WEBVTT

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This presentation is delivered by the
Stanford Center for Professional Development

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Hi! Welcome, welcome to CS106B,
Programming Abstractions.

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(maybe now our mic is on? Oh, that's iteresting.)

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The website was probably the most important
thing to take away from here,

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where can you find information about the class

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for the talk today and give some
overview and stuff like that,

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but this is the home base for all the material.

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If you managed to get the handouts
on the way in, you're golden.

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Otherwise, you can grab them from the website.

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There's a lot of background information,
staff information,

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office hours, all sorts of stuff gathered there.

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It's kind of one stop shopping for

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figuring things out about our course.

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Let me tell you what I'm going to do today.

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The first day of, I know a lot of you are shopping

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trying to figure out what's the right fit for you,

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so hopefully today, I'm going to
try to give you some information that will

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help you make a good decision.

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I want to tell you a little bit
of what our course is about,

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tell you a little bit about the
administration and logistics

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most of that stuff is pretty ordinary,
and you can read about it.

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Of course, I have to do a little bit of marketing.

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I get to give you my unbiased opinions

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of why this is the absolute
best class you could possibly take.

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(I get paid per student, you know.)

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(That's not true.)

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Maybe we'll even have time to check out

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a little bit of the C++ language
before we're done and set today.

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(and this needs to go away)

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Let me tell you about CS106.

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CS106 is the introductory programming
sequence here at Stanford.

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It's our version of CS1,
where you start at the beginning

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when you are interested in
learning more about programming.

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We have a two-quarter sequence,
A and B, that kind of follow together.

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They're not particularly tightly coupled, which is to say

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if you took A and you took little a break, you could come back to B.

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Or maybe you you actually took a variant of 106a type course

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that is similar at another institution,
you're probably in a fine place for starting mid stream.

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We also have an alternate form of B, the CS106X, which is kind of an honors version of that second course.

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So after you've taken that first course and you're feeling really jazzed up,

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there is an alternative more intense way to get through the second course that's

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offered. It's offered this quarter, in fact, so if you're

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thinking actually about that, that is an option for you as well as

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sticking with us.

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What do we do in 106A?

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'A's official title is programming methodology.

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It is starting at the very beginning

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and assuming you have no background in programming.

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It's teaching you how it works,

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what the languages look like, what the syntax is like, what things you need

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to know about how to solve problems using a computer.

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It covers a lot of the fundamentals about logic control

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and in general, I think the big issues of 106A

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have less to do with any particular syntax or

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feature that you learn about a language but

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about how do you solve problems on a computer?

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Somebody gives you a specification of

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you need to write a program that does X,

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and you have to figure out how to make that happen,

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how to break it down,

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how to step through it, how to develop it, how to test it,

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how to iterate on it, how to make changes in it later,

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how to debug it when it's not working well,

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and those things, (I think), transcend any particular language.

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We happen to use the Java programming language in our 106A course

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because it's a great tool for introductory programming,

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but I don't think of that as being really critical.

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In fact, if your introductory course was in some other language,

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some other fairly modern, high level language

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- let's say

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you've learned in Python, C, Scheme, or something other than Java,

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you're probably still fine, 'cause what we're really counting on in B is that you know how to

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program and think like a computer scientist

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know how to solve problems

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Not a lot of the details of the syntax

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are going to be important to us.

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"B" picks up from there, saying okay, you've got some fundamentals.

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Let's start really learning some of the techniques that extend the range of

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problems you can solve.

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We look at recursion, which is one of the fundamental

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problem solving techniques that involves using

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something akin to mathematical induction

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to solve problems in terms of themselves.

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Looking at a lot of algorithms for sorting

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and searching and hashing and doing

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things efficiently, knowing how to compare

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and contrast alternatives in algorithms,

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having some formalisms by which to discuss those things,

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and learn some of the classics that are out there for solving these problems.

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The dynamic data structure, which involves use of pointers to construct things

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like lists, trees and heaps, graphs that

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model certain structures that are very effective in solving certain kinds of

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problems - we'll work through those.

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A large part of our time is spent on this concept

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of data abstraction, which is why

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abstraction shows up as the main word in our title.

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As we start to solve more and more complex problems,

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the code itself can kind of become overwhelming if we don't have some

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technique for managing that complexity.

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One of the big themes for 106B is how we can use this idea of abstraction,

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building something and dealing with the low level details but then

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closing up the box and now treating it as a

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a fixed entity and building on top of that

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and then closing another layer around that

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as a way of working on something, finishing it

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moving on to some larger piece without

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having those details clouding our way.

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It's a very powerful technique for solving larger problems.

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In that context,

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we'll be looking at some of the classic data structures,

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like stacks, queues, lists, maps and sets

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as part of the domain for that.

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We do happen to use the C++ programming language,

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but this is not a C++ course, so to be clear about what you're

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getting versus what you wanted,

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we use Java here (as a vehicle) [a].

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We use C++ here (as a vehicle) [b].

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We happen to think there are good reasons

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to actually expose you to both languages.

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(ill talk about that more later)

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In particular, C++ is an enormous language.

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It has a lot of language features as well as

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a very very large standard library,

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and our goal is not at all

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to turn you into this industrial strength

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knows every detail about quirks

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and ins and outs of C++.

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There is another class, 193D, that

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does attempt to do that.

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In fact, if that's what you're looking for,

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I suggest you take a look at that.

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What we're here about is learning

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advanced programming techniques

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taking those foundations and building on them

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to be able to solve more interesting problems.

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We happen to use C++.

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You will learn some C++, but I almost

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consider it a side effect

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of what we're doing.

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Just a little note on placement

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if you're kind of in between and not really sure,

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these are the very very rough guidelines, but they give you

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some idea of which groups gravitate where.

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If you are new to programming or

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you're not confident about your background

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- maybe it was a long time ago, if it was self-taught.

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Maybe it was in a course that you

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felt was not as good as it could have been

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or you didn't do as well in it,

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106A is a great place to start.

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It actually is by all accounts

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an extremely popular course at Stanford

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and services a wide group of people

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with a little bit of background or no background.

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All very well getting them up to speed.

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If you do have something like a solid first course experience

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So you did well in 106A or took a similar course

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or perhaps even self-taught your way

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through a lot of those materials and you feel ready to move on, 106B.

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An AP course in high school -

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the A curriculum is a pretty good match for 106A here

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so you're in a great place.

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If you have this and you've got a little bit more going for you

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or you're super enthused and you have a

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lot of extra time this quarter

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and want to sit in the company of only

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the uber geeks,

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you can check out 106X,

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Which is a varient of B

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which covers the same kind of topical ground

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but at a different level intensity.

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It amps up a little bit of the assignments,

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covers some of the material that we won't get a chance to cover,

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and

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just pushes the envelope a little bit there.

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If you have experience comparable to the first two courses

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- you've

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done all the things that we're talking about here in B

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and you feel comfortable with it,

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it might be that the right place for you is 107,

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which is the third course in our sequence.

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And just skipping over our 106 courses entirely

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That's somewhat rare,

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so if you're thinking about that, I encourage you to

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talk to me a little bit to make sure

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that you won't be missing out on something important

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in doing so, but certainly there are students who have

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for example, the AP CS A-B curriculum

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is pretty comparable to this course here,

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and so depending on how high quality the course you had was,

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it might very well be that 107 is right.

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In some situations where that course was a little bit lacking,

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there may be some ways that we can help reinforce

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the things you've learned and build a stronger foundation

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to move forward from rather than jumping ahead.

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Any questions about placement?

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That sort of thing.

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(Am I talking too fast?)

