,780
It just deletes the entire user.

753
00:36:59,780 --> 00:37:05,210
So we don't have to worry
about the star there.

754
00:37:05,210 --> 00:37:09,170
>> If you wanted to delete
everything, you could do that,

755
00:37:09,170 --> 00:37:11,970
and this'll just drop everything.

756
00:37:11,970 --> 00:37:14,290
But typically, you
don't want to do that.

757
00:37:14,290 --> 00:37:16,940
But if you ever want to delete
everything, you could do that.

758
00:37:16,940 --> 00:37:18,890
OK.

759
00:37:18,890 --> 00:37:22,120
>> Have you guys found any other questions?

760
00:37:22,120 --> 00:37:22,620
Yes.

761
00:37:22,620 --> 00:37:24,316
>> AUDIENCE: Could you do 26?

762
00:37:24,316 --> 00:37:27,090
>> SPEAKER 1: 26 we just did.

763
00:37:27,090 --> 00:37:28,090
AUDIENCE: Oh, 25, sorry.

764
00:37:28,090 --> 00:37:30,721
SPEAKER 1: 25.

765
00:37:30,721 --> 00:37:31,220
OK.

766
00:37:31,220 --> 00:37:31,870
25.

767
00:37:31,870 --> 00:37:32,650
Oh.

768
00:37:32,650 --> 00:37:33,691
They're doing JavaScript.

769
00:37:33,691 --> 00:37:37,265
Oh, I can't believe it.

770
00:37:37,265 --> 00:37:38,765
I'm going to mess us up again, guys.

771
00:37:38,765 --> 00:37:42,180

772
00:37:42,180 --> 00:37:43,330
OK.

773
00:37:43,330 --> 00:37:44,440
We got this.

774
00:37:44,440 --> 00:37:46,172
We're going to make this work.

775
00:37:46,172 --> 00:37:48,190
Ah, jQuery.

776
00:37:48,190 --> 00:37:49,380
Fun.

777
00:37:49,380 --> 00:37:49,880
OK.

778
00:37:49,880 --> 00:37:54,040
>> So we are going to complete the
implementation of the web page

779
00:37:54,040 --> 00:37:57,820
in such a way that if they visit,
input their name, and submit the form,

780
00:37:57,820 --> 00:38:03,810
they have this great alert
window that is going to appear.

781
00:38:03,810 --> 00:38:08,410
So anything with alerts, we know that
we're going to have to use JavaScript.

782
00:38:08,410 --> 00:38:11,190
Yay, JavaScript.

783
00:38:11,190 --> 00:38:14,070
And if they fail to input a
name before submitting the form,

784
00:38:14,070 --> 00:38:15,110
no alert should appear.

785
00:38:15,110 --> 00:38:17,900
So you can use jQuery,
but you don't have to.

786
00:38:17,900 --> 00:38:22,390
>> So I'm going to let you guys work
on this just for a couple minutes.

787
00:38:22,390 --> 00:38:24,050
Think about it.

788
00:38:24,050 --> 00:38:26,050
And then we will code it.

789
00:38:26,050 --> 00:38:29,260

790
00:38:29,260 --> 00:38:33,610
Slash I am going to try and think of the
best way to explain this answer to you.

791
00:38:33,610 --> 00:38:49,945

792
00:38:49,945 --> 00:38:50,470
All right.

793
00:38:50,470 --> 00:38:53,150
We'll get it set up.

794
00:38:53,150 --> 00:38:53,920
OK.

795
00:38:53,920 --> 00:38:56,370
>> So we're just going
to walk through this,

796
00:38:56,370 --> 00:38:59,010
because I know jQuery
is a little confusing.

797
00:38:59,010 --> 00:39:01,710
JavaScript.

798
00:39:01,710 --> 00:39:03,542
It's a little out there.

799
00:39:03,542 --> 00:39:05,875
So what we're going to do is
[INAUDIBLE] actually solved

800
00:39:05,875 --> 00:39:07,250
this problem with jQuery.

801
00:39:07,250 --> 00:39:09,490
So if you remember,
jQuery is just a library

802
00:39:09,490 --> 00:39:11,520
that's just built on top of JavaScript.

803
00:39:11,520 --> 00:39:14,750
It's meant to make your
life a little bit easier.

804
00:39:14,750 --> 00:39:17,660
>> I would definitely, if
you have time, look over

805
00:39:17,660 --> 00:39:20,510
a little bit of the
documentation for jQuery.

806
00:39:20,510 --> 00:39:23,230
But it's very similar to JavaScript.

807
00:39:23,230 --> 00:39:27,830
It's got similar paradigms, where you
use this dot operator to call functions

808
00:39:27,830 --> 00:39:31,720
on objects that you have.

809
00:39:31,720 --> 00:39:36,970
>> So what we have here is for jQuery,
you should always have this sort

810
00:39:36,970 --> 00:39:43,010
of wrapper, which is the
$(document).ready(function) function

811
00:39:43,010 --> 00:39:45,510
in parentheses here.

812
00:39:45,510 --> 00:39:46,070
OK.

813
00:39:46,070 --> 00:39:48,700
So this might be something
you want on your cheat sheet.

814
00:39:48,700 --> 00:39:52,070
Because at the very least, you can
have the wrapper for your jQuery.

815
00:39:52,070 --> 00:39:57,190
And it'll at least get
you part ways there.

816
00:39:57,190 --> 00:40:00,110
>> So in the same way that we
talked a lot about JavaScript,

817
00:40:00,110 --> 00:40:04,560
and we would start by looking
at what we're trying to edit

818
00:40:04,560 --> 00:40:06,150
or what we're trying to change.

819
00:40:06,150 --> 00:40:09,050
And that would typically be the
first thing that we'd put in.

820
00:40:09,050 --> 00:40:18,270
So in this case, if we go back to this
here and we look at our form here,

821
00:40:18,270 --> 00:40:21,790
we have this inputs,
right, this id of inputs.

822
00:40:21,790 --> 00:40:24,780
And we know that based
on our question, we

823
00:40:24,780 --> 00:40:27,970
are either going to throw
an error if this is empty,

824
00:40:27,970 --> 00:40:31,720
or we're going to put
this into an alert, right?

825
00:40:31,720 --> 00:40:36,670
So probably safe to say that we're
going to be dealing with inputs here.

