ProgrammingMethodology-Lecture01.pdf

Programming Methodology-Lecture01

Instructor (Mehran Sahami) :Alrighty. If you could have a seat, please, we need to get

started. There are still a bunch of people coming in the back. Come on down and try to

find a seat somewhere. If you can't find a seat, sit in the aisle as long as you're not a fire

marshal. Anyone here a fire marshal? Good. We're fine. Come on in and sit in the aisles.

So welcome to CS106A. If you don't think you should be in CS106A, you think you

should be somewhere different, now is probably a good time to go, not that I would

discourage anyone from taking this class. I think we'll have a lovely time in here. But this

class is CS106A or E70A, so if you're, like, "Wait. I thought I was in E70A," you're fine.

They're the same class; it's the same thing. No worries, okay?

There's four handouts. They're in the back. If you haven't already gotten the handouts

because you came in and you sat down, don't worry. You can pick them up on the way

out. They're the same handouts. They'll still be there.

So just a quick introduction. That's what the first four handouts actually give you. They

give you a little bit of an introduction to the class, what we're gonna cover, some logistics

for the class and some other stuff. I'm gonna go over all that today so we can sort of get a

good idea for where we're at, okay?

So just a quick show of hands before we get into a bunch of things in the class. This is

kind of an intro-programming course; well, it is. I shouldn't say it's kind of an intro-

programming course. It is an intro-programming course. And it's always good to get an

idea as to how much familiarity you may have beforehand, okay? So just quick show of

hands. How many people can recognize a computer that's on? Good, good. That's the

prerequisite for this class.

So if you're worried about how much previous experience you've had or your friend who,

like, worked their way through high school by programming for Google or whatever,

don't worry about it because all you need to know in here is basically either how to turn a

computer on or to recognize a computer that's on if you were to walk up to it and it were

already to be on, all right?

So but a little bit more seriously, how many people have actually used a computer for

anything? All right. I would expect most of you.

So now, we begin to bump it up a notch. How many people have used it for word

processing? Okay. Most folks.

How many people have done web browsing? Yeah, I won't ask you what you look at, all

right? It's just I don't wanna know.

How many people have actually created a web page? Okay. Fair number.

How many people have done any kind of programming before? Fair number. All right.

How about how many folks have done actually programmed in Java before? All right. A

few folks.

How about another language, C, C++, BASIC, anyone program in BASIC? Yeah, oh, I

love — that was the first language I learned, and it was kind of like the warm and fuzzy,

and I felt good. There was actually people who argued that if you learn BASIