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This presentation is delivered by the[br]Stanford Center for Professional Development

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Hi! Welcome, welcome to CS106B,[br]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[br]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[br]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[br]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,[br]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[br]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[br]of what our course is about,

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tell you a little bit about the[br]administration and logistics

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most of that stuff is pretty ordinary,[br]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[br]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[br]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[br]sequence here at Stanford.

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

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when you are interested in[br]learning more about programming.

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We have a two-quarter sequence,[br]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,[br]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[br]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[br]you are a CS major yet.

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

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At Stanford right,[br]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[br]and to feel unencumbered by having made some

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

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

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funnel you one way or[br]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 [br]that help to make that work.

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

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

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there's kind of a strong influence[br]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[br]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++,[br]two of the most prevalent languages

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

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

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

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You really are building skills[br]that have applicability here and[br]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[br]substitute courses

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

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is tackling this part of it,[br]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[br](Monkies shakespeare, whatnot)

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

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Well +1, -1, what if I move it here[br]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,[br]might produce a program that from

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external appearances works.

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

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It's not well structured.[br]It's not well commented.

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It's not easy to understand.[br]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[br]engineers

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

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good, well designed software, [br]not just working software.

0:11:56.000,0:11:57.000
We will be giving you feedback on

0:11:57.000,0:12:00.000
both the correctness and[br]functionality of your code

0:12:01.740,0:12:05.000
as important if not more so,

0:12:05.000,0:12:08.000
also on how well we think you did[br]at designing and implementing and

0:12:08.000,0:12:11.030
writing code that is of[br]a high quality.

0:12:11.030,0:12:12.030
We make a big deal out of that.

0:12:12.030,0:12:14.000
That is something that is not[br]always shared by other classes,

0:12:14.000,0:12:16.510
and so in particular, someone who is self-taught

0:12:16.510,0:12:20.000
or in a class that didn't emphasize this[br]might feel that there's a little bit of a gap there[br]

0:12:20.000,0:12:21.000
we need to make[br]that up with you,

0:12:21.000,0:12:23.490
and we can work with you.

0:12:23.490,0:12:26.000
This is a very individual thing,[br]because there's not one good example of

0:12:26.000,0:12:28.000
the perfect style

0:12:28.000,0:12:31.000
in the way that a lot of different people

0:12:31.000,0:12:34.000
express themselves in written communication

0:12:34.000,0:12:34.990
very well but differently.

0:12:34.990,0:12:36.500
The same thing is true about programs.

0:12:36.500,0:12:40.000
You will have your own unique style,[br]and we'll work with you to coach you on getting your

0:12:40.000,0:12:44.010
style to come through and[br]be beautiful and elegant.

0:12:46.000,0:12:50.000
This kind of comes back to point 1[br]we make heavy use of undergraduate

0:12:50.000,0:12:53.000
section leaders as mentors in this program.

0:12:53.000,0:12:59.000
We have a staff of 50 or so, undergraduates[br]who work with the 106A, B and X courses as a team.

0:12:59.000,0:13:02.000
They have specific responsibilities with their section,

0:13:02.000,0:13:06.000
so mentoring and grading and meeting with

0:13:06.000,0:13:09.000
sectionees to give individualized[br]feedback on their programs

0:13:09.000,0:13:10.000
as well as

0:13:10.000,0:13:13.760
answering questions, solving problems,[br]being in the lair 30 plus hours.

0:13:13.760,0:13:16.000
They're most weekday nights about six hours

0:13:16.000,0:13:17.000
and often

0:13:17.000,0:13:20.000
well past the midnight when it's supposed to cut off[br]solving people's problems,

0:13:20.000,0:13:23.000
helping when you get stuck,[br]answering your questions

0:13:23.000,0:13:26.000
and making sure you're all[br]making forward progress.

0:13:26.000,0:13:29.000
That comes back to point 1.

0:13:29.000,0:13:31.000
In some universities where they're[br]choosing to use their intro course as a weeder,

0:13:31.000,0:13:33.690
it's like let's separate the wheat[br]from the chaff early

0:13:33.690,0:13:35.000
and let's make it really hard and not

0:13:35.000,0:13:38.000
provide too much support,[br]and that way we'll make sure we get the people we want.

0:13:38.000,0:13:41.000
We have a different idea.

0:13:41.000,0:13:42.000
Programming is hard,[br]especially when you're learning.

0:13:42.000,0:13:46.000
There's a lot of complexity to master,[br]and there are a lot of details that can

0:13:46.000,0:13:49.000
interfere with moving forward,[br]and we don't want you

0:13:49.000,0:13:52.000
to get stuck on something that[br]we can very easily resolve for you.

0:13:52.000,0:13:55.980
So make sure you have accessible[br]staff members in person, in email

0:13:56.000,0:13:58.000
and regularly in section

0:13:58.000,0:14:04.000
to help get through the roadblocks[br]and keep you moving forward.

0:14:04.000,0:14:08.000
What do you need to know to be[br]sure you're going to do well?

0:14:08.000,0:14:12.000
There are people who think to[br]be a good computer programmer,

0:14:12.000,0:14:16.000
you need to be good at math,[br]logic, and drinking Jolt.

0:14:16.000,0:14:22.010
I think it it comes down to[br]personality traits than any

0:14:22.020,0:14:24.500
particular technique or skill.

0:14:24.500,0:14:26.000
You don't need to be good at math.

0:14:26.000,0:14:29.000
How much calculus and trig shows up in this?

0:14:29.000,0:14:32.000
Not very much.[br]A little bit of logic - that helps.

0:14:32.000,0:14:36.990
I think it comes down to traits like[br]curiosity and determination and hard work.

0:14:37.000,0:14:37.980
Starting early,

0:14:37.980,0:14:41.000
asking questions[br]when you don't understand something,

0:14:41.000,0:14:43.510
trying to solve the problem by logic[br]I think is very valuable

0:14:43.510,0:14:45.000
Knowing how to think,[br]how to make steps

0:14:45.000,0:14:47.960
why this case works and[br]why that case doesn't work

0:14:47.970,0:14:51.720
thinking about that logically

0:14:51.755,0:14:55.735
(well its like the movie theater now you guys will all go to sleep)[br](oh look they came back) [lights]

0:14:57.000,0:15:01.120
I think these are the skills[br]that serve you the best in this class

0:15:01.120,0:15:04.010
And probably[br]every other thing you'd want to tackle.

0:15:04.010,0:15:08.000
There is a lot of time that will be spent[br]to master this.

0:15:08.000,0:15:11.110
I can talk about programming all I want,[br](bla, bla, bla)

0:15:11.110,0:15:13.000
and you can go oh, yeah, that makes a[br]lot of sense.

0:15:13.000,0:15:16.000
But when you go to write it yourself,[br]it's a very different experience.

0:15:16.000,0:15:19.960
That's where being[br]focused and staying on task

0:15:20.000,0:15:25.040
and getting help when you get stuck[br]can help you move through that

0:15:25.080,0:15:28.080
(Any questions about 106?)[br](What we do,)

0:15:28.090,0:15:32.070
(Why we do what we do.)[br](You guys have nothing to say)

0:15:32.070,0:15:34.070
(your afraid of having your)[br](voice recorded aren't you?)

0:15:34.070,0:15:39.020
(For all time your parents will come and see)[br](that you come to class you can prove it)

0:15:40.010,0:15:44.000
My unbiased opinion about why 106B is[br]one of the best courses at Stanford

0:15:44.000,0:15:47.000
(of course I am not at all unbiased)

0:15:47.000,0:15:50.000
it's going to be

0:15:50.000,0:15:53.000
totally obvious when I say these things,[br]and you guys are going to have to go

0:15:53.000,0:15:54.960
along with it.[br]I'm actually a

0:15:55.000,0:15:58.000
geek, really big time,[br]and I happen to love programming.

0:15:58.000,0:16:00.000
That's why I'm a perfect fit for teaching this class.

0:16:00.000,0:16:01.490
I have taught 106 B or X more than I've taught

0:16:01.490,0:16:04.000
any other class that I've taught at[br]Stanford in my time here,

0:16:04.000,0:16:06.330
and that's because each quarter[br]when we're setting the schedule,

0:16:06.330,0:16:08.000
I say give me B.[br]Give me X.

0:16:08.000,0:16:09.000
Because there's no better course to teach.

0:16:09.000,0:16:12.000
Programming is just awesome.

0:16:12.000,0:16:15.000
If you love programming,[br]I think there's almost nothing better to do in the world.

0:16:15.000,0:16:17.510
You have this task.[br]You're trying to get there.

0:16:17.510,0:16:19.170
You're coding.[br]You're making stuff happen.

0:16:19.170,0:16:21.940
You're testing, iterating you're running.[br]You see stuff.

0:16:21.950,0:16:25.020
You build things.[br]When you're done, you know it works.

0:16:25.020,0:16:28.000
That feeling when you write a paper and go[br]"was it good enough?"

0:16:28.000,0:16:30.000
"well I dont know"[br]you could probably go bolster up this argument

0:16:30.000,0:16:32.280
When a program works,[br]you know it.

0:16:32.290,0:16:36.000
It does what it's supposed to do.[br]It gets the right answer.

0:16:36.000,0:16:38.020
It plays the game.[br]It solves the problem.

0:16:38.020,0:16:42.000
Finding and fixing that last bug[br]- although debugging is one of the last

0:16:42.000,0:16:45.000
aspects of programming a lot of people bemoan about;[br]I happen to think that if you

0:16:45.000,0:16:49.000
are driven by debugging,[br]that is one of the most awesome detective stories

0:16:49.000,0:16:53.980
Trying to figure out why it happened when you did this,[br]when you moved that why it went this way

0:16:54.000,0:16:57.000
and what this effect caused[br]and understanding once you make the fix how it fixes it

0:16:57.000,0:16:58.930
staying up late.

0:16:58.930,0:17:02.000
I have stayed up late more nights debugging[br]than anything else in my life,

0:17:02.000,0:17:04.000
and I'm not sad about that at all.

0:17:04.000,0:17:08.000
That means I'm in the right place.[br]Hopefully, some of that resonates with you.

0:17:09.020,0:17:12.000
If that sounds really awful to you,

0:17:12.000,0:17:14.000
hopefully we can change your mind a bit.

0:17:14.000,0:17:18.000
That is, in some ways,[br]part of what drives computer science is this

0:17:18.000,0:17:21.000
wanting to build things.[br]We are engineers.

0:17:21.000,0:17:24.000
We have this computer science name.[br]Just remember

0:17:24.000,0:17:29.000
- any subject[br]that's name is something science is not a science.

0:17:29.000,0:17:31.950
We're trying to puff ourselves up a bit.

0:17:32.000,0:17:34.000
We do a lot of really great work,

0:17:34.000,0:17:37.000
and there are a lot of neat scientific[br]principles and theories that

0:17:37.000,0:17:38.000
underpin what we do,

0:17:38.000,0:17:41.000
but in the end,[br]I think what drives a lot of us is just

0:17:41.000,0:17:44.990
the engineering[br]- building stuff that is really neat.

0:17:45.010,0:17:49.000
It kind of reminds me that my[br]husband's a mechanical engineer, and so I

0:17:49.000,0:17:52.220
used to be envious, because[br]he would always build things.

0:17:52.220,0:17:57.000
M.E.'s always toting foam core around the campus[br]on their paper bicycles and stuff, and it's like

0:17:57.000,0:18:00.000
they build all these things.[br]Now, having watched all the things he builds, it's like

0:18:00.000,0:18:02.000
mechan-e is really hard.[br]You need all these materials.

0:18:02.000,0:18:05.320
You need all these tools.[br]You need this mill, you need this lathe

0:18:05.320,0:18:07.430
You need the hotmelt glue gun,[br]which burns the heck out of your fingers

0:18:07.430,0:18:08.160
anytime you touch it.

0:18:08.160,0:18:10.660
To build anything.

0:18:10.930,0:18:12.560
In computer science, you don't need anything.

0:18:12.560,0:18:14.000
You need a compiler and you need a computer.

0:18:14.000,0:18:15.030
You need your thought.

0:18:15.030,0:18:18.000
It's like an abstraction we built out of our brains.

0:18:18.000,0:18:20.000
There's this relatively small set of things[br]that you need to master

0:18:20.000,0:18:23.990
and then you can combine them in these very[br]sophisticated and interesting ways to solve all sorts of problems.

0:18:24.000,0:18:26.000
There's a very low overhead,

0:18:26.000,0:18:30.000
and the range of things you can attack[br]with the same set of skills is huge.

0:18:30.000,0:18:36.020
Every domain out there can benefit from somebody[br]applying computers in a useful way without fail.

0:18:36.020,0:18:39.080
There's all sorts of problems[br]where technology is part of the answer

0:18:39.080,0:18:41.000
not the only answer,[br]but certainly something that you can take

0:18:41.000,0:18:44.000
whatever interest you have[br]and combine it with computer science

0:18:44.000,0:18:47.000
and construct something cool.

0:18:47.000,0:18:51.000
I happen to think that what[br]happens in the second course is amazing.

0:18:51.000,0:18:54.000
The first course,[br]you've kind of got to get up to speed,

0:18:54.000,0:18:57.000
and there's a lot of basic material[br]that needs to get covered,

0:18:57.000,0:19:00.000
and it does set you on the right path,[br]but in this course, we really

0:19:00.000,0:19:04.000
get to blossom beyond the basic things.

0:19:04.000,0:19:07.000
There are a bunch of really neat[br]and very accessible techniques

0:19:07.000,0:19:11.000
that a second quarter student can understand[br]and master and do really cool things with.

0:19:11.000,0:19:14.050
You can learn how to do something like[br]create a database

0:19:14.050,0:19:17.000
that has a million entries

0:19:17.000,0:19:20.900
and then ask for somebody by name and be able to[br]instantaneously be able to find that name.

0:19:20.900,0:19:23.000
Not by looking through a million[br]entries trying to find that name

0:19:23.000,0:19:26.000
Change the size of it.[br]Make it ten million, a billion, and still be able to

0:19:26.000,0:19:29.000
provide that kind of instantaneous access.[br]You're going to learn how to do that.

0:19:29.000,0:19:32.000
The technique is not some superhuman thing.

0:19:32.000,0:19:34.000
It's something very clever, admittedly,

0:19:34.000,0:19:36.000
but it's very accessible.

0:19:36.000,0:19:40.000
Taking that same million thing and[br]learning how to sort it efficiently.

0:19:40.000,0:19:42.000
What if you happen to know things about how it's[br]almost sorted but just a little but out of sorts?

0:19:42.000,0:19:47.000
Are there ways you can actually make it[br]even faster to put it in sorted order?

0:19:47.000,0:19:50.000
There are techniques, for example,[br]like recursion that take on problems that

0:19:50.000,0:19:53.000
you might not have any idea when you[br]first look at the problem how to solve

0:19:53.000,0:19:57.450
but once you've got your head around recursion,[br]you can look at that and say

0:19:57.450,0:20:01.030
"I can write a five line function[br]that will solve that problem."

0:20:01.030,0:20:05.669
This is the kind of power we're going to[br]give you with our quarter together.

0:20:05.669,0:20:10.000
There's a bunch of really amazing[br]theoretical and algorithmic stuff to explore.

0:20:10.000,0:20:14.000
That really increases the kind of things[br]you can do with programming.

0:20:14.000,0:20:17.840
I'm particularly fond of it.

0:20:18.010,0:20:20.010
[br]As always, I think

0:20:20.010,0:20:23.000
the section leading program that we have[br]created and built at Stanford

0:20:23.000,0:20:27.030
Is a huge part of what makes our 106[br]courses so successful,

0:20:27.030,0:20:28.000
and so

0:20:28.000,0:20:32.990
having somebody who's individually[br]working with you, meeting with you weekly

0:20:34.000,0:20:37.000
and giving you that feedback that's[br]individualized and personalized for you

0:20:37.000,0:20:41.000
and helping you get through the rough spots[br]is a lot of what helps to make the experience

0:20:41.000,0:20:44.000
very fun and very personal, too.

0:20:44.000,0:20:48.910
What section leaders do I have here?[br]Any? Not a one.

0:20:49.000,0:20:52.000
Those fabulous section leaders.[br]Where are they again? section leaders?

0:20:52.000,0:20:54.030
Did i say they were fabulous?[br]I meant. <i>laughs</i> Uhh no.

0:20:54.030,0:20:57.000
We haven't yet identified who's going[br]to what class, so maybe they're all

0:20:57.000,0:21:00.851
thinking they're going to go somewhere else,[br]but they're wrong. We'll get some.

0:21:03.940,0:21:05.000
106B - great. You agree?

0:21:05.000,0:21:07.000
Have I convinced you?

0:21:07.000,0:21:10.000
Is anybody still hesitant?

0:21:13.000,0:21:16.000
Is it a lot of work?[br]Oh, no. <i>laughs</i>

0:21:16.000,0:21:19.000
I just exude it. Osmosis. you learn it.

0:21:21.980,0:21:24.920
Let me tell you a little bit about logistics.

0:21:26.000,0:21:30.000
There are some random things you may want[br]to know about how the class works.

0:21:30.000,0:21:34.000
That the first day I am supposed to do.[br]

0:21:34.000,0:21:38.360
We're going to meet here[br]Monday, Wednesday, Friday 2:15 to 3:05.

0:21:38.360,0:21:41.920
In glorious download[br][ FIXME ] audiotorium

0:21:41.930,0:21:45.060
It looks like we almost[br]exactly fit in our classroom,

0:21:45.060,0:21:47.790
which means we're all[br]going to be very friendly and cozy.

0:21:47.790,0:21:51.131
The lectures are being taped[br]and are available online,

0:21:51.131,0:21:56.540
and so that has the neat side effect that[br]you can watch them and review them later.[br]

0:21:56.540,0:21:58.000
You could watch them lots of times.

0:21:58.000,0:22:01.000
It also means that if it were pouring rain and[br]you were sitting at home in your bunny slippers,

0:22:01.000,0:22:04.000
you could just say hey,[br]I'm not going outside and you could

0:22:04.000,0:22:06.000
turn on your computer and watch.