826
00:40:36,670 --> 00:40:41,770
>> jQuery is very similar in that if we
think back to CSS, anything with an ID

827
00:40:41,770 --> 00:40:44,760
we look at with a hash.

828
00:40:44,760 --> 00:40:48,310
Anything with class we
looked at with a dot, right?

829
00:40:48,310 --> 00:40:53,210
So in the same way here, what
we're talking about is inputs.

830
00:40:53,210 --> 00:40:56,920
We saw that inputs is
an ID within our form.

831
00:40:56,920 --> 00:41:00,850
So we're going to refer to it as such.

832
00:41:00,850 --> 00:41:01,653
Inputs.

833
00:41:01,653 --> 00:41:02,460
OK?

834
00:41:02,460 --> 00:41:04,480
>> So when in doubt, even
if you have nowhere,

835
00:41:04,480 --> 00:41:09,100
if you're really unsure about how to
approach this, A, have this wrapper.

836
00:41:09,100 --> 00:41:11,780
So start there with
the wrapper for jQuery.

837
00:41:11,780 --> 00:41:16,330
B, make sure that you know
what you are changing.

838
00:41:16,330 --> 00:41:18,830
And when in doubt,
put that in something,

839
00:41:18,830 --> 00:41:21,390
and do dot, whatever you think
you should be doing with it.

840
00:41:21,390 --> 00:41:22,150
>> AUDIENCE: What is the wrapper?

841
00:41:22,150 --> 00:41:24,160
>> SPEAKER 1: The wrapper
is this first line.

842
00:41:24,160 --> 00:41:27,520
So this says, wait until
my document is ready.

843
00:41:27,520 --> 00:41:29,160
Then start messing with things.

844
00:41:29,160 --> 00:41:30,890
OK?

845
00:41:30,890 --> 00:41:32,780
So we know we're messing with inputs.

846
00:41:32,780 --> 00:41:35,450
So we're like, OK, inputs is our form.

847
00:41:35,450 --> 00:41:37,220
That's our ID.

848
00:41:37,220 --> 00:41:39,800
So that's what we're
going to be looking for.

849
00:41:39,800 --> 00:41:45,220
And we want to see what happens
when this form is submitted, right?

850
00:41:45,220 --> 00:41:50,180
>> So as we might think,
we have some .submit.

851
00:41:50,180 --> 00:41:56,080
So .submit just says, OK, this form
that we've referenced with hash inputs,

852
00:41:56,080 --> 00:41:59,594
when it's submitted,
execute something else.

853
00:41:59,594 --> 00:42:01,135
So we're going to have some function.

854
00:42:01,135 --> 00:42:05,010

855
00:42:05,010 --> 00:42:07,270
Notice we have anonymous functions here.

856
00:42:07,270 --> 00:42:09,090
We have an anonymous function here.

857
00:42:09,090 --> 00:42:09,590
Yes.

858
00:42:09,590 --> 00:42:14,880
>> AUDIENCE: Will it always be .submit,
or is it just because in the HTML,

859
00:42:14,880 --> 00:42:18,260
we made the button type Submit?

860
00:42:18,260 --> 00:42:23,680
>> SPEAKER 1: It should be .submit, because
it's some form that we are submitting.

861
00:42:23,680 --> 00:42:27,750
Because this .submit doesn't necessarily
correspond to what the button is like

862
00:42:27,750 --> 00:42:28,430
to call.

863
00:42:28,430 --> 00:42:32,610
But the fact that it's a
form that we're submitting.

864
00:42:32,610 --> 00:42:33,140
OK.

865
00:42:33,140 --> 00:42:35,015
>> So notice anonymous
function here that says--

866
00:42:35,015 --> 00:42:37,348
AUDIENCE: I don't really
understand anonymous functions.

867
00:42:37,348 --> 00:42:39,240
SPEAKER 1: So anonymous
functions, they're

868
00:42:39,240 --> 00:42:42,380
just functions that don't have a name.

869
00:42:42,380 --> 00:42:49,560
So instead of having some main function
that calls-- we could say, If document

870
00:42:49,560 --> 00:42:52,380
ready, then we would call inputs.

871
00:42:52,380 --> 00:42:57,470
And then, When submitted, call--
like, If so-and-so submitted,

872
00:42:57,470 --> 00:42:59,550
we'd call some other function.

873
00:42:59,550 --> 00:43:01,840
An anonymous function
just doesn't have a name,

874
00:43:01,840 --> 00:43:05,120
and it will just execute
within these sorts of things.

875
00:43:05,120 --> 00:43:10,970
>> So in this case, what this says
is, When our document is ready,

876
00:43:10,970 --> 00:43:12,880
execute this function.

877
00:43:12,880 --> 00:43:17,110
This function is composed
of everything within here.

878
00:43:17,110 --> 00:43:24,410
And then the next layer in is, OK,
when inputs is submitted, execute this.

879
00:43:24,410 --> 00:43:28,329
It's just a way of denoting
what should be executed when.

880
00:43:28,329 --> 00:43:30,120
It's literally just a
function that doesn't

881
00:43:30,120 --> 00:43:32,860
have a name, so they tend to
be nested into each other,

882
00:43:32,860 --> 00:43:35,132
because you can't call them by name.

883
00:43:35,132 --> 00:43:36,984
OK?

884
00:43:36,984 --> 00:43:39,775
Literally, an anonymous function
is just a function without a name.

885
00:43:39,775 --> 00:43:41,470
That's it.

886
00:43:41,470 --> 00:43:47,370
Just a way to encapsulate
different things

887
00:43:47,370 --> 00:43:49,250
that we want executed at specific times.

888
00:43:49,250 --> 00:43:51,164
>> AUDIENCE: [INAUDIBLE].

889
00:43:51,164 --> 00:43:53,420
>> SPEAKER 1: The vent?

890
00:43:53,420 --> 00:43:54,360
Where?

891
00:43:54,360 --> 00:43:57,510
>> AUDIENCE: In the
parentheses after function?

892
00:43:57,510 --> 00:44:00,660
>> SPEAKER 1: After functions.

893
00:44:00,660 --> 00:44:01,290
Which one?

894
00:44:01,290 --> 00:44:02,410
>> AUDIENCE: Both.

895
00:44:02,410 --> 00:44:05,137
If you put, like, event, or if
you put an argument in there,

896
00:44:05,137 --> 00:44:07,372
would it be wrong?

897
00:44:07,372 --> 00:44:12,592
>> SPEAKER 1: In this case, I suppose
you could put an argument in there.

898
00:44:12,592 --> 00:44:15,619
But because we don't need an
argument, there shouldn't be.

899
00:44:15,619 --> 00:44:17,410
Like, it's the whole,
like, you should only

900
00:44:17,410 --> 00:44:19,810
have things that are
necessary sort of thing.

901
00:44:19,810 --> 00:44:29,325
In the same way that if we had any
function that has int main void-- like,

902
00:44:29,325 --> 00:44:35,687
with int main void, you
could do int arg v, whatever.

903
00:44:35,687 --> 00:44:38,270
But if you don't need those, you
shouldn't have them in there.

904
00:44:38,270 --> 00:44:39,070
Same thing.

905
00:44:39,070 --> 00:44:40,896
Emma, did you have a question?

906
00:44:40,896 --> 00:44:41,671
OK.

907
00:44:41,671 --> 00:44:42,170
Cool.

908
00:44:42,170 --> 00:44:42,670
OK.

909
00:44:42,670 --> 00:44:45,862
So what we have so far is when our
document's ready, execute this.

910
00:44:45,862 --> 00:44:47,570
Now we're looking at
when it's submitted.

911
00:44:47,570 --> 00:44:51,530
So now we actually have sort
of the meat of our thing.

912
00:44:51,530 --> 00:45:00,120
So we need to get the value that the
user submitted, whether that be a name

913
00:45:00,120 --> 00:45:01,340
or empty.

914
00:45:01,340 --> 00:45:07,270
And then we need to either return
this alert or throw an error.

915
00:45:07,270 --> 00:45:08,560
Either way.

916
00:45:08,560 --> 00:45:13,690
>> So how do we declare a
variable in JavaScript?

917
00:45:13,690 --> 00:45:14,670
Var.

918
00:45:14,670 --> 00:45:19,430
So let's say, var name
equals-- or actually, we'll

919
00:45:19,430 --> 00:45:21,960
do value since I think it's name.

920
00:45:21,960 --> 00:45:23,920
OK.

921
00:45:23,920 --> 00:45:31,320
So we have some value here that we
want to pull from our inputs form.

922
00:45:31,320 --> 00:45:34,100
So in the same way that
we kind of did inputs,

923
00:45:34,100 --> 00:45:38,380
can anyone tell me what we
might be calling within here

924
00:45:38,380 --> 00:45:41,230
if we wanted to get
the name from the form?

925
00:45:41,230 --> 00:45:46,929
And if we look back at our form here,
we notice that we have an ID of name.

926
00:45:46,929 --> 00:45:47,845
AUDIENCE: [INAUDIBLE].

927
00:45:47,845 --> 00:45:51,026

928
00:45:51,026 --> 00:45:54,675
>> SPEAKER 1: You don't have
to think of it as an array.

929
00:45:54,675 --> 00:45:57,650

930
00:45:57,650 --> 00:46:00,760
You don't need to worry about that.

931
00:46:00,760 --> 00:46:03,250
So we just have some name.

932
00:46:03,250 --> 00:46:09,022
And then because JavaScript and things
are weird, we can't just do "name."

933
00:46:09,022 --> 00:46:11,230
We actually have to call
some function that gives us,

934
00:46:11,230 --> 00:46:14,160
like, the value of that identifier.

935
00:46:14,160 --> 00:46:15,160
OK?

936
00:46:15,160 --> 00:46:16,780
So that is just .val.

937
00:46:16,780 --> 00:46:18,356
>> AUDIENCE: [INAUDIBLE].

938
00:46:18,356 --> 00:46:19,160
>> SPEAKER 1: OK.

939
00:46:19,160 --> 00:46:27,030
So with JavaScript, this sort of
thing right here just goes through.

940
00:46:27,030 --> 00:46:35,730
And you could think of this as-- it's
like almost a getElementById, where

941
00:46:35,730 --> 00:46:40,630
getElementById would actually
return the full thing to you.

942
00:46:40,630 --> 00:46:49,930
The $("#name") is just like,
OK, I have it, I can access it,

943
00:46:49,930 --> 00:46:52,265
but if you actually want it
to return the value to you--

944
00:46:52,265 --> 00:46:53,596
>> AUDIENCE: Is it like a pointer?

945
00:46:53,596 --> 00:46:55,070
>> SPEAKER 1: It's kind of like a pointer.

946
00:46:55,070 --> 00:46:57,069
You could think of it as
kind of like a pointer.

947
00:46:57,069 --> 00:46:59,060
Like, it says, OK, I
know how to get there,

948
00:46:59,060 --> 00:47:02,330
but to actually get the value out of
it, you have to explicitly ask for it.

949
00:47:02,330 --> 00:47:07,800
And unfortunately, obviously, we don't
do too much with JavaScript and jQuery.

950
00:47:07,800 --> 00:47:12,160
>> So it's going to come down to how much
you guys-- what you happen to know,

951
00:47:12,160 --> 00:47:17,610
what you happen to have seen, and what
you can kind of logically guess at.

952
00:47:17,610 --> 00:47:21,639
Because some of these things, you
could probably get halfway there.

953
00:47:21,639 --> 00:47:24,180
But to get it completely right,
I think this problem probably

954
00:47:24,180 --> 00:47:25,624
had one of the lowest scores.

955
00:47:25,624 --> 00:47:27,790
AUDIENCE: Like, for example,
for [INAUDIBLE] inputs,

956
00:47:27,790 --> 00:47:29,450
why don't you have to put val there?

957
00:47:29,450 --> 00:47:30,450
SPEAKER 1: For this one?

958
00:47:30,450 --> 00:47:31,124
AUDIENCE: Yeah.

959
00:47:31,124 --> 00:47:31,790
SPEAKER 1: Yeah.

960
00:47:31,790 --> 00:47:33,498
Because this is kind
of like, as we said,

961
00:47:33,498 --> 00:47:37,180
some pointer, and this is me referencing
it and actually getting us the value.

962
00:47:37,180 --> 00:47:38,872
>> AUDIENCE: Whereas [INAUDIBLE]?