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(good, I like that, you can sit in the front whenever you want)

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Lets talk philosophy

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I think there's a statement about what we officially are,

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but I also think that 106 has a long tradition at Stanford

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that comes back from student motivation.

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I was here as an undergrad in the 80s

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when 106s were just getting off the ground,

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and at the time, Stanford only had a graduate

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computer science department, and

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the belief in the nsaid period for computer science

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was you should get a math degree,

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and only then would you be mature enough

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to learn about computers.

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You weren't ready as a freshman.

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was a groundswell of Stanford students

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were like said 'We want access to programming. We want it.'

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That made it happen.

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and so part of the 106 was a really careful thought about what the 106's

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would be a Stanford and what we want them to be

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in a philosophical sense.

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One is that we welcome students of
all majors and backgrounds.

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We don't have a version of 106 that's for the majors or

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potential majors and a version that's for the non-majors

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and a version that's terminal (you just want to get out of here).

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We really think that we can bring you all together

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and design a course that addresses this wide

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disparate group but still service that well.

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Partly because you don't know that
you are a CS major yet.

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I'm going to turn you into a CS major.
That's my plan.

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At Stanford right,
not having to make that choice about a major

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until into junior year is a gift

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to allow you to explore
and to feel unencumbered by having made some

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decision when you applied,
and I think it's important to respect that

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gift that Stanford gave you by
trying to make sure our courses don't

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funnel you one way or
the other before you figure it out.

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You are all welcome here.

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We try to make it accessible to everyone.

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We have certain plans 
that help to make that work.

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We do try to provide a solid,
practical foundation in programming

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that given our placement at Stanford
in the middle of the Silicon Valley,

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there's kind of a strong influence
for us to try to produce students

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who from the get go are

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learning things that are actually quite useful

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outside of the classroom

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rather than teach you a very academic

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interesting and mathematical
language like Scheme

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that is very

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rarely used outside of the classroom.

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We're trying to teach you on the tools,

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languages and techniques that are actually in active practice.

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We are using Java and C++,
two of the most prevalent languages

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out in the industry, and
we do a lot of learn by doing.

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We assign challenging, full-fledged
programs that you work on and you build

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and so it's not designed to be
academic exercises.

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You really are building skills
that have applicability here and
outside of the class.

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We have a big emphasis on

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truth and beauty.

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This is one area in which some of the
substitute courses

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that we have seen students come in with
have a little bit more trouble with

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is tackling this part of it,
which is that there are

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a lot of ways you can get a program to work.

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Many of them are not pretty.

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You can just type and type and type and
(Monkies shakespeare, whatnot)

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eventually, you can get your way to
something that works.

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Well +1, -1, what if I move it here
what if I copy and paste this there

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what if I change that name?

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That, in the end,
might produce a program that from

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external appearances works.

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It plays hangman, or whatever was the
desired goal, but that internally is a mess.

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It's not well structured.
It's not well commented.

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It's not easy to understand.
It wouldn't be easy to modify.

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It makes a lot of decision that are really sub optimal,

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and we're really interested in producing
engineers

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that have a good sense of design and 
really appreciate what is involved in writing

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good, well designed software, 
not just working software.

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We will be giving you feedback on

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both the correctness and
functionality of your code

00:12:01.740 --> 00:12:05.000
as important if not more so,

00:12:05.000 --> 00:12:08.000
also on how well we think you did
at designing and implementing and

00:12:08.000 --> 00:12:11.030
writing code that is of
a high quality.

00:12:11.030 --> 00:12:12.030
We make a big deal out of that.

00:12:12.030 --> 00:12:14.000
That is something that is not
always shared by other classes,

00:12:14.000 --> 00:12:16.510
and so in particular, someone who is self-taught

00:12:16.510 --> 00:12:20.000
or in a class that didn't emphasize this
might feel that there's a little bit of a gap there


00:12:20.000 --> 00:12:21.000
we need to make
that up with you,

00:12:21.000 --> 00:12:23.490
and we can work with you.

00:12:23.490 --> 00:12:26.000
This is a very individual thing,
because there's not one good example of

00:12:26.000 --> 00:12:28.000
the perfect style

00:12:28.000 --> 00:12:31.000
in the way that a lot of different people

00:12:31.000 --> 00:12:34.000
express themselves in written communication

00:12:34.000 --> 00:12:34.990
very well but differently.

00:12:34.990 --> 00:12:36.500
The same thing is true about programs.

00:12:36.500 --> 00:12:40.000
You will have your own unique style,
and we'll work with you to coach you on getting your

00:12:40.000 --> 00:12:44.010
style to come through and
be beautiful and elegant.

NOTE Paragraph

00:12:46.000 --> 00:12:50.000
This kind of comes back to point 1
we make heavy use of undergraduate

00:12:50.000 --> 00:12:53.000
section leaders as mentors in this program.

00:12:53.000 --> 00:12:59.000
We have a staff of 50 or so, undergraduates
who work with the 106A, B and X courses as a team.

00:12:59.000 --> 00:13:02.000
They have specific responsibilities with their section,

00:13:02.000 --> 00:13:06.000
so mentoring and grading and meeting with

00:13:06.000 --> 00:13:09.000
sectionees to give individualized
feedback on their programs

00:13:09.000 --> 00:13:10.000
as well as

00:13:10.000 --> 00:13:13.760
answering questions, solving problems,
being in the lair 30 plus hours.

00:13:13.760 --> 00:13:16.000
They're most weekday nights about six hours

00:13:16.000 --> 00:13:17.000
and often

00:13:17.000 --> 00:13:20.000
well past the midnight when it's supposed to cut off
solving people's problems,

00:13:20.000 --> 00:13:23.000
helping when you get stuck,
answering your questions

00:13:23.000 --> 00:13:26.000
and making sure you're all
making forward progress.

00:13:26.000 --> 00:13:29.000
That comes back to point 1.

00:13:29.000 --> 00:13:31.000
In some universities where they're
choosing to use their intro course as a weeder,

00:13:31.000 --> 00:13:33.690
it's like let's separate the wheat
from the chaff early

00:13:33.690 --> 00:13:35.000
and let's make it really hard and not

00:13:35.000 --> 00:13:38.000
provide too much support,
and that way we'll make sure we get the people we want.

00:13:38.000 --> 00:13:41.000
We have a different idea.

00:13:41.000 --> 00:13:42.000
Programming is hard,
especially when you're learning.

00:13:42.000 --> 00:13:46.000
There's a lot of complexity to master,
and there are a lot of details that can

00:13:46.000 --> 00:13:49.000
interfere with moving forward,
and we don't want you

00:13:49.000 --> 00:13:52.000
to get stuck on something that
we can very easily resolve for you.

00:13:52.000 --> 00:13:55.980
So make sure you have accessible
staff members in person, in email

00:13:56.000 --> 00:13:58.000
and regularly in section

00:13:58.000 --> 00:14:04.000
to help get through the roadblocks
and keep you moving forward.

00:14:04.000 --> 00:14:08.000
What do you need to know to be
sure you're going to do well?

00:14:08.000 --> 00:14:12.000
There are people who think to
be a good computer programmer,

00:14:12.000 --> 00:14:16.000
you need to be good at math,
logic, and drinking Jolt.

00:14:16.000 --> 00:14:22.010
I think it it comes down to
personality traits than any

00:14:22.020 --> 00:14:24.500
particular technique or skill.

00:14:24.500 --> 00:14:26.000
You don't need to be good at math.

00:14:26.000 --> 00:14:29.000
How much calculus and trig shows up in this?

00:14:29.000 --> 00:14:32.000
Not very much.
A little bit of logic - that helps.

00:14:32.000 --> 00:14:36.990
I think it comes down to traits like
curiosity and determination and hard work.