0:22:06.000,0:22:09.000
I'm a big fan of having you come in person.[br]That's because I don't want to

0:22:09.000,0:22:11.000
lecture to an empty room.

0:22:11.000,0:22:14.000
I also think there's an interaction there

0:22:14.190,0:22:19.000
that I'm fond of, and so I hope that you[br]will make every effort to attend in person[br]as much as you can.

0:22:22.010,0:22:26.990
It is nice to know that if you do miss a lecture or you

0:22:27.000,0:22:29.940
get caught up with something, you'll have a chance to review it later online.

0:22:30.000,0:22:32.000
We will have sections that will meet once a week,

0:22:32.000,0:22:34.970
just like 106A.

0:22:35.000,0:22:38.000
The section leader who meets with you is the one

0:22:38.000,0:22:41.000
who will be grading your programs and sitting with you[br]and doing the conferences.

0:22:41.000,0:22:45.940
What you need to do to get yourself[br]into a section - there are several section times listed.

0:22:45.960,0:22:47.960
They are totally bogus. (so ignore that)

0:22:51.000,0:22:53.000
What you do is you go to the online[br]- if you go to our class webpage, there's a link that tells

0:22:53.000,0:22:56.000
you how to sign up for a section.[br]The section times aren't up right now, but they will go up tomorrow,

0:22:56.000,0:22:58.000
and they'll be up through the weekend.[br]You go in and put in your preferences

0:22:58.000,0:23:03.930
about what times fit your schedule or not,[br]and there's this big computer program

0:23:04.000,0:23:08.790
that does this magic matching that gets[br]everyone into a section that fits their schedule.

0:23:08.880,0:23:11.880
That will happen early next week.

0:23:14.000,0:23:18.850
The signups will be up from Thursday at 5:00[br]until Sunday at 5:00.

0:23:18.960,0:23:22.000
If by Sunday at 5:00[br]you've got your schedule fixed, then you're fine.

0:23:22.000,0:23:25.000
If you happen to change after Sunday at 5:00 and after the assignments have been made,

0:23:25.000,0:23:27.000
at that point, it's a little bit harder.

0:23:27.000,0:23:28.000
We can make adjustments, but it's on a very case-by-case basis.[br]

0:23:28.000,0:23:31.000
Where we have space and where we can accomodate you.

0:23:31.000,0:23:33.000
The best thing you can do

0:23:33.000,0:23:36.000
is by Sunday at 5:00 have a pretty firm idea[br]about what you can and can't do.

0:23:36.000,0:23:37.000
There's a list of preferences,[br]so maybe what you can do

0:23:37.000,0:23:40.000
is pick things that you know will work no matter

0:23:40.000,0:23:41.000
what happens.

0:23:41.000,0:23:44.000
for antyhing that is variable if you just dont offer things that you know might

0:23:44.000,0:23:44.840
go away

0:23:44.980,0:23:49.930
so there is a list of 20 times and you say I can make these 5

0:23:49.930,0:23:52.390
And that way you wont get yourselves in trouble

0:23:52.390,0:23:54.910
in things that might change.

0:23:55.000,0:23:59.000
The workload - everybody wants[br]to know how much work.[br]

0:23:59.000,0:24:02.000
It's a five-unit class, and[br]it's a five unit engineering class.

0:24:04.000,0:24:06.000
You get your five units worth,

0:24:06.000,0:24:09.990
I would say, so don't worry about that. I won't shortchange you.

0:24:11.010,0:24:15.000
We have programming assignments not quite weekly.[br]I think there are seven of them across

0:24:15.000,0:24:18.960
ten weeks, so you can calculate it out.[br]It's about a week and a third

0:24:19.000,0:24:20.000
for any particular one.

0:24:20.000,0:24:22.030
The students report

0:24:22.030,0:24:25.000
that it's about a 15-20 hour project, each of them.

0:24:25.000,0:24:28.000
Some people get them done in less than that.[br]Some people take a little bit more.

0:24:28.000,0:24:33.030
I would say that's kind of the[br]mode range for what people are reporting.

0:24:33.030,0:24:37.000
I do think that of the people who report less,[br]some of those are

0:24:37.000,0:24:41.000
people who are naturally gifted,[br]but a lot of it has to do with your habits

0:24:41.000,0:24:43.000
about how you work and[br]how you make progress, so

0:24:43.000,0:24:46.000
if you are one of the people who feels [br]you might be more likely to be on the other

0:24:46.000,0:24:49.000
end, you can come and talk to[br]me and I can give you some suggestions.

0:24:49.000,0:24:55.630
Choosing to work in the lair where the[br]helpers are on duty has really positive effects

0:24:55.630,0:24:58.000
effects in that when you get stuck,[br]you have easy access to

0:24:58.000,0:24:59.000
somebody helping you work through it

0:24:59.000,0:25:02.000
rather than spending an hour or two[br]fighting something that turns out to be

0:25:02.000,0:25:05.000
simple but required knowing something[br]that you didn't yet know.

0:25:05.000,0:25:10.250
I'm a big fan of learning things yourself.[br]There's also a time when a well-placed

0:25:10.590,0:25:14.000
bit of advice from somebody[br]can save you a lot of time.

0:25:15.000,0:25:22.160
There will be a midterm and a final exam.[br]They'll both be in class, open book, open notes.

0:25:22.160,0:25:24.010
The midterm is actually technically out of class.

0:25:24.010,0:25:28.870
have it at night because we need more than[br]a 50-minute period to get any coverage of that.

0:25:28.870,0:25:31.067
Our final exam is scheduled in[br]our university-scheduled slot.

0:25:31.067,0:25:36.000
Sadly, that is at the very[br]end of the exam week,

0:25:36.000,0:25:37.980
but that's when the registrar put us,[br]and that's when we need to go.

0:25:38.030,0:25:44.010
You may want to take a look at that before[br]you head off to Acapulco for spring break.

0:25:44.010,0:25:45.010
you need to make sure[br]you are here for the exam.

0:25:45.010,0:25:48.980
Male audience: Is the course leader available online?