963
00:47:38,872 --> 00:47:42,060
>> SPEAKER 1: For inputs,
inputs is just some--

964
00:47:42,060 --> 00:47:44,450
it's like we're just
looking at it as a whole,

965
00:47:44,450 --> 00:47:48,859
and this .submit tells
us what we need to know.

966
00:47:48,859 --> 00:47:50,150
jQuery and JavaScript is weird.

967
00:47:50,150 --> 00:47:50,800
I know.

968
00:47:50,800 --> 00:47:51,690
I know, guys.

969
00:47:51,690 --> 00:47:52,460
I know.

970
00:47:52,460 --> 00:47:55,260
There's a reason I don't
do web programming.

971
00:47:55,260 --> 00:47:56,230
Just kidding.

972
00:47:56,230 --> 00:47:57,780
I haven't had enough exposure to it.

973
00:47:57,780 --> 00:47:59,070
>> AUDIENCE: [INAUDIBLE] CSS.

974
00:47:59,070 --> 00:48:00,206
>> [LAUGHTER]

975
00:48:00,206 --> 00:48:00,590
>> SPEAKER 1: OK, that's CSS.

976
00:48:00,590 --> 00:48:03,730
CSS is just, like, make things pretty,
it's not like let's deal with data.

977
00:48:03,730 --> 00:48:05,710
There's a difference there.

978
00:48:05,710 --> 00:48:06,350
OK.

979
00:48:06,350 --> 00:48:12,110
So now hopefully, this part-- also, for
a problem like this, where you may not

980
00:48:12,110 --> 00:48:16,070
know the syntax, you could be like,
OK, you could have some var value

981
00:48:16,070 --> 00:48:18,320
and be like, assume I
got the value correctly.

982
00:48:18,320 --> 00:48:20,600
And then you could probably
write this next part.

983
00:48:20,600 --> 00:48:24,640
This next part will probably
seem much more easy,

984
00:48:24,640 --> 00:48:26,610
or it would make logical
sense to you guys.

985
00:48:26,610 --> 00:48:31,520
>> Whereas what we've written so far,
I know I would be like, umm, yeah,

986
00:48:31,520 --> 00:48:34,340
I don't know that on the quiz.

987
00:48:34,340 --> 00:48:37,610
You can totally write psuedocode
and then break into real code

988
00:48:37,610 --> 00:48:40,460
when you-- it's kind of like math.

989
00:48:40,460 --> 00:48:42,904
If you've ever had some
multi-part problem where

990
00:48:42,904 --> 00:48:44,820
you don't know how to
get past the first step,

991
00:48:44,820 --> 00:48:46,736
but everything else
relies on that first step,

992
00:48:46,736 --> 00:48:49,577
you just say, like, assume x equals 4.

993
00:48:49,577 --> 00:48:50,910
And then you run with it, right?

994
00:48:50,910 --> 00:48:52,410
>> You can do the same thing with code.

995
00:48:52,410 --> 00:48:55,740
So you could say, assume
I got the value right.

996
00:48:55,740 --> 00:48:58,290
Then do this next part here.

997
00:48:58,290 --> 00:49:02,610
Because this part actually
should be pretty logical.

998
00:49:02,610 --> 00:49:06,560
>> So we need to check
if our value is empty.

999
00:49:06,560 --> 00:49:11,650
Or if it's some name,
actually give an alert.

1000
00:49:11,650 --> 00:49:15,085
So what might we want to check?

1001
00:49:15,085 --> 00:49:17,800
We want to have some If.

1002
00:49:17,800 --> 00:49:19,510
What do you think our If is going to be?

1003
00:49:19,510 --> 00:49:24,141
We need to check to see if value
is-- if it's not an empty string.

1004
00:49:24,141 --> 00:49:30,740

1005
00:49:30,740 --> 00:49:31,730
>> Perfect.

1006
00:49:31,730 --> 00:49:32,570
Exactly.

1007
00:49:32,570 --> 00:49:33,070
OK.

1008
00:49:33,070 --> 00:49:36,320
So if that's the case,
what do we want to do?

1009
00:49:36,320 --> 00:49:39,190
We want to throw some alert, right?

1010
00:49:39,190 --> 00:49:41,090
So it's just alert.

1011
00:49:41,090 --> 00:49:43,050
And then whatever we want inside.

1012
00:49:43,050 --> 00:49:45,430
So what are we supposed
to have inside our alert?

1013
00:49:45,430 --> 00:49:48,916
>> AUDIENCE: "Hello."

1014
00:49:48,916 --> 00:49:50,421
>> SPEAKER 1: Comma.

1015
00:49:50,421 --> 00:49:52,462
And then do you guys
remember how to concatenate?

1016
00:49:52,462 --> 00:49:53,400
>> AUDIENCE: Plus.

1017
00:49:53,400 --> 00:49:54,520
>> SPEAKER 1: Plus.

1018
00:49:54,520 --> 00:49:57,490
So we want to have plus.

1019
00:49:57,490 --> 00:50:03,480
And then we need another plus
for our exclamation point.

1020
00:50:03,480 --> 00:50:05,620
Cool.

1021
00:50:05,620 --> 00:50:06,540
OK.

1022
00:50:06,540 --> 00:50:08,255
Otherwise, what might we want to do?

1023
00:50:08,255 --> 00:50:10,380
We don't want to do anything, right?

1024
00:50:10,380 --> 00:50:14,190
So we just return false.

1025
00:50:14,190 --> 00:50:17,200
Not what I want to do.

1026
00:50:17,200 --> 00:50:18,520
OK.

1027
00:50:18,520 --> 00:50:20,660
>> And then these, of
course-- what's important

1028
00:50:20,660 --> 00:50:23,510
is to remember to close
your anonymous functions.

1029
00:50:23,510 --> 00:50:27,230
So if you notice, we have some
function here that ends here.

1030
00:50:27,230 --> 00:50:31,710
So we need to close this
first one and add a semicolon.

1031
00:50:31,710 --> 00:50:35,195
And then this one here has to
do with this anonymous function,

1032
00:50:35,195 --> 00:50:38,650
so we close it there.

1033
00:50:38,650 --> 00:50:40,190
That knee-jerk reaction of saving.

1034
00:50:40,190 --> 00:50:40,690
Yes.