00:14:37.000 --> 00:14:37.980
Starting early,

00:14:37.980 --> 00:14:41.000
asking questions
when you don't understand something,

00:14:41.000 --> 00:14:43.510
trying to solve the problem by logic
I think is very valuable

00:14:43.510 --> 00:14:45.000
Knowing how to think,
how to make steps

00:14:45.000 --> 00:14:47.960
why this case works and
why that case doesn't work

00:14:47.970 --> 00:14:51.720
thinking about that logically

00:14:51.755 --> 00:14:55.735
(well its like the movie theater now you guys will all go to sleep)
(oh look they came back) [lights]

00:14:57.000 --> 00:15:01.120
I think these are the skills
that serve you the best in this class

00:15:01.120 --> 00:15:04.010
And probably
every other thing you'd want to tackle.

00:15:04.010 --> 00:15:08.000
There is a lot of time that will be spent
to master this.

00:15:08.000 --> 00:15:11.110
I can talk about programming all I want,
(bla, bla, bla)

00:15:11.110 --> 00:15:13.000
and you can go oh, yeah, that makes a
lot of sense.

00:15:13.000 --> 00:15:16.000
But when you go to write it yourself,
it's a very different experience.

00:15:16.000 --> 00:15:19.960
That's where being
focused and staying on task

00:15:20.000 --> 00:15:25.040
and getting help when you get stuck
can help you move through that

00:15:25.080 --> 00:15:28.080
(Any questions about 106?)
(What we do,)

00:15:28.090 --> 00:15:32.070
(Why we do what we do.)
(You guys have nothing to say)

00:15:32.070 --> 00:15:34.070
(your afraid of having your)
(voice recorded aren't you?)

00:15:34.070 --> 00:15:39.020
(For all time your parents will come and see)
(that you come to class you can prove it)

00:15:40.010 --> 00:15:44.000
My unbiased opinion about why 106B is
one of the best courses at Stanford

00:15:44.000 --> 00:15:47.000
(of course I am not at all unbiased)

00:15:47.000 --> 00:15:50.000
it's going to be

00:15:50.000 --> 00:15:53.000
totally obvious when I say these things,
and you guys are going to have to go

00:15:53.000 --> 00:15:54.960
along with it.
I'm actually a

00:15:55.000 --> 00:15:58.000
geek, really big time,
and I happen to love programming.

00:15:58.000 --> 00:16:00.000
That's why I'm a perfect fit for teaching this class.

00:16:00.000 --> 00:16:01.490
I have taught 106 B or X more than I've taught

00:16:01.490 --> 00:16:04.000
any other class that I've taught at
Stanford in my time here,

00:16:04.000 --> 00:16:06.330
and that's because each quarter
when we're setting the schedule,

00:16:06.330 --> 00:16:08.000
I say give me B.
Give me X.

00:16:08.000 --> 00:16:09.000
Because there's no better course to teach.

00:16:09.000 --> 00:16:12.000
Programming is just awesome.

00:16:12.000 --> 00:16:15.000
If you love programming,
I think there's almost nothing better to do in the world.

00:16:15.000 --> 00:16:17.510
You have this task.
You're trying to get there.

00:16:17.510 --> 00:16:19.170
You're coding.
You're making stuff happen.

00:16:19.170 --> 00:16:21.940
You're testing, iterating you're running.
You see stuff.

00:16:21.950 --> 00:16:25.020
You build things.
When you're done, you know it works.

00:16:25.020 --> 00:16:28.000
That feeling when you write a paper and go
"was it good enough?"

00:16:28.000 --> 00:16:30.000
"well I dont know"
you could probably go bolster up this argument

00:16:30.000 --> 00:16:32.280
When a program works,
you know it.

00:16:32.290 --> 00:16:36.000
It does what it's supposed to do.
It gets the right answer.

00:16:36.000 --> 00:16:38.020
It plays the game.
It solves the problem.

00:16:38.020 --> 00:16:42.000
Finding and fixing that last bug
- although debugging is one of the last

00:16:42.000 --> 00:16:45.000
aspects of programming a lot of people bemoan about;
I happen to think that if you

00:16:45.000 --> 00:16:49.000
are driven by debugging,
that is one of the most awesome detective stories

00:16:49.000 --> 00:16:53.980
Trying to figure out why it happened when you did this,
when you moved that why it went this way

00:16:54.000 --> 00:16:57.000
and what this effect caused
and understanding once you make the fix how it fixes it

00:16:57.000 --> 00:16:58.930
staying up late.

00:16:58.930 --> 00:17:02.000
I have stayed up late more nights debugging
than anything else in my life,

00:17:02.000 --> 00:17:04.000
and I'm not sad about that at all.

00:17:04.000 --> 00:17:08.000
That means I'm in the right place.
Hopefully, some of that resonates with you.

00:17:09.020 --> 00:17:12.000
If that sounds really awful to you,

00:17:12.000 --> 00:17:14.000
hopefully we can change your mind a bit.

00:17:14.000 --> 00:17:18.000
That is, in some ways,
part of what drives computer science is this

00:17:18.000 --> 00:17:21.000
wanting to build things.
We are engineers.

00:17:21.000 --> 00:17:24.000
We have this computer science name.
Just remember

00:17:24.000 --> 00:17:29.000
- any subject
that's name is something science is not a science.

00:17:29.000 --> 00:17:31.950
We're trying to puff ourselves up a bit.

00:17:32.000 --> 00:17:34.000
We do a lot of really great work,

00:17:34.000 --> 00:17:37.000
and there are a lot of neat scientific
principles and theories that

00:17:37.000 --> 00:17:38.000
underpin what we do,

00:17:38.000 --> 00:17:41.000
but in the end,
I think what drives a lot of us is just

00:17:41.000 --> 00:17:44.990
the engineering
- building stuff that is really neat.

00:17:45.010 --> 00:17:49.000
It kind of reminds me that my
husband's a mechanical engineer, and so I

00:17:49.000 --> 00:17:52.220
used to be envious, because
he would always build things.

00:17:52.220 --> 00:17:57.000
M.E.'s always toting foam core around the campus
on their paper bicycles and stuff, and it's like

00:17:57.000 --> 00:18:00.000
they build all these things.
Now, having watched all the things he builds, it's like

00:18:00.000 --> 00:18:02.000
mechan-e is really hard.
You need all these materials.

00:18:02.000 --> 00:18:05.320
You need all these tools.
You need this mill, you need this lathe

00:18:05.320 --> 00:18:07.430
You need the hotmelt glue gun,
which burns the heck out of your fingers

00:18:07.430 --> 00:18:08.160
anytime you touch it.

00:18:08.160 --> 00:18:10.660
To build anything.

00:18:10.930 --> 00:18:12.560
In computer science, you don't need anything.

00:18:12.560 --> 00:18:14.000
You need a compiler and you need a computer.

00:18:14.000 --> 00:18:15.030
You need your thought.

00:18:15.030 --> 00:18:18.000
It's like an abstraction we built out of our brains.

00:18:18.000 --> 00:18:20.000
There's this relatively small set of things
that you need to master

00:18:20.000 --> 00:18:23.990
and then you can combine them in these very
sophisticated and interesting ways to solve all sorts of problems.

00:18:24.000 --> 00:18:26.000
There's a very low overhead,

00:18:26.000 --> 00:18:30.000
and the range of things you can attack
with the same set of skills is huge.

00:18:30.000 --> 00:18:36.020
Every domain out there can benefit from somebody
applying computers in a useful way without fail.

00:18:36.020 --> 00:18:39.080
There's all sorts of problems
where technology is part of the answer

00:18:39.080 --> 00:18:41.000
not the only answer,
but certainly something that you can take

00:18:41.000 --> 00:18:44.000
whatever interest you have
and combine it with computer science

00:18:44.000 --> 00:18:47.000
and construct something cool.