0:25:48.980,0:25:53.060
Unfortunately, our publisher will not allow me to distribute the course leader electronically.

0:25:54.000,0:25:57.000
They're not exactly very in the modern age on this.

0:26:00.080,0:26:02.000
I'm working on it is the truth.

0:26:02.000,0:26:06.040
By the time the world sees this, hopefully, we will have some other strategy.

0:26:06.040,0:26:08.800
We currently are in negotiations.

0:26:08.880,0:26:11.000
The nice thing about the course reader is that[br]we have not changed it in the last year.

0:26:11.000,0:26:14.000
If you know somebody who has[br]it from last fall or last spring.

0:26:14.000,0:26:18.000
it has some minor edits and typos that were fixed,

0:26:18.000,0:26:20.000
so if you can get a hold of an old one, it's good.

0:26:20.000,0:26:23.100
We are getting no royalties on it.

0:26:23.100,0:26:26.950
We're publishing it at production cost, so where it

0:26:26.950,0:26:31.970
would have been a $100.00 textbook[br]had it been bound and all snappy.

0:26:32.000,0:26:36.000
you're just getting what it cost to photocopy and bind the thing, and Eric and

0:26:36.070,0:26:39.980
I are eating ramen.

0:26:40.000,0:26:42.000
It's hopefully cheap enough that

0:26:42.000,0:26:44.000
you can find a way to get to one

0:26:44.000,0:26:47.500
or get an old one without it being[br]too much of an obstacle.

0:26:49.000,0:26:52.800
People in general find the course[br]reader to be an asset.

0:26:52.800,0:26:54.060
We do say it's required reading.

0:26:54.060,0:26:58.530
It does have a lot of material that's very[br]useful in understanding the course.

0:26:58.610,0:27:02.000
There are other people who[br]don't make as big a use of it,

0:27:02.000,0:27:05.000
but there are some sections that[br]are really very valuable

0:27:05.000,0:27:08.020
and other ones that may be more[br]or less depending on your learning style.

0:27:08.020,0:27:11.800
Whether you appreciate more of a chance to[br]read background material and more examples.

0:27:11.800,0:27:15.000
There's also a lot of good sample problems in it

0:27:15.000,0:27:18.600
and review questions in it that help to test your understanding.

0:27:22.000,0:27:23.000
You know, it's tricky, because the university[br]in general discourages you from giving

0:27:26.000,0:27:29.000
alternate exams because of

0:27:29.000,0:27:33.000
- you can imagine the issues[br]of having an exam that has been

0:27:33.000,0:27:35.000
seen by some number of students before[br]some other number of students take it.

0:27:35.000,0:27:38.180
Even though we're all bound by the honor code,[br]it does create a situation where

0:27:38.180,0:27:39.480
there is some temptation.

0:27:39.480,0:27:43.240
It's possible it could be a little bit[br]early without a lot of gap, but I

0:27:43.240,0:27:46.030
don't think early enough to make alot[br]of help is the truth.

0:27:46.030,0:27:49.000
We can talk about it.[br]The current plan is not, I would say.

0:28:03.011,0:28:07.994
A little bit about compilers.[br]We use C++.

0:28:07.994,0:28:09.050
and we also use

0:28:09.050,0:28:11.480
some custom libraries, which limits us[br]to distributing on a certain number of platforms

0:28:11.480,0:28:15.070
we've had a good chance to[br]test on and work with[br]

0:28:15.070,0:28:18.960
The compilers that we have[br]support for is X Code on the Macintosh.

0:28:18.960,0:28:22.040
xcode is apples free developer tools so

0:28:22.060,0:28:25.050
Anybody who has Mac OS 10 can freely[br]download that, and install our libraries.

0:28:25.050,0:28:29.000
We're using Microsoft's[br]Visual Studio Version 2005 on Windows,

0:28:29.000,0:28:32.000
we have an arrangement with Microsoft[br]where they have distributed the software

0:28:32.000,0:28:35.930
free of charge to students, so if you would[br]like to install that on your own Windows computer,

0:28:36.000,0:28:38.000
we'll give you some handouts on Friday that tell you

0:28:38.000,0:28:43.510
what to do to get the compiler[br]and get it installed on your systems.

0:28:43.570,0:28:48.020
Our cluster computers in the dorms[br]and the libraries and

0:28:48.050,0:28:53.340
the lair both operating systems have both[br]the compilers and libraries installed,

0:28:53.600,0:28:57.000
so if you work in a cluster,[br]you don't have to do anything special.

0:28:57.000,0:29:04.000
You just walk up and it's got the[br]stuff ready to go.

0:29:07.000,0:29:11.000
I'm a Mac person. I've been a Mac[br]person forever.

0:29:11.000,0:29:13.000
I can't get over the fact that you go to[br]the start menu to shut the machine down.

0:29:13.000,0:29:17.000
That makes Windows impossible for me to use.

0:29:19.000,0:29:24.970
I would say campus wide, there are more[br]Windows machines than Macs on campus,

0:29:25.010,0:29:29.000
So if you want to take a popular vote,[br]You could do that.

0:29:29.000,0:29:33.980
If you want to be on the side of the Mac bigot,[br]you can come and be with me in X Code.

0:29:44.790,0:29:49.000
I've got ten minutes to tell you a little[br]bit about C++.

0:29:49.000,0:29:54.040
That is the next journey that we're[br]going to go on together.

0:29:54.040,0:29:57.000
The first question is:[br]Why are we doing this to you?

0:29:57.000,0:30:02.000
I just got comfortable with Java and now[br]you're telling me to throw away my Java[br]and start over.

0:30:02.850,0:30:07.880
Let's generate a little bit of love for C++.

0:30:08.000,0:30:10.990
The advantages of early multilingualism.

0:30:10.990,0:30:14.000
- I have two small children at home[br]that are two and four,

0:30:14.000,0:30:18.000
and I read a lot about bilingualism.

0:30:19.000,0:30:22.000
It's very clear that for natural[br]languages, when you're

0:30:22.000,0:30:25.000
acquiring a language at those[br]young ages that that is the

0:30:25.000,0:30:27.840
best time to introduce a second[br]or third language.