1035
00:50:40,690 --> 00:50:45,650
AUDIENCE: Is there a reason that--
just in all the examples in JavaScript

1036
00:50:45,650 --> 00:50:48,480
that I've seen, we have
the first curly braces

1037
00:50:48,480 --> 00:50:51,075
on the same line as the function?

1038
00:50:51,075 --> 00:50:53,040
>> SPEAKER 1: That's stylistic.

1039
00:50:53,040 --> 00:50:54,130
Yeah.

1040
00:50:54,130 --> 00:51:00,650
And actually, if you take 61, we
do all our curly braces that way.

1041
00:51:00,650 --> 00:51:01,830
Huh?

1042
00:51:01,830 --> 00:51:05,030
>> AUDIENCE: If we did do that on
the PSET, is that bad for style?

1043
00:51:05,030 --> 00:51:05,720
>> SPEAKER 1: No.

1044
00:51:05,720 --> 00:51:09,710
We have explicitly told
you guys to do this.

1045
00:51:09,710 --> 00:51:14,540
But actually, this is kind
of the dominating convention

1046
00:51:14,540 --> 00:51:19,620
in a lot of C classes and
JavaScript and jQuery.

1047
00:51:19,620 --> 00:51:23,074
So obviously, I'm sure--
and actually, if I

1048
00:51:23,074 --> 00:51:26,770
were to do this problem completely
blind without having looked at it,

1049
00:51:26,770 --> 00:51:30,080
there is probably very few
ways I would have gotten this.

1050
00:51:30,080 --> 00:51:36,160
>> I might have been like, OK, maybe I
need to grab something that's an input.

1051
00:51:36,160 --> 00:51:38,020
And I think having the
knowledge that, like,

1052
00:51:38,020 --> 00:51:43,240
OK, if I want to get something
from a form that has an ID,

1053
00:51:43,240 --> 00:51:46,990
I refer to it in this way,
I'd probably get that.

1054
00:51:46,990 --> 00:51:49,940
I might get this.

1055
00:51:49,940 --> 00:51:53,400
But really, the only thing that I think
I would really get is this right here.

1056
00:51:53,400 --> 00:51:59,230
>> So it's kind of important to
know, as with any difficult test,

1057
00:51:59,230 --> 00:52:02,130
you kind of choose your battles, right?

1058
00:52:02,130 --> 00:52:06,780
If you know that you're not going to get
that first part for jQuery, as I said,

1059
00:52:06,780 --> 00:52:10,080
assume that you have this value
and do what you can with it.

1060
00:52:10,080 --> 00:52:14,730
And if you have time, go back
and try and fill in the pieces.

1061
00:52:14,730 --> 00:52:17,150
But don't let a question like
this really bog you down.

1062
00:52:17,150 --> 00:52:18,080
Because what?

1063
00:52:18,080 --> 00:52:23,260
This was one question on
jQuery out of the entire exam.

1064
00:52:23,260 --> 00:52:25,810
So yes, it'd be great if you got it.

1065
00:52:25,810 --> 00:52:28,297
>> AUDIENCE: [INAUDIBLE] you
are welcome to use jQuery.

1066
00:52:28,297 --> 00:52:30,005
SPEAKER 1: You are
welcome to use jQuery.

1067
00:52:30,005 --> 00:52:31,088
AUDIENCE: OK. [INAUDIBLE].

1068
00:52:31,088 --> 00:52:33,060
SPEAKER 1: How would you not use it?

1069
00:52:33,060 --> 00:52:35,850
I would have to look
up all my JavaScript.

1070
00:52:35,850 --> 00:52:38,810
It's actually much easier,
I think, to use jQuery,

1071
00:52:38,810 --> 00:52:42,995
because jQuery actually reduces the
amount of JavaScript you write probably

1072
00:52:42,995 --> 00:52:43,620
by, like, half.

1073
00:52:43,620 --> 00:52:46,334
So our code would probably be
twice as long without that.

1074
00:52:46,334 --> 00:52:49,250
So if you recognize-- the biggest
thing to take away from this problem

1075
00:52:49,250 --> 00:52:50,550
are the patterns.

1076
00:52:50,550 --> 00:52:52,890
If you're accessing
something from a form,

1077
00:52:52,890 --> 00:52:57,830
you're going to use quotes, hash,
whatever you're trying to access.

1078
00:52:57,830 --> 00:53:01,000
If it's being submitted, you want
to use something like a .submit.

1079
00:53:01,000 --> 00:53:03,680
You're probably going to use
an anonymous function in there.

1080
00:53:03,680 --> 00:53:08,030
If you actually need the value of
something, you're going to do quotes,

1081
00:53:08,030 --> 00:53:12,160
hash, whatever that field is, .val.

1082
00:53:12,160 --> 00:53:14,690
And recognizing patterns
like that are going

1083
00:53:14,690 --> 00:53:19,586
to be far more useful than
really knowing the nitty gritty.

1084
00:53:19,586 --> 00:53:20,562
Yes.

1085
00:53:20,562 --> 00:53:23,164
>> AUDIENCE: So if the
user submits their name

1086
00:53:23,164 --> 00:53:27,394
and it runs through that statement, will
it go down and return false after this?

1087
00:53:27,394 --> 00:53:30,373
>> SPEAKER 1: No, because the alert,
you can think of it like a return.

1088
00:53:30,373 --> 00:53:30,873
Yeah.

1089
00:53:30,873 --> 00:53:31,590
So it'll exit.

1090
00:53:31,590 --> 00:53:31,925
Yeah.

1091
00:53:31,925 --> 00:53:33,883
>> AUDIENCE: Could you
[? place ?] the parentheses

1092
00:53:33,883 --> 00:53:37,105
of submit, parentheses, something?

1093
00:53:37,105 --> 00:53:38,870
>> SPEAKER 1: I did, I believe.

1094
00:53:38,870 --> 00:53:42,300
This one's closed right here.

1095
00:53:42,300 --> 00:53:45,800
And then this one gets closed down here.

1096
00:53:45,800 --> 00:53:47,135
>> AUDIENCE: Oh, there.

1097
00:53:47,135 --> 00:53:48,470
All right.

1098
00:53:48,470 --> 00:53:53,572
>> SPEAKER 1: Obviously, little,
little syntactic things

1099
00:53:53,572 --> 00:53:55,780
like that, we'll probably
just circle it and be like,

1100
00:53:55,780 --> 00:53:58,385
don't forget your parentheses.