00:18:47.000 --> 00:18:51.000
I happen to think that what
happens in the second course is amazing.

00:18:51.000 --> 00:18:54.000
The first course,
you've kind of got to get up to speed,

00:18:54.000 --> 00:18:57.000
and there's a lot of basic material
that needs to get covered,

00:18:57.000 --> 00:19:00.000
and it does set you on the right path,
but in this course, we really

00:19:00.000 --> 00:19:04.000
get to blossom beyond the basic things.

00:19:04.000 --> 00:19:07.000
There are a bunch of really neat
and very accessible techniques

00:19:07.000 --> 00:19:11.000
that a second quarter student can understand
and master and do really cool things with.

00:19:11.000 --> 00:19:14.050
You can learn how to do something like
create a database

00:19:14.050 --> 00:19:17.000
that has a million entries

00:19:17.000 --> 00:19:20.900
and then ask for somebody by name and be able to
instantaneously be able to find that name.

00:19:20.900 --> 00:19:23.000
Not by looking through a million
entries trying to find that name

00:19:23.000 --> 00:19:26.000
Change the size of it.
Make it ten million, a billion, and still be able to

00:19:26.000 --> 00:19:29.000
provide that kind of instantaneous access.
You're going to learn how to do that.

00:19:29.000 --> 00:19:32.000
The technique is not some superhuman thing.

00:19:32.000 --> 00:19:34.000
It's something very clever, admittedly,

00:19:34.000 --> 00:19:36.000
but it's very accessible.

00:19:36.000 --> 00:19:40.000
Taking that same million thing and
learning how to sort it efficiently.

00:19:40.000 --> 00:19:42.000
What if you happen to know things about how it's
almost sorted but just a little but out of sorts?

00:19:42.000 --> 00:19:47.000
Are there ways you can actually make it
even faster to put it in sorted order?

00:19:47.000 --> 00:19:50.000
There are techniques, for example,
like recursion that take on problems that

00:19:50.000 --> 00:19:53.000
you might not have any idea when you
first look at the problem how to solve

00:19:53.000 --> 00:19:57.450
but once you've got your head around recursion,
you can look at that and say

00:19:57.450 --> 00:20:01.030
"I can write a five line function
that will solve that problem."

00:20:01.030 --> 00:20:05.669
This is the kind of power we're going to
give you with our quarter together.

00:20:05.669 --> 00:20:10.000
There's a bunch of really amazing
theoretical and algorithmic stuff to explore.

00:20:10.000 --> 00:20:14.000
That really increases the kind of things
you can do with programming.

00:20:14.000 --> 00:20:17.840
I'm particularly fond of it.

00:20:18.010 --> 00:20:20.010

As always, I think

00:20:20.010 --> 00:20:23.000
the section leading program that we have
created and built at Stanford

00:20:23.000 --> 00:20:27.030
Is a huge part of what makes our 106
courses so successful,

00:20:27.030 --> 00:20:28.000
and so

00:20:28.000 --> 00:20:32.990
having somebody who's individually
working with you, meeting with you weekly

00:20:34.000 --> 00:20:37.000
and giving you that feedback that's
individualized and personalized for you

00:20:37.000 --> 00:20:41.000
and helping you get through the rough spots
is a lot of what helps to make the experience

00:20:41.000 --> 00:20:44.000
very fun and very personal, too.

00:20:44.000 --> 00:20:48.910
What section leaders do I have here?
Any? Not a one.

00:20:49.000 --> 00:20:52.000
Those fabulous section leaders.
Where are they again? section leaders?

00:20:52.000 --> 00:20:54.030
Did i say they were fabulous?
I meant. <i>laughs</i> Uhh no.

00:20:54.030 --> 00:20:57.000
We haven't yet identified who's going
to what class, so maybe they're all

00:20:57.000 --> 00:21:00.851
thinking they're going to go somewhere else,
but they're wrong. We'll get some.

00:21:03.940 --> 00:21:05.000
106B - great. You agree?

00:21:05.000 --> 00:21:07.000
Have I convinced you?

00:21:07.000 --> 00:21:10.000
Is anybody still hesitant?

00:21:13.000 --> 00:21:16.000
Is it a lot of work?
Oh, no. <i>laughs</i>

00:21:16.000 --> 00:21:19.000
I just exude it. Osmosis. you learn it.

00:21:21.980 --> 00:21:24.920
Let me tell you a little bit about logistics.

00:21:26.000 --> 00:21:30.000
There are some random things you may want
to know about how the class works.

00:21:30.000 --> 00:21:34.000
That the first day I am supposed to do.


00:21:34.000 --> 00:21:38.360
We're going to meet here
Monday, Wednesday, Friday 2:15 to 3:05.

00:21:38.360 --> 00:21:41.920
In glorious download
[ FIXME ] audiotorium

00:21:41.930 --> 00:21:45.060
It looks like we almost
exactly fit in our classroom,

00:21:45.060 --> 00:21:47.790
which means we're all
going to be very friendly and cozy.

00:21:47.790 --> 00:21:51.131
The lectures are being taped
and are available online,

00:21:51.131 --> 00:21:56.540
and so that has the neat side effect that
you can watch them and review them later.


00:21:56.540 --> 00:21:58.000
You could watch them lots of times.

00:21:58.000 --> 00:22:01.000
It also means that if it were pouring rain and
you were sitting at home in your bunny slippers,

00:22:01.000 --> 00:22:04.000
you could just say hey,
I'm not going outside and you could

00:22:04.000 --> 00:22:06.000
turn on your computer and watch.

00:22:06.000 --> 00:22:09.000
I'm a big fan of having you come in person.
That's because I don't want to

00:22:09.000 --> 00:22:11.000
lecture to an empty room.

00:22:11.000 --> 00:22:14.000
I also think there's an interaction there

00:22:14.190 --> 00:22:19.000
that I'm fond of, and so I hope that you
will make every effort to attend in person
as much as you can.

00:22:22.010 --> 00:22:26.990
It is nice to know that if you do miss a lecture or you

00:22:27.000 --> 00:22:29.940
get caught up with something, you'll have a chance to review it later online.

00:22:30.000 --> 00:22:32.000
We will have sections that will meet once a week,

00:22:32.000 --> 00:22:34.970
just like 106A.

00:22:35.000 --> 00:22:38.000
The section leader who meets with you is the one

00:22:38.000 --> 00:22:41.000
who will be grading your programs and sitting with you
and doing the conferences.

00:22:41.000 --> 00:22:45.940
What you need to do to get yourself
into a section - there are several section times listed.

00:22:45.960 --> 00:22:47.960
They are totally bogus. (so ignore that)

00:22:51.000 --> 00:22:53.000
What you do is you go to the online
- if you go to our class webpage, there's a link that tells

00:22:53.000 --> 00:22:56.000
you how to sign up for a section.
The section times aren't up right now, but they will go up tomorrow,

00:22:56.000 --> 00:22:58.000
and they'll be up through the weekend.
You go in and put in your preferences

00:22:58.000 --> 00:23:03.930
about what times fit your schedule or not,
and there's this big computer program

00:23:04.000 --> 00:23:08.790
that does this magic matching that gets
everyone into a section that fits their schedule.

00:23:08.880 --> 00:23:11.880
That will happen early next week.

00:23:14.000 --> 00:23:18.850
The signups will be up from Thursday at 5:00
until Sunday at 5:00.

00:23:18.960 --> 00:23:22.000
If by Sunday at 5:00
you've got your schedule fixed, then you're fine.