0:30:27.970,0:30:30.920
Where you are building the[br]pathways and the neurons.

0:30:32.000,0:30:35.000
It's been looked at in terms of programming[br]languages as well,

0:30:35.000,0:30:38.000
that when you are learning a programming[br]language, there are certain kind

0:30:38.000,0:30:41.000
of ruts your mind gets into about[br]the way a language is

0:30:41.000,0:30:45.000
that is based on your early experiences.[br]

0:30:45.000,0:30:48.940
If you spend a very long time working [br]only in one language, those ruts get deeper,

0:30:49.000,0:30:52.000
and you have a certain way of thinking.[br]You're a little bit stuck in that paradigm and its approach.

0:30:52.000,0:30:55.680
What's easy to do in that language,[br]what's hard to do in that language

0:30:55.830,0:30:59.980
tends to make a stronger impression on[br]you in a way that makes it harder as you

0:31:00.000,0:31:04.000
grow and explore the languages to kind of get[br]out of those ruts and shake yourself out of it.

0:31:04.000,0:31:07.930
There's been some pretty good evidence[br]that somewhere between one

0:31:08.000,0:31:10.960
and two is a good time to think[br]about branching out

0:31:10.960,0:31:14.000
and starting to think about different [br]ways of doing stuff and seeing some

0:31:14.000,0:31:20.230
different syntax and some different ideas[br]to help build in the flexibility from[br]

0:31:20.230,0:31:26.450
an early age in your career to buy you[br]some strength later.

0:31:26.520,0:31:31.000
That's part of what we're doing.[br]Another part of it is actually that a lot of our upper division

0:31:31.000,0:31:36.010
courses rely on a knowledge of[br]C and C++, that family of languages,

0:31:36.010,0:31:39.000
and that the longer we postpone it,[br]the more painful it becomes.

0:31:39.000,0:31:43.950
In the later courses where you're learning[br]about compilers or graphics or networking,

0:31:44.000,0:31:48.000
they don't have the time in those classes to stop and teach you C or C++.

0:31:48.000,0:31:50.930
They need you to know C++ to get the work done.

0:31:51.000,0:31:54.940
Moving the foundation into a programming class

0:31:54.940,0:31:57.000
seems to make the most sense in the context of our curriculum.

0:31:57.000,0:32:00.000
We do switch you over here.

0:32:00.000,0:32:04.000
The good news is that it's not as big a change as it might sound at first glance.

0:32:04.000,0:32:07.000
Java is actually highly derivative of C++ for a start.

0:32:07.000,0:32:10.000
They're kind of cousins in the scheme of language design.

0:32:10.000,0:32:12.000


0:32:12.000,0:32:14.000
They have a lot of syntax.

0:32:14.000,0:32:18.110
How much C++ do you need to know to start?[br]The answer is zero.

0:32:18.110,0:32:21.000
You don't even need to know what the word means.

0:32:21.000,0:32:22.000
In fact,

0:32:22.000,0:32:25.000
you actually probably know a surprising[br]amount about C++ just by virtue of what

0:32:25.000,0:32:28.000
you already know just translated a little bit.

0:32:28.000,0:32:32.000
Things like the four loop of Java or the way you declare variables or

0:32:32.000,0:32:35.000
the way parameters are passed into a function

0:32:35.000,0:32:39.000
is exhibited in Java in very much the same way it is in C++.

0:32:39.000,0:32:42.000
There are a bunch of things you already know and you don't even realize.

0:32:42.000,0:32:45.470
It is not assumed that you know C or C++.[br]

0:32:45.590,0:32:49.000
If you happen to already know those things,[br]you're ahead of the game.

0:32:50.080,0:32:52.000
If you have not,

0:32:52.000,0:32:54.000
then not to worry.

0:32:54.000,0:32:57.000
How much C++ are you going to learn?

0:32:58.000,0:33:00.000
We will spend the first

0:33:00.000,0:33:02.000
three or four lectures

0:33:02.000,0:33:05.000
just talking about how things get expressed differently in C++

0:33:05.000,0:33:07.000
and mostly talking about

0:33:07.000,0:33:12.000
the differences in the libraries.[br]The syntax itself is quite similar.

0:33:12.000,0:33:15.000
Some of the more extensive changes have to do with how the C++

0:33:15.000,0:33:17.810
string is operated on versus the Java string.

0:33:17.810,0:33:20.000
How you do file input and output reading

0:33:20.000,0:33:23.000
in C++ is a little bit different than the way it's done in Java.

0:33:23.000,0:33:26.000
We'll spend some time saying here are some things you know how to express in one language.

0:33:26.000,0:33:29.000
We're going to teach you how to express them in another language.

0:33:29.000,0:33:31.000
It's just mapping from your previous vocabulary onto a new one.

0:33:32.000,0:33:35.000
Along the way, we will actually introduce some of the C++

0:33:35.000,0:33:38.000
features that we need to support our pedagogical goals.

0:33:38.000,0:33:42.000
We'll be talking about how classes get designed in C++.[br]We'll see how to use classes.

0:33:44.000,0:33:45.000
those classes, We'll see how to define

0:33:45.000,0:33:49.000
and we'll look at things like templates, which is the C++

0:33:49.000,0:33:52.000
construct for doing generics that you seen in Java - how you can build

0:33:52.000,0:33:56.000
containers that are type unspecific and things like that. We

0:33:56.000,0:34:01.000
will learn a little bit of some of the fancier features of C++ like

0:34:01.000,0:34:02.000
the pass by reference parameter,

0:34:02.000,0:34:05.000
but there's actually a very large amount of C++ that's just off the

0:34:05.000,0:34:07.000
table for us.

0:34:07.000,0:34:11.000
We will not make extensive use of the standard template library or

0:34:11.000,0:34:13.000
the

0:34:13.000,0:34:17.000
fancier features of 'static' and 'const' and a bunch of key words that

0:34:17.000,0:34:20.000
mean nothing to you and should mean nothing to you.

0:34:20.000,0:34:23.000
You will learn enough to have reading familiarity with

0:34:23.000,0:34:26.000
C++ and to be able to express yourself quite well in the subset we're using, but

0:34:26.000,0:34:29.000
it is a subset of C++ that you're being exposed

0:34:32.000,0:34:35.000
to.