1101
00:53:58,385 --> 00:53:59,810
But yeah.

1102
00:53:59,810 --> 00:54:00,950
OK.

1103
00:54:00,950 --> 00:54:04,190
Do we have another one
that we would like to do?

1104
00:54:04,190 --> 00:54:07,700

1105
00:54:07,700 --> 00:54:11,599
Did you guys get the binary tree one?

1106
00:54:11,599 --> 00:54:12,890
Do we want to go over that one?

1107
00:54:12,890 --> 00:54:17,940
I feel like binary trees
and DOMs should be points

1108
00:54:17,940 --> 00:54:19,880
that you guys get pretty easily.

1109
00:54:19,880 --> 00:54:21,978
I would not want you
to lose points on that.

1110
00:54:21,978 --> 00:54:28,335

1111
00:54:28,335 --> 00:54:30,370
OK.

1112
00:54:30,370 --> 00:54:33,097
>> Let's do this DOM here.

1113
00:54:33,097 --> 00:54:35,555
I wish I had my Surface so I
could just draw on the screen.

1114
00:54:35,555 --> 00:54:38,330

1115
00:54:38,330 --> 00:54:41,461
That's what I used to do last year.

1116
00:54:41,461 --> 00:54:41,960
OK.

1117
00:54:41,960 --> 00:54:48,370
So as I mentioned, we talked
about DOM, Document Object Model.

1118
00:54:48,370 --> 00:54:51,415
They're probably going to give you
some little bit of snippet like this

1119
00:54:51,415 --> 00:54:54,250
and ask you to create a tree for it.

1120
00:54:54,250 --> 00:54:58,050
And this just all has to do
with running through the tags.

1121
00:54:58,050 --> 00:55:00,685
So let's try and do this.

1122
00:55:00,685 --> 00:55:09,610

1123
00:55:09,610 --> 00:55:12,920
>> Also, as per usual, if you guys
do these quizzes, as I highly

1124
00:55:12,920 --> 00:55:16,450
recommend that you do as practice,
any of them that you're like,

1125
00:55:16,450 --> 00:55:19,480
I really don't get what's
going on here, just, of course,

1126
00:55:19,480 --> 00:55:23,334
send me an email with a question,
and I will explain as best I can.

1127
00:55:23,334 --> 00:55:25,298
OK.

1128
00:55:25,298 --> 00:55:33,420
>> We have some document, and we have HTML.

1129
00:55:33,420 --> 00:55:33,970
OK.

1130
00:55:33,970 --> 00:55:38,750
So then we're just analysing
the tags here, right?

1131
00:55:38,750 --> 00:55:45,810
So what do we see comes-- what are
the two subheadings under HTML?

1132
00:55:45,810 --> 00:55:48,880
Especially because
they're indented properly?

1133
00:55:48,880 --> 00:55:49,580
Head and body.

1134
00:55:49,580 --> 00:56:00,298

1135
00:56:00,298 --> 00:56:00,800
Ah.

1136
00:56:00,800 --> 00:56:03,730

1137
00:56:03,730 --> 00:56:04,960
Head and body.

1138
00:56:04,960 --> 00:56:05,952
Lovely.

1139
00:56:05,952 --> 00:56:07,410
So then let's start here with head.

1140
00:56:07,410 --> 00:56:09,090
What's underneath head?

1141
00:56:09,090 --> 00:56:11,721
What's our next tag?

1142
00:56:11,721 --> 00:56:12,220
Title.

1143
00:56:12,220 --> 00:56:16,450

1144
00:56:16,450 --> 00:56:19,605
And then within title, quiz.

1145
00:56:19,605 --> 00:56:23,970

1146
00:56:23,970 --> 00:56:24,690
OK.

1147
00:56:24,690 --> 00:56:27,940
>> So literally, it's just
walking through the tags, OK?

1148
00:56:27,940 --> 00:56:31,610
So then if we have
body, as we go through,

1149
00:56:31,610 --> 00:56:35,460
body has three things within it, right?

1150
00:56:35,460 --> 00:56:36,400
It's got three divs.

1151
00:56:36,400 --> 00:56:40,060

1152
00:56:40,060 --> 00:56:41,900
Every div gets its own little box.

1153
00:56:41,900 --> 00:56:45,260

1154
00:56:45,260 --> 00:56:48,106
And what's in the first div?

1155
00:56:48,106 --> 00:56:48,606
[INAUDIBLE]

1156
00:56:48,606 --> 00:56:52,070

1157
00:56:52,070 --> 00:56:57,292
And then the next one is middle,
which I'm just going to abbreviate.

1158
00:56:57,292 --> 00:56:59,410
And then the last one is bottom.

1159
00:56:59,410 --> 00:57:06,060

1160
00:57:06,060 --> 00:57:07,650
>> So really, it's just walking through.

1161
00:57:07,650 --> 00:57:11,140
And because we're going to give
you HTML that is properly indented,

1162
00:57:11,140 --> 00:57:16,800
you can literally just run through
and be like, OK, here is the HTML.

1163
00:57:16,800 --> 00:57:19,460
So this is the outermost
corner, or furthest left,

1164
00:57:19,460 --> 00:57:22,410
so that has to be its own thing.

1165
00:57:22,410 --> 00:57:26,360
These are on the same indention.

1166
00:57:26,360 --> 00:57:30,120
>> So we know that head needs to
be at the same level as body,

1167
00:57:30,120 --> 00:57:32,040
but underneath HTML.

1168
00:57:32,040 --> 00:57:33,100
It's what we have here.

1169
00:57:33,100 --> 00:57:36,810
Head and body are siblings,
but they're under HTML.

1170
00:57:36,810 --> 00:57:39,130
And then we just go into each of these.

1171
00:57:39,130 --> 00:57:44,370
So head has title, which
has quiz, as we see here.

1172
00:57:44,370 --> 00:57:48,210
And then in this case, we have
body, which has these three lines.

1173
00:57:48,210 --> 00:57:51,470
So these are all
siblings all under body.

1174
00:57:51,470 --> 00:57:53,732
OK?

1175
00:57:53,732 --> 00:57:56,190
So hopefully when you see
something like this, you're like,

1176
00:57:56,190 --> 00:57:57,900
yes, I just get to draw a tree.