00:23:22.000 --> 00:23:25.000
If you happen to change after Sunday at 5:00 and after the assignments have been made,

00:23:25.000 --> 00:23:27.000
at that point, it's a little bit harder.

00:23:27.000 --> 00:23:28.000
We can make adjustments, but it's on a very case-by-case basis.


00:23:28.000 --> 00:23:31.000
Where we have space and where we can accomodate you.

00:23:31.000 --> 00:23:33.000
The best thing you can do

00:23:33.000 --> 00:23:36.000
is by Sunday at 5:00 have a pretty firm idea
about what you can and can't do.

00:23:36.000 --> 00:23:37.000
There's a list of preferences,
so maybe what you can do

00:23:37.000 --> 00:23:40.000
is pick things that you know will work no matter

00:23:40.000 --> 00:23:41.000
what happens.

00:23:41.000 --> 00:23:44.000
for antyhing that is variable if you just dont offer things that you know might

00:23:44.000 --> 00:23:44.840
go away

00:23:44.980 --> 00:23:49.930
so there is a list of 20 times and you say I can make these 5

00:23:49.930 --> 00:23:52.390
And that way you wont get yourselves in trouble

00:23:52.390 --> 00:23:54.910
in things that might change.

00:23:55.000 --> 00:23:59.000
The workload - everybody wants
to know how much work.


00:23:59.000 --> 00:24:02.000
It's a five-unit class, and
it's a five unit engineering class.

00:24:04.000 --> 00:24:06.000
You get your five units worth,

00:24:06.000 --> 00:24:09.990
I would say, so don't worry about that. I won't shortchange you.

00:24:11.010 --> 00:24:15.000
We have programming assignments not quite weekly.
I think there are seven of them across

00:24:15.000 --> 00:24:18.960
ten weeks, so you can calculate it out.
It's about a week and a third

00:24:19.000 --> 00:24:20.000
for any particular one.

00:24:20.000 --> 00:24:22.030
The students report

00:24:22.030 --> 00:24:25.000
that it's about a 15-20 hour project, each of them.

00:24:25.000 --> 00:24:28.000
Some people get them done in less than that.
Some people take a little bit more.

00:24:28.000 --> 00:24:33.030
I would say that's kind of the
mode range for what people are reporting.

00:24:33.030 --> 00:24:37.000
I do think that of the people who report less,
some of those are

00:24:37.000 --> 00:24:41.000
people who are naturally gifted,
but a lot of it has to do with your habits

00:24:41.000 --> 00:24:43.000
about how you work and
how you make progress, so

00:24:43.000 --> 00:24:46.000
if you are one of the people who feels 
you might be more likely to be on the other

00:24:46.000 --> 00:24:49.000
end, you can come and talk to
me and I can give you some suggestions.

00:24:49.000 --> 00:24:55.630
Choosing to work in the lair where the
helpers are on duty has really positive effects

00:24:55.630 --> 00:24:58.000
effects in that when you get stuck,
you have easy access to

00:24:58.000 --> 00:24:59.000
somebody helping you work through it

00:24:59.000 --> 00:25:02.000
rather than spending an hour or two
fighting something that turns out to be

00:25:02.000 --> 00:25:05.000
simple but required knowing something
that you didn't yet know.

00:25:05.000 --> 00:25:10.250
I'm a big fan of learning things yourself.
There's also a time when a well-placed

00:25:10.590 --> 00:25:14.000
bit of advice from somebody
can save you a lot of time.

00:25:15.000 --> 00:25:22.160
There will be a midterm and a final exam.
They'll both be in class, open book, open notes.

00:25:22.160 --> 00:25:24.010
The midterm is actually technically out of class.

00:25:24.010 --> 00:25:28.870
have it at night because we need more than
a 50-minute period to get any coverage of that.

00:25:28.870 --> 00:25:31.067
Our final exam is scheduled in
our university-scheduled slot.

00:25:31.067 --> 00:25:36.000
Sadly, that is at the very
end of the exam week,

00:25:36.000 --> 00:25:37.980
but that's when the registrar put us,
and that's when we need to go.

00:25:38.030 --> 00:25:44.010
You may want to take a look at that before
you head off to Acapulco for spring break.

00:25:44.010 --> 00:25:45.010
you need to make sure
you are here for the exam.

00:25:45.010 --> 00:25:48.980
Male audience: Is the course leader available online?

00:25:48.980 --> 00:25:53.060
Unfortunately, our publisher will not allow me to distribute the course leader electronically.

00:25:54.000 --> 00:25:57.000
They're not exactly very in the modern age on this.

00:26:00.080 --> 00:26:02.000
I'm working on it is the truth.

00:26:02.000 --> 00:26:06.040
By the time the world sees this, hopefully, we will have some other strategy.

00:26:06.040 --> 00:26:08.800
We currently are in negotiations.

00:26:08.880 --> 00:26:11.000
The nice thing about the course reader is that
we have not changed it in the last year.

00:26:11.000 --> 00:26:14.000
If you know somebody who has
it from last fall or last spring.

00:26:14.000 --> 00:26:18.000
it has some minor edits and typos that were fixed,

00:26:18.000 --> 00:26:20.000
so if you can get a hold of an old one, it's good.

00:26:20.000 --> 00:26:23.100
We are getting no royalties on it.

00:26:23.100 --> 00:26:26.950
We're publishing it at production cost, so where it

00:26:26.950 --> 00:26:31.970
would have been a $100.00 textbook
had it been bound and all snappy.

00:26:32.000 --> 00:26:36.000
you're just getting what it cost to photocopy and bind the thing, and Eric and

00:26:36.070 --> 00:26:39.980
I are eating ramen.

00:26:40.000 --> 00:26:42.000
It's hopefully cheap enough that

00:26:42.000 --> 00:26:44.000
you can find a way to get to one

00:26:44.000 --> 00:26:47.500
or get an old one without it being
too much of an obstacle.

00:26:49.000 --> 00:26:52.800
People in general find the course
reader to be an asset.

00:26:52.800 --> 00:26:54.060
We do say it's required reading.

00:26:54.060 --> 00:26:58.530
It does have a lot of material that's very
useful in understanding the course.

00:26:58.610 --> 00:27:02.000
There are other people who
don't make as big a use of it,

00:27:02.000 --> 00:27:05.000
but there are some sections that
are really very valuable

00:27:05.000 --> 00:27:08.020
and other ones that may be more
or less depending on your learning style.

00:27:08.020 --> 00:27:11.800
Whether you appreciate more of a chance to
read background material and more examples.

00:27:11.800 --> 00:27:15.000
There's also a lot of good sample problems in it

00:27:15.000 --> 00:27:18.600
and review questions in it that help to test your understanding.

00:27:22.000 --> 00:27:23.000
You know, it's tricky, because the university
in general discourages you from giving

00:27:26.000 --> 00:27:29.000
alternate exams because of

00:27:29.000 --> 00:27:33.000
- you can imagine the issues
of having an exam that has been

00:27:33.000 --> 00:27:35.000
seen by some number of students before
some other number of students take it.

00:27:35.000 --> 00:27:38.180
Even though we're all bound by the honor code,
it does create a situation where

00:27:38.180 --> 00:27:39.480
there is some temptation.

00:27:39.480 --> 00:27:43.240
It's possible it could be a little bit
early without a lot of gap, but I

00:27:43.240 --> 00:27:46.030
don't think early enough to make alot
of help is the truth.

00:27:46.030 --> 00:27:49.000
We can talk about it.
The current plan is not, I would say.

00:28:03.011 --> 00:28:07.994
A little bit about compilers.
We use C++.