0:34:35.000,0:34:39.000
If you find yourself really wanting to

0:34:39.000,0:34:42.000
master C++,

0:34:46.000,0:34:48.000
we are offering

0:34:48.000,0:34:52.000
CS106L. CS106L is a lab companion course that is

0:34:52.000,0:34:55.000
open to students enrolled in 106B or 106X.

0:34:55.000,0:34:57.000
It meets twice a week.

0:34:57.000,0:34:59.000
It's actually on Monday and Wednesday late afternoon.

0:34:59.000,0:35:02.000
It's 4:15 in Hewlett

0:35:02.000,0:35:04.000
103. It's being taught by a veteran section leader

0:35:04.000,0:35:09.000
who is very well versed in C++ and who of his own

0:35:09.000,0:35:13.000
volition volunteered and created this course because

0:35:13.000,0:35:16.000
he himself was a little frustrated as a prior 106 student

0:35:16.000,0:35:19.000
in wanting to get at some of those C++ things that weren't

0:35:19.000,0:35:20.000
fitting with our goals.

0:35:20.000,0:35:23.000
It is a place where you can

0:35:23.000,0:35:26.000
get more exposure to standard C++, do some exercises that help

0:35:26.000,0:35:29.000
you to test out those things and see how those things are expressed and get another

0:35:29.000,0:35:32.000
unit. It's a pass/fail lab course.

0:35:32.000,0:35:35.000
You can also just attend or grab the materials if you just want to look at

0:35:35.000,0:35:35.000
them.

0:35:35.000,0:35:38.000
It's a great way to

0:35:41.000,0:35:43.000
broaden that knowledge of C++ beyond what's

0:35:43.000,0:35:48.000
useful for us in terms of our goals. I'm going

0:35:48.000,0:35:53.000
to ask you some questions, because I don't get to do all the talking.

0:35:53.000,0:35:56.000
How much C++ do you need to know? Some of you may know nothing about it,

0:35:56.000,0:35:58.000
and that is perfectly fine. Some of you probably know something about it or at least

0:35:58.000,0:36:02.000
have heard something about it. I'm going to have you guys tell me

0:36:02.000,0:36:04.000
what it

0:36:05.000,0:36:09.000
is that people tell you about C++ that

0:36:09.000,0:36:13.000
makes you either excited to learn it or frightened to learn it or

0:36:13.000,0:36:15.000
interested in how it works. It's

0:36:15.000,0:36:17.000
what Java is based off of. It is what Java is

0:36:17.000,0:36:20.000
based

0:36:20.000,0:36:24.000
off of. That should be a little reassuring

0:36:24.000,0:36:28.000
that there is a syntax there that got adopted with some minor

0:36:28.000,0:36:31.000
changes. It should feel

0:36:31.000,0:36:34.000
more familiar than different when you look at it.

0:36:34.000,0:36:37.000
It was very strongly influenced by a generation of

0:36:37.000,0:36:39.000
programmers who C++ was their native language who designed the

0:36:39.000,0:36:42.000
Java language. That's a good thing to know. What else do you know

0:36:42.000,0:36:47.000
about C++?

0:36:47.000,0:36:49.000
It's extended

0:36:50.000,0:36:53.000
C. Yes. It's extended C. Here's how it fits in the spectrum.

0:36:53.000,0:36:56.000
C is kind of a 1970s creation. C++ is a

0:36:56.000,0:36:58.000
decade later.

0:36:58.000,0:37:01.000
C is the language which it is based on. It is an extended C. It's

0:37:01.000,0:37:05.000
called a superset. Everything that compiles and works in C

0:37:05.000,0:37:07.000
still exists in C++, but then they added a bunch of features.

0:37:07.000,0:37:10.000
Not only did they add a bunch of features but they tried to fix some of the things

0:37:10.000,0:37:13.000
about C++ by replacing existing things. For example, there's some

0:37:13.000,0:37:17.000
string handling in C that's kind of very primitive. They added a string

0:37:17.000,0:37:18.000
object

0:37:18.000,0:37:22.000
with much cleaner handling and safer semantics into the C++, but they kind of

0:37:22.000,0:37:23.000
left the old one around.

0:37:23.000,0:37:26.000
Some parts of C++ feel a little strange

0:37:26.000,0:37:32.000
because of this history to it - the legacy of incorporating everything C was plus the stuff

0:37:32.000,0:37:35.000
means at times there's a little bit of weirdness there. It also means

0:37:35.000,0:37:39.000
that the language, as a result, is very large.

0:37:40.000,0:37:44.000
C's

0:37:44.000,0:37:47.000
type safety

0:37:47.000,0:37:52.000
and runtime features were extended by what

0:37:52.000,0:37:56.000
got

0:37:56.000,0:38:00.000
added in C++. A friend of mine told me that [inaudible]. That's a

0:38:07.000,0:38:08.000
good thing

0:38:08.000,0:38:09.000
to know.

0:38:09.000,0:38:13.000
C++ might be a little bit more dangerous than Java.

0:38:13.000,0:38:17.000
That is true. Java is very

0:38:17.000,0:38:21.000
concerned with

0:38:21.000,0:38:25.000
safety, in particular since Java was designed for web

0:38:25.000,0:38:27.000
delivery of content. It was very important that the program have

0:38:27.000,0:38:29.000
very constrained

0:38:29.000,0:38:31.000
features on what it can and can't do,

0:38:31.000,0:38:35.000
and so as a result, Java tends to be very parental. When you

0:38:35.000,0:38:38.000
forget to initialize a variable or forget to

0:38:38.000,0:38:39.000
return from a function,

0:38:39.000,0:38:41.000
Java's

0:38:41.000,0:38:45.000
very aggressive about saying hey, you've got to fix this. C++ is a little

0:38:46.000,0:38:47.000
less

0:38:47.000,0:38:51.000
parental. Here's the overly protective mom, helicopter mom,

0:38:51.000,0:38:54.000
the ones who stand. That's Java. Java's making sure - oh, are you okay,

0:38:54.000,0:38:57.000
sweetie? Let me stand here

0:38:57.000,0:39:01.000
in case you fall. C++ is crack mom. She's like yeah, I'm over

0:39:01.000,0:39:05.000
here with my friends. Don't play

0:39:05.000,0:39:06.000
with

0:39:06.000,0:39:08.000
the kitchen knives.