1177
00:57:57,900 --> 00:58:00,430
It's gonna be great.

1178
00:58:00,430 --> 00:58:01,130
OK.

1179
00:58:01,130 --> 00:58:03,220
So wanted to make sure
you guys knew that.

1180
00:58:03,220 --> 00:58:10,510
>> So why don't we go to
32 with our binary tree?

1181
00:58:10,510 --> 00:58:17,905
Because once you understand a binary
search tree, it's really not that bad.

1182
00:58:17,905 --> 00:58:20,960
So Everett, can I erase-- I
mean, these are all online, too.

1183
00:58:20,960 --> 00:58:24,130
So if you have any questions.

1184
00:58:24,130 --> 00:58:44,410

1185
00:58:44,410 --> 00:58:46,370
>> Lost a little space there, but it's OK.

1186
00:58:46,370 --> 00:58:50,190
So binary search tree is
just a way to organize data

1187
00:58:50,190 --> 00:58:57,000
not in an array, where
the root is always greater

1188
00:58:57,000 --> 00:59:03,500
than the left child and the root is
always less than the right child.

1189
00:59:03,500 --> 00:59:04,770
OK.

1190
00:59:04,770 --> 00:59:08,160
>> So we have this great search tree here.

1191
00:59:08,160 --> 00:59:13,360
We have these numbers, 34,
59, 20, 106, 36, and 52.

1192
00:59:13,360 --> 00:59:15,160
And we need to organize
them in such a way

1193
00:59:15,160 --> 00:59:22,100
such that the root is greater
than everything on the left side

1194
00:59:22,100 --> 00:59:24,750
and it is less than
everything on the right side.

1195
00:59:24,750 --> 00:59:29,580
And typically, what you
want to do is try and find

1196
00:59:29,580 --> 00:59:31,720
something about in the middle.

1197
00:59:31,720 --> 00:59:35,420
With binary search trees, you might have
to play around a little bit with it.

1198
00:59:35,420 --> 00:59:40,850
>> But in this case, let's just
assume that we know this first one.

1199
00:59:40,850 --> 00:59:44,870
So 36 is our first one here.

1200
00:59:44,870 --> 00:59:46,790
Typically, I would try
and choose something

1201
00:59:46,790 --> 00:59:50,160
about in the middle that'll
probably yield the best results.

1202
00:59:50,160 --> 00:59:56,200
So now we know that everything on
this side needs to be less than 36.

1203
00:59:56,200 --> 00:59:59,520
But also, what you could see is
that we have two spots over here.

1204
00:59:59,520 --> 01:00:04,350
So if we know that we need two
numbers that are less than the root,

1205
01:00:04,350 --> 01:00:08,670
then you could just order these
and choose the third number.

1206
01:00:08,670 --> 01:00:09,390
OK.

1207
01:00:09,390 --> 01:00:11,550
>> So why don't we start with this side?

1208
01:00:11,550 --> 01:00:17,270
So if we know that everything on
this side needs to be less than 36--

1209
01:00:17,270 --> 01:00:21,290
but if we look at this one,
we know that this number

1210
01:00:21,290 --> 01:00:25,180
has to be less than this number, right?

1211
01:00:25,180 --> 01:00:30,810
Because this number here
is on the right side.

1212
01:00:30,810 --> 01:00:34,680
And remember, just as in our larger
tree, everything on the right

1213
01:00:34,680 --> 01:00:37,130
needs to be larger than the root.

1214
01:00:37,130 --> 01:00:40,540
In this way, we know that
whatever is in this needs

1215
01:00:40,540 --> 01:00:43,090
to be larger than whatever's here.

1216
01:00:43,090 --> 01:00:44,020
OK?

1217
01:00:44,020 --> 01:00:46,340
>> So we have two choices
for these two bubbles.

1218
01:00:46,340 --> 01:00:49,830
We have 32 and 34-- or sorry.

1219
01:00:49,830 --> 01:00:53,330
20 and 34.

1220
01:00:53,330 --> 01:00:56,500
So how do you think
we might put these in?

1221
01:00:56,500 --> 01:00:59,230
If this one has to be
bigger than this one,

1222
01:00:59,230 --> 01:01:04,340
that means we want to
have 20 here and 34 here.

1223
01:01:04,340 --> 01:01:05,340
OK.

1224
01:01:05,340 --> 01:01:09,380
>> So in the same way, we look
at this kind of sub tree.

1225
01:01:09,380 --> 01:01:14,994
And we say, OK, we have not 36.

1226
01:01:14,994 --> 01:01:20,460
We have 106, 52, and 59.

1227
01:01:20,460 --> 01:01:21,590
Right?

1228
01:01:21,590 --> 01:01:24,820
In this case here, we
know that this one needs

1229
01:01:24,820 --> 01:01:29,570
to have one thing that's greater than
it and one thing that is less than it.

1230
01:01:29,570 --> 01:01:30,100
Right?

1231
01:01:30,100 --> 01:01:34,580
So if we put these in order, it's just
about finding that middle value again.

1232
01:01:34,580 --> 01:01:35,766
So our middle value is 59.

1233
01:01:35,766 --> 01:01:38,524

1234
01:01:38,524 --> 01:01:40,190
So then we say, OK, what's less than 59?

1235
01:01:40,190 --> 01:01:41,826
Well, that's 52.

1236
01:01:41,826 --> 01:01:42,950
And what's greater than 59?

1237
01:01:42,950 --> 01:01:45,120
Well, that's 106.

1238
01:01:45,120 --> 01:01:45,930
OK?

1239
01:01:45,930 --> 01:01:49,430
So it's just a bit like a puzzle.

1240
01:01:49,430 --> 01:01:53,160
It typically helps, especially
in small trees like this,

1241
01:01:53,160 --> 01:01:56,617
if you just order it, if you
know how many are on the left

1242
01:01:56,617 --> 01:01:58,450
and how many are on the
right, that can just

1243
01:01:58,450 --> 01:02:01,050
allow you to choose what
should be at your root.

1244
01:02:01,050 --> 01:02:02,922
And then you can kind
of work from there.

1245
01:02:02,922 --> 01:02:05,080
Mm-hm.

1246
01:02:05,080 --> 01:02:05,580
33?

1247
01:02:05,580 --> 01:02:07,570
Sure.

1248
01:02:07,570 --> 01:02:10,120
OK.