00:28:07.994 --> 00:28:09.050
and we also use

00:28:09.050 --> 00:28:11.480
some custom libraries, which limits us
to distributing on a certain number of platforms

00:28:11.480 --> 00:28:15.070
we've had a good chance to
test on and work with


00:28:15.070 --> 00:28:18.960
The compilers that we have
support for is X Code on the Macintosh.

00:28:18.960 --> 00:28:22.040
xcode is apples free developer tools so

00:28:22.060 --> 00:28:25.050
Anybody who has Mac OS 10 can freely
download that, and install our libraries.

00:28:25.050 --> 00:28:29.000
We're using Microsoft's
Visual Studio Version 2005 on Windows,

00:28:29.000 --> 00:28:32.000
we have an arrangement with Microsoft
where they have distributed the software

00:28:32.000 --> 00:28:35.930
free of charge to students, so if you would
like to install that on your own Windows computer,

00:28:36.000 --> 00:28:38.000
we'll give you some handouts on Friday that tell you

00:28:38.000 --> 00:28:43.510
what to do to get the compiler
and get it installed on your systems.

00:28:43.570 --> 00:28:48.020
Our cluster computers in the dorms
and the libraries and

00:28:48.050 --> 00:28:53.340
the lair both operating systems have both
the compilers and libraries installed,

00:28:53.600 --> 00:28:57.000
so if you work in a cluster,
you don't have to do anything special.

00:28:57.000 --> 00:29:04.000
You just walk up and it's got the
stuff ready to go.

00:29:07.000 --> 00:29:11.000
I'm a Mac person. I've been a Mac
person forever.

00:29:11.000 --> 00:29:13.000
I can't get over the fact that you go to
the start menu to shut the machine down.

00:29:13.000 --> 00:29:17.000
That makes Windows impossible for me to use.

00:29:19.000 --> 00:29:24.970
I would say campus wide, there are more
Windows machines than Macs on campus,

00:29:25.010 --> 00:29:29.000
So if you want to take a popular vote,
You could do that.

00:29:29.000 --> 00:29:33.980
If you want to be on the side of the Mac bigot,
you can come and be with me in X Code.

00:29:44.790 --> 00:29:49.000
I've got ten minutes to tell you a little
bit about C++.

00:29:49.000 --> 00:29:54.040
That is the next journey that we're
going to go on together.

00:29:54.040 --> 00:29:57.000
The first question is:
Why are we doing this to you?

00:29:57.000 --> 00:30:02.000
I just got comfortable with Java and now
you're telling me to throw away my Java
and start over.

00:30:02.850 --> 00:30:07.880
Let's generate a little bit of love for C++.

NOTE Paragraph

00:30:08.000 --> 00:30:10.990
The advantages of early multilingualism.

00:30:10.990 --> 00:30:14.000
- I have two small children at home
that are two and four,

00:30:14.000 --> 00:30:18.000
and I read a lot about bilingualism.

00:30:19.000 --> 00:30:22.000
It's very clear that for natural
languages, when you're

00:30:22.000 --> 00:30:25.000
acquiring a language at those
young ages that that is the

00:30:25.000 --> 00:30:27.840
best time to introduce a second
or third language.

00:30:27.970 --> 00:30:30.920
Where you are building the
pathways and the neurons.

00:30:32.000 --> 00:30:35.000
It's been looked at in terms of programming
languages as well,

00:30:35.000 --> 00:30:38.000
that when you are learning a programming
language, there are certain kind

00:30:38.000 --> 00:30:41.000
of ruts your mind gets into about
the way a language is

00:30:41.000 --> 00:30:45.000
that is based on your early experiences.


00:30:45.000 --> 00:30:48.940
If you spend a very long time working 
only in one language, those ruts get deeper,

00:30:49.000 --> 00:30:52.000
and you have a certain way of thinking.
You're a little bit stuck in that paradigm and its approach.

00:30:52.000 --> 00:30:55.680
What's easy to do in that language,
what's hard to do in that language

00:30:55.830 --> 00:30:59.980
tends to make a stronger impression on
you in a way that makes it harder as you

00:31:00.000 --> 00:31:04.000
grow and explore the languages to kind of get
out of those ruts and shake yourself out of it.

00:31:04.000 --> 00:31:07.930
There's been some pretty good evidence
that somewhere between one

00:31:08.000 --> 00:31:10.960
and two is a good time to think
about branching out

00:31:10.960 --> 00:31:14.000
and starting to think about different 
ways of doing stuff and seeing some

00:31:14.000 --> 00:31:20.230
different syntax and some different ideas
to help build in the flexibility from


00:31:20.230 --> 00:31:26.450
an early age in your career to buy you
some strength later.

00:31:26.520 --> 00:31:31.000
That's part of what we're doing.
Another part of it is actually that a lot of our upper division

00:31:31.000 --> 00:31:36.010
courses rely on a knowledge of
C and C++, that family of languages,

00:31:36.010 --> 00:31:39.000
and that the longer we postpone it,
the more painful it becomes.

00:31:39.000 --> 00:31:43.950
In the later courses where you're learning
about compilers or graphics or networking,

00:31:44.000 --> 00:31:48.000
they don't have the time in those classes to stop and teach you C or C++.

00:31:48.000 --> 00:31:50.930
They need you to know C++ to get the work done.

00:31:51.000 --> 00:31:54.940
Moving the foundation into a programming class

00:31:54.940 --> 00:31:57.000
seems to make the most sense in the context of our curriculum.

00:31:57.000 --> 00:32:00.000
We do switch you over here.

00:32:00.000 --> 00:32:04.000
The good news is that it's not as big a change as it might sound at first glance.

00:32:04.000 --> 00:32:07.000
Java is actually highly derivative of C++ for a start.

00:32:07.000 --> 00:32:10.000
They're kind of cousins in the scheme of language design.

00:32:10.000 --> 00:32:12.000


00:32:12.000 --> 00:32:14.000
They have a lot of syntax.

00:32:14.000 --> 00:32:18.110
How much C++ do you need to know to start?
The answer is zero.

00:32:18.110 --> 00:32:21.000
You don't even need to know what the word means.

00:32:21.000 --> 00:32:22.000
In fact,

00:32:22.000 --> 00:32:25.000
you actually probably know a surprising
amount about C++ just by virtue of what

00:32:25.000 --> 00:32:28.000
you already know just translated a little bit.

00:32:28.000 --> 00:32:32.000
Things like the four loop of Java or the way you declare variables or

00:32:32.000 --> 00:32:35.000
the way parameters are passed into a function

00:32:35.000 --> 00:32:39.000
is exhibited in Java in very much the same way it is in C++.

00:32:39.000 --> 00:32:42.000
There are a bunch of things you already know and you don't even realize.

00:32:42.000 --> 00:32:45.470
It is not assumed that you know C or C++.


00:32:45.590 --> 00:32:49.000
If you happen to already know those things,
you're ahead of the game.

00:32:50.080 --> 00:32:52.000
If you have not,

00:32:52.000 --> 00:32:54.000
then not to worry.

00:32:54.000 --> 00:32:57.000
How much C++ are you going to learn?

00:32:58.000 --> 00:33:00.000
We will spend the first

00:33:00.000 --> 00:33:02.000
three or four lectures

00:33:02.000 --> 00:33:05.000
just talking about how things get expressed differently in C++

00:33:05.000 --> 00:33:07.000
and mostly talking about

00:33:07.000 --> 00:33:12.000
the differences in the libraries.
The syntax itself is quite similar.

00:33:12.000 --> 00:33:15.000
Some of the more extensive changes have to do with how the C++

00:33:15.000 --> 00:33:17.810
string is operated on versus the Java string.

00:33:17.810 --> 00:33:20.000
How you do file input and output reading

00:33:20.000 --> 00:33:23.000
in C++ is a little bit different than the way it's done in Java.