0:39:08.000,0:39:11.000
It's a professional's tool,

0:39:11.000,0:39:13.000
and professionals don't want to feel encumbered. There are certain things they want

0:39:13.000,0:39:16.000
to do that require some of this

0:39:16.000,0:39:19.000
low-level access, and safety usually comes at a cost.

0:39:19.000,0:39:23.000
Any sort of feature where the language is double-checking for you is taking time and

0:39:23.000,0:39:26.000
efficiency. There's a cost associated with that. Every time you want

0:39:26.000,0:39:28.000
to get something out of an array,

0:39:28.000,0:39:30.000
it's checked to make sure that that number was

0:39:30.000,0:39:34.000
not off either end. Every array access costs you a little bit more.

0:39:34.000,0:39:35.000
C++ says

0:39:35.000,0:39:38.000
I'm not going to charge everybody that penalty. If you actually have the bad sense

0:39:38.000,0:39:43.000
to write a program that does those things, you deserve to be punished.

0:39:43.000,0:39:47.000
As a result, you will at some

0:39:47.000,0:39:49.000
point in this quarter get to experience some of that firsthand. Some of

0:39:49.000,0:39:53.000
it is a growth experience. Some

0:39:53.000,0:39:56.000
of it can be frustrating. It is part of what

0:39:56.000,0:39:58.000
professional tools often look like. They are making these tradeoffs

0:39:58.000,0:40:01.000
of efficiency over safety that

0:40:01.000,0:40:04.000
put more of the work back on you as the programmer to be a little more attentive on

0:40:04.000,0:40:05.000
those things.

0:40:05.000,0:40:09.000
You can write programs that crash in very spectacular ways

0:40:09.000,0:40:14.000
much more interesting and varied and dangerous than the kind of things you can do

0:40:18.000,0:40:21.000
in Java. Good to know. You want to

0:40:21.000,0:40:29.000
use

0:40:29.000,0:40:29.000
pointers.

0:40:29.000,0:40:31.000
You're going to get to use pointers.

0:40:31.000,0:40:35.000
Pointers are really neat, and they're also very challenging. Pointers are these

0:40:35.000,0:40:37.000
ways of building these very flexible and amazing

0:40:37.000,0:40:40.000
data structures - the kind of things that we're going to try to build. At some

0:40:40.000,0:40:43.000
point, they are going to be the only way to achieve those things well, so building

0:40:43.000,0:40:46.000
these things called trees, graphs and lists rely on understanding

0:40:46.000,0:40:49.000
a mastery of the pointer type. The pointer type is complicated, and it's part of

0:40:49.000,0:40:51.000
that danger thing, which is

0:40:51.000,0:40:53.000
having access to

0:40:53.000,0:40:57.000
rearranging memory by virtue of addresses opens up a lot of

0:40:57.000,0:40:59.000
opportunity for there to be mistakes.

0:40:59.000,0:41:02.000
Mistakes can be made in the passive voice

0:41:02.000,0:41:06.000
that have consequences. You'll get to experience firsthand what that's like.

0:41:06.000,0:41:09.000
There's joy in it, because getting it right is awesome, and there are things that you can

0:41:09.000,0:41:12.000
achieve that are really extraordinary with pointers, but

0:41:12.000,0:41:13.000
when it's not working,

0:41:13.000,0:41:17.000
it can

0:41:17.000,0:41:18.000
be frustrating. You're getting a

0:41:18.000,0:41:22.000
little

0:41:22.000,0:41:25.000
bit of both. It turns out C++ does not have a graphics system built

0:41:25.000,0:41:26.000
into it.

0:41:26.000,0:41:29.000
Java is actually distinguished from previous

0:41:29.000,0:41:32.000
languages. Java tries to solve all problems. Traditionally, a

0:41:32.000,0:41:33.000
programming language tends to have a set

0:41:33.000,0:41:34.000
of libraries that have

0:41:34.000,0:41:38.000
facilities for data management, reading and writing files and sometimes some

0:41:38.000,0:41:42.000
networking, but they don't tend to actually solve application layer problems. That

0:41:42.000,0:41:46.000
tended to be a different piece of technology. The Mac

0:41:46.000,0:41:49.000
OS might offer a graphics library that was written in C++, but C++

0:41:49.000,0:41:50.000
the language

0:41:50.000,0:41:53.000
didn't have a windowing system or graphics system.

0:41:53.000,0:41:55.000
C++ does not have those features

0:41:55.000,0:41:56.000
itself,

0:41:56.000,0:41:58.000
so any C++ compiler

0:41:58.000,0:42:02.000
you get comes with these basic things about handling files and managing these types of

0:42:02.000,0:42:05.000
data structures, but it does not come a priori with a bunch of graphics routines.

0:42:05.000,0:42:07.000
That said,

0:42:07.000,0:42:09.000
Windows and Mac and Linux and all these things have graphics routines that are

0:42:09.000,0:42:12.000
written in C++, but they're all different. To say what are they

0:42:12.000,0:42:13.000
like

0:42:13.000,0:42:15.000
relative to Java? They're all different relative

0:42:15.000,0:42:16.000
to Java. It's not standardized.

0:42:18.000,0:42:21.000
There's a wide variety of them out there, and

0:42:21.000,0:42:24.000
they tend to have a lot of very impressive and different solved

0:42:24.000,0:42:27.000
problems, because C++ has a longer history than Java that a lot

0:42:27.000,0:42:30.000
of problems have been solved in C++ that are available to you,

0:42:30.000,0:42:32.000
too. There's a lot of existing code

0:42:32.000,0:42:36.000
other than what you might think is standard.

0:42:38.000,0:42:42.000
I

0:42:42.000,0:42:43.000
will

0:42:43.000,0:42:47.000
see you on Friday, and we'll be seeing some C++. If you have

0:42:47.000,0:42:58.000
questions about your situation, come and talk to me now.