1249
01:02:10,120 --> 01:02:17,410
So we want to create a node
or a binary search tree.

1250
01:02:17,410 --> 01:02:20,416
And let's look at what might be in it.

1251
01:02:20,416 --> 01:02:26,130

1252
01:02:26,130 --> 01:02:28,600
And I think this will
actually be our last problem.

1253
01:02:28,600 --> 01:02:29,510
Ah.

1254
01:02:29,510 --> 01:02:30,010
OK.

1255
01:02:30,010 --> 01:02:48,190

1256
01:02:48,190 --> 01:02:48,690
OK.

1257
01:02:48,690 --> 01:02:55,580

1258
01:02:55,580 --> 01:02:58,040
>> This is like what we can
think of as a node, right?

1259
01:02:58,040 --> 01:03:01,610
We have some value, and we
know that it will either

1260
01:03:01,610 --> 01:03:03,830
have left and right children.

1261
01:03:03,830 --> 01:03:08,420
Binary search tree-- that means
that it has, at most, two children.

1262
01:03:08,420 --> 01:03:08,920
OK?

1263
01:03:08,920 --> 01:03:12,690

1264
01:03:12,690 --> 01:03:15,540
Let's think about the way we
defined a linked list, right?

1265
01:03:15,540 --> 01:03:17,740
>> We had some int that
represented the value.

1266
01:03:17,740 --> 01:03:20,760
We had some pointer that represented
what it was going to next.

1267
01:03:20,760 --> 01:03:23,350
Binary search tree is very similar.

1268
01:03:23,350 --> 01:03:27,980
We still have some value,
n, that we give it, right?

1269
01:03:27,980 --> 01:03:31,750
And then I drew these very
explicitly with arrows,

1270
01:03:31,750 --> 01:03:34,010
because they are effectively pointers.

1271
01:03:34,010 --> 01:03:34,940
OK?

1272
01:03:34,940 --> 01:03:38,500
>> So n is typically what?

1273
01:03:38,500 --> 01:03:39,230
It's some value.

1274
01:03:39,230 --> 01:03:41,800
What do we typically designate it as?

1275
01:03:41,800 --> 01:03:42,500
An int.

1276
01:03:42,500 --> 01:03:49,980
So we have some int n, or int value,
or whatever you'd like to call it.

1277
01:03:49,980 --> 01:03:53,230
And then we have the left
child and the right child.

1278
01:03:53,230 --> 01:03:54,570
Right?

1279
01:03:54,570 --> 01:03:58,060
And we know that what they're
point-- what are they pointing to?

1280
01:03:58,060 --> 01:04:01,560
They're pointing to other nodes, right?

1281
01:04:01,560 --> 01:04:07,540
So how would we declare a node pointer?

1282
01:04:07,540 --> 01:04:10,480

1283
01:04:10,480 --> 01:04:11,460
>> AUDIENCE: [INAUDIBLE].

1284
01:04:11,460 --> 01:04:12,472
>> SPEAKER 1: Mm-hm.

1285
01:04:12,472 --> 01:04:14,305
And we're going to have
two of those, right?

1286
01:04:14,305 --> 01:04:18,070

1287
01:04:18,070 --> 01:04:26,710
And then we can literally
do left for the left child

1288
01:04:26,710 --> 01:04:30,950
and right for the right child.

1289
01:04:30,950 --> 01:04:31,820
Actually-- sorry.

1290
01:04:31,820 --> 01:04:33,155
Because we need struct.

1291
01:04:33,155 --> 01:04:36,250

1292
01:04:36,250 --> 01:04:41,580
>> So struct is because we haven't
finished declaring a node yet.

1293
01:04:41,580 --> 01:04:47,070
So node is within here.

1294
01:04:47,070 --> 01:04:49,640
It's kind of like a
recursive definition, right?

1295
01:04:49,640 --> 01:04:53,140
So when we are within
this definition, we

1296
01:04:53,140 --> 01:04:57,310
haven't finished declaring
node as the structure,

1297
01:04:57,310 --> 01:04:59,380
so we have to do struct
node just to say, yes,

1298
01:04:59,380 --> 01:05:03,930
we are in fact referring
back to ourself type thing.

1299
01:05:03,930 --> 01:05:07,410
That like once it's
created, it'll be fine.

1300
01:05:07,410 --> 01:05:10,890
>> So how big do you guys think this is?

1301
01:05:10,890 --> 01:05:13,650
What's the size of this structure?

1302
01:05:13,650 --> 01:05:14,370
12.

1303
01:05:14,370 --> 01:05:14,870
Why?

1304
01:05:14,870 --> 01:05:18,990

1305
01:05:18,990 --> 01:05:19,664
Precisely.

1306
01:05:19,664 --> 01:05:21,830
And in fact, one of the
first questions one Quiz One

1307
01:05:21,830 --> 01:05:24,170
is about sizes, which is why I asked.

1308
01:05:24,170 --> 01:05:25,230
All right.

1309
01:05:25,230 --> 01:05:29,350
>> We are going to end, because the
DCE will yell at me if we don't.

1310
01:05:29,350 --> 01:05:33,790
But if you guys have any questions,
of course, email me, let me know.

1311
01:05:33,790 --> 01:05:35,190
You guys are going to rock it.

1312
01:05:35,190 --> 01:05:37,210
I'm super excited.

1313
01:05:37,210 --> 01:05:39,380
You guys will be done as
of Wednesday, and then

1314
01:05:39,380 --> 01:05:43,150
you'll get to work on your final
projects, and it's going to be awesome.

1315
01:05:43,150 --> 01:05:48,784
>> I will be here next
week from 4:00 to 4:30

1316
01:05:48,784 --> 01:05:50,700
if you guys want to come
pick up your quizzes.

1317
01:05:50,700 --> 01:05:54,410
If you want to find me some other time
or just coordinate a different time,

1318
01:05:54,410 --> 01:05:56,460
feel free to let me know.

1319
01:05:56,460 --> 01:05:58,670
Otherwise, this is our last section.

1320
01:05:58,670 --> 01:06:01,070
So it was great to see you guys.

1321
01:06:01,070 --> 01:06:02,450
Please take more candy.

1322
01:06:02,450 --> 01:06:05,390
And good luck on your quiz.

1323
01:06:05,390 --> 01:06:06,687