00:33:23.000 --> 00:33:26.000
We'll spend some time saying here are some things you know how to express in one language.

00:33:26.000 --> 00:33:29.000
We're going to teach you how to express them in another language.

00:33:29.000 --> 00:33:31.000
It's just mapping from your previous vocabulary onto a new one.

00:33:32.000 --> 00:33:35.000
Along the way, we will actually introduce some of the C++

00:33:35.000 --> 00:33:38.000
features that we need to support our pedagogical goals.

00:33:38.000 --> 00:33:42.000
We'll be talking about how classes get designed in C++.
We'll see how to use classes.

00:33:44.000 --> 00:33:45.000
those classes, We'll see how to define

00:33:45.000 --> 00:33:49.000
and we'll look at things like templates, which is the C++

00:33:49.000 --> 00:33:52.000
construct for doing generics that you seen in Java - how you can build

00:33:52.000 --> 00:33:56.000
containers that are type unspecific and things like that. We

00:33:56.000 --> 00:34:01.000
will learn a little bit of some of the fancier features of C++ like

00:34:01.000 --> 00:34:02.000
the pass by reference parameter,

00:34:02.000 --> 00:34:05.000
but there's actually a very large amount of C++ that's just off the

00:34:05.000 --> 00:34:07.000
table for us.

00:34:07.000 --> 00:34:11.000
We will not make extensive use of the standard template library or

00:34:11.000 --> 00:34:13.000
the

00:34:13.000 --> 00:34:17.000
fancier features of 'static' and 'const' and a bunch of key words that

00:34:17.000 --> 00:34:20.000
mean nothing to you and should mean nothing to you.

00:34:20.000 --> 00:34:23.000
You will learn enough to have reading familiarity with

00:34:23.000 --> 00:34:26.000
C++ and to be able to express yourself quite well in the subset we're using, but

00:34:26.000 --> 00:34:29.000
it is a subset of C++ that you're being exposed

00:34:32.000 --> 00:34:35.000
to.

00:34:35.000 --> 00:34:39.000
If you find yourself really wanting to

00:34:39.000 --> 00:34:42.000
master C++,

00:34:46.000 --> 00:34:48.000
we are offering

00:34:48.000 --> 00:34:52.000
CS106L. CS106L is a lab companion course that is

00:34:52.000 --> 00:34:55.000
open to students enrolled in 106B or 106X.

00:34:55.000 --> 00:34:57.000
It meets twice a week.

00:34:57.000 --> 00:34:59.000
It's actually on Monday and Wednesday late afternoon.

00:34:59.000 --> 00:35:02.000
It's 4:15 in Hewlett

00:35:02.000 --> 00:35:04.000
103. It's being taught by a veteran section leader

00:35:04.000 --> 00:35:09.000
who is very well versed in C++ and who of his own

00:35:09.000 --> 00:35:13.000
volition volunteered and created this course because

00:35:13.000 --> 00:35:16.000
he himself was a little frustrated as a prior 106 student

00:35:16.000 --> 00:35:19.000
in wanting to get at some of those C++ things that weren't

00:35:19.000 --> 00:35:20.000
fitting with our goals.

00:35:20.000 --> 00:35:23.000
It is a place where you can

00:35:23.000 --> 00:35:26.000
get more exposure to standard C++, do some exercises that help

00:35:26.000 --> 00:35:29.000
you to test out those things and see how those things are expressed and get another

00:35:29.000 --> 00:35:32.000
unit. It's a pass/fail lab course.

00:35:32.000 --> 00:35:35.000
You can also just attend or grab the materials if you just want to look at

00:35:35.000 --> 00:35:35.000
them.

00:35:35.000 --> 00:35:38.000
It's a great way to

00:35:41.000 --> 00:35:43.000
broaden that knowledge of C++ beyond what's

00:35:43.000 --> 00:35:48.000
useful for us in terms of our goals. I'm going

00:35:48.000 --> 00:35:53.000
to ask you some questions, because I don't get to do all the talking.

00:35:53.000 --> 00:35:56.000
How much C++ do you need to know? Some of you may know nothing about it,

00:35:56.000 --> 00:35:58.000
and that is perfectly fine. Some of you probably know something about it or at least

00:35:58.000 --> 00:36:02.000
have heard something about it. I'm going to have you guys tell me

00:36:02.000 --> 00:36:04.000
what it

00:36:05.000 --> 00:36:09.000
is that people tell you about C++ that

00:36:09.000 --> 00:36:13.000
makes you either excited to learn it or frightened to learn it or

00:36:13.000 --> 00:36:15.000
interested in how it works. It's

00:36:15.000 --> 00:36:17.000
what Java is based off of. It is what Java is

00:36:17.000 --> 00:36:20.000
based

00:36:20.000 --> 00:36:24.000
off of. That should be a little reassuring

00:36:24.000 --> 00:36:28.000
that there is a syntax there that got adopted with some minor

00:36:28.000 --> 00:36:31.000
changes. It should feel

00:36:31.000 --> 00:36:34.000
more familiar than different when you look at it.

00:36:34.000 --> 00:36:37.000
It was very strongly influenced by a generation of

00:36:37.000 --> 00:36:39.000
programmers who C++ was their native language who designed the

00:36:39.000 --> 00:36:42.000
Java language. That's a good thing to know. What else do you know

00:36:42.000 --> 00:36:47.000
about C++?

00:36:47.000 --> 00:36:49.000
It's extended

00:36:50.000 --> 00:36:53.000
C. Yes. It's extended C. Here's how it fits in the spectrum.

00:36:53.000 --> 00:36:56.000
C is kind of a 1970s creation. C++ is a

00:36:56.000 --> 00:36:58.000
decade later.

00:36:58.000 --> 00:37:01.000
C is the language which it is based on. It is an extended C. It's

00:37:01.000 --> 00:37:05.000
called a superset. Everything that compiles and works in C

00:37:05.000 --> 00:37:07.000
still exists in C++, but then they added a bunch of features.

00:37:07.000 --> 00:37:10.000
Not only did they add a bunch of features but they tried to fix some of the things

00:37:10.000 --> 00:37:13.000
about C++ by replacing existing things. For example, there's some

00:37:13.000 --> 00:37:17.000
string handling in C that's kind of very primitive. They added a string

00:37:17.000 --> 00:37:18.000
object

00:37:18.000 --> 00:37:22.000
with much cleaner handling and safer semantics into the C++, but they kind of

00:37:22.000 --> 00:37:23.000
left the old one around.

00:37:23.000 --> 00:37:26.000
Some parts of C++ feel a little strange

00:37:26.000 --> 00:37:32.000
because of this history to it - the legacy of incorporating everything C was plus the stuff

00:37:32.000 --> 00:37:35.000
means at times there's a little bit of weirdness there. It also means

00:37:35.000 --> 00:37:39.000
that the language, as a result, is very large.

00:37:40.000 --> 00:37:44.000
C's

00:37:44.000 --> 00:37:47.000
type safety

00:37:47.000 --> 00:37:52.000
and runtime features were extended by what

00:37:52.000 --> 00:37:56.000
got

00:37:56.000 --> 00:38:00.000
added in C++. A friend of mine told me that [inaudible]. That's a

00:38:07.000 --> 00:38:08.000
good thing

00:38:08.000 --> 00:38:09.000
to know.

00:38:09.000 --> 00:38:13.000
C++ might be a little bit more dangerous than Java.

00:38:13.000 --> 00:38:17.000
That is true. Java is very

00:38:17.000 --> 00:38:21.000
concerned with

00:38:21.000 --> 00:38:25.000
safety, in particular since Java was designed for web

00:38:25.000 --> 00:38:27.000
delivery of content. It was very important that the program have

00:38:27.000 --> 00:38:29.000
very constrained

00:38:29.000 --> 00:38:31.000
features on what it can and can't do,

00:38:31.000 --> 00:38:35.000
and so as a result, Java tends to be very parental. When you

00:38:35.000 --> 00:38:38.000
forget to initialize a variable or forget to

00:38:38.000 --> 00:38:39.000
return from a function,

00:38:39.000 --> 00:38:41.000
Java's

00:38:41.000 --> 00:38:45.000
very aggressive about saying hey, you've got to fix this. C++ is a little

00:38:46.000 --> 00:38:47.000
less

00:38:47.000 --> 00:38:51.000
parental. Here's the overly protective mom, helicopter mom,

00:38:51.000 --> 00:38:54.000
the ones who stand. That's Java. Java's making sure - oh, are you okay,

00:38:54.000 --> 00:38:57.000
sweetie? Let me stand here

00:38:57.000 --> 00:39:01.000
in case you fall. C++ is crack mom. She's like yeah, I'm over

00:39:01.000 --> 00:39:05.000
here with my friends. Don't play

00:39:05.000 --> 00:39:06.000
with

00:39:06.000 --> 00:39:08.000
the kitchen knives.

00:39:08.000 --> 00:39:11.000
It's a professional's tool,

00:39:11.000 --> 00:39:13.000
and professionals don't want to feel encumbered. There are certain things they want

00:39:13.000 --> 00:39:16.000
to do that require some of this

00:39:16.000 --> 00:39:19.000
low-level access, and safety usually comes at a cost.

00:39:19.000 --> 00:39:23.000
Any sort of feature where the language is double-checking for you is taking time and

00:39:23.000 --> 00:39:26.000
efficiency. There's a cost associated with that. Every time you want

00:39:26.000 --> 00:39:28.000
to get something out of an array,

00:39:28.000 --> 00:39:30.000
it's checked to make sure that that number was

00:39:30.000 --> 00:39:34.000
not off either end. Every array access costs you a little bit more.

00:39:34.000 --> 00:39:35.000
C++ says

00:39:35.000 --> 00:39:38.000
I'm not going to charge everybody that penalty. If you actually have the bad sense

00:39:38.000 --> 00:39:43.000
to write a program that does those things, you deserve to be punished.

00:39:43.000 --> 00:39:47.000
As a result, you will at some

00:39:47.000 --> 00:39:49.000
point in this quarter get to experience some of that firsthand. Some of

00:39:49.000 --> 00:39:53.000
it is a growth experience. Some

00:39:53.000 --> 00:39:56.000
of it can be frustrating. It is part of what

00:39:56.000 --> 00:39:58.000
professional tools often look like. They are making these tradeoffs

00:39:58.000 --> 00:40:01.000
of efficiency over safety that

00:40:01.000 --> 00:40:04.000
put more of the work back on you as the programmer to be a little more attentive on

00:40:04.000 --> 00:40:05.000
those things.

00:40:05.000 --> 00:40:09.000
You can write programs that crash in very spectacular ways

00:40:09.000 --> 00:40:14.000
much more interesting and varied and dangerous than the kind of things you can do

00:40:18.000 --> 00:40:21.000
in Java. Good to know. You want to

00:40:21.000 --> 00:40:29.000
use

00:40:29.000 --> 00:40:29.000
pointers.

00:40:29.000 --> 00:40:31.000
You're going to get to use pointers.

00:40:31.000 --> 00:40:35.000
Pointers are really neat, and they're also very challenging. Pointers are these

00:40:35.000 --> 00:40:37.000
ways of building these very flexible and amazing

00:40:37.000 --> 00:40:40.000
data structures - the kind of things that we're going to try to build. At some

00:40:40.000 --> 00:40:43.000
point, they are going to be the only way to achieve those things well, so building

00:40:43.000 --> 00:40:46.000
these things called trees, graphs and lists rely on understanding

00:40:46.000 --> 00:40:49.000
a mastery of the pointer type. The pointer type is complicated, and it's part of

00:40:49.000 --> 00:40:51.000
that danger thing, which is

00:40:51.000 --> 00:40:53.000
having access to

00:40:53.000 --> 00:40:57.000
rearranging memory by virtue of addresses opens up a lot of

00:40:57.000 --> 00:40:59.000
opportunity for there to be mistakes.

00:40:59.000 --> 00:41:02.000
Mistakes can be made in the passive voice

00:41:02.000 --> 00:41:06.000
that have consequences. You'll get to experience firsthand what that's like.

00:41:06.000 --> 00:41:09.000
There's joy in it, because getting it right is awesome, and there are things that you can

00:41:09.000 --> 00:41:12.000
achieve that are really extraordinary with pointers, but

00:41:12.000 --> 00:41:13.000
when it's not working,

00:41:13.000 --> 00:41:17.000
it can

00:41:17.000 --> 00:41:18.000
be frustrating. You're getting a

00:41:18.000 --> 00:41:22.000
little

00:41:22.000 --> 00:41:25.000
bit of both. It turns out C++ does not have a graphics system built

00:41:25.000 --> 00:41:26.000
into it.

00:41:26.000 --> 00:41:29.000
Java is actually distinguished from previous

00:41:29.000 --> 00:41:32.000
languages. Java tries to solve all problems. Traditionally, a

00:41:32.000 --> 00:41:33.000
programming language tends to have a set

00:41:33.000 --> 00:41:34.000
of libraries that have

00:41:34.000 --> 00:41:38.000
facilities for data management, reading and writing files and sometimes some

00:41:38.000 --> 00:41:42.000
networking, but they don't tend to actually solve application layer problems. That

00:41:42.000 --> 00:41:46.000
tended to be a different piece of technology. The Mac

00:41:46.000 --> 00:41:49.000
OS might offer a graphics library that was written in C++, but C++

00:41:49.000 --> 00:41:50.000
the language

00:41:50.000 --> 00:41:53.000
didn't have a windowing system or graphics system.

00:41:53.000 --> 00:41:55.000
C++ does not have those features

00:41:55.000 --> 00:41:56.000
itself,

00:41:56.000 --> 00:41:58.000
so any C++ compiler

00:41:58.000 --> 00:42:02.000
you get comes with these basic things about handling files and managing these types of

00:42:02.000 --> 00:42:05.000
data structures, but it does not come a priori with a bunch of graphics routines.

00:42:05.000 --> 00:42:07.000
That said,

00:42:07.000 --> 00:42:09.000
Windows and Mac and Linux and all these things have graphics routines that are

00:42:09.000 --> 00:42:12.000
written in C++, but they're all different. To say what are they

00:42:12.000 --> 00:42:13.000
like

00:42:13.000 --> 00:42:15.000
relative to Java? They're all different relative

00:42:15.000 --> 00:42:16.000
to Java. It's not standardized.

00:42:18.000 --> 00:42:21.000
There's a wide variety of them out there, and

00:42:21.000 --> 00:42:24.000
they tend to have a lot of very impressive and different solved

00:42:24.000 --> 00:42:27.000
problems, because C++ has a longer history than Java that a lot

00:42:27.000 --> 00:42:30.000
of problems have been solved in C++ that are available to you,

00:42:30.000 --> 00:42:32.000
too. There's a lot of existing code

00:42:32.000 --> 00:42:36.000
other than what you might think is standard.

00:42:38.000 --> 00:42:42.000
I

00:42:42.000 --> 00:42:43.000
will

00:42:43.000 --> 00:42:47.000
see you on Friday, and we'll be seeing some C++. If you have

00:42:47.000 --> 00:42:58.000
questions about your situation, come and talk to me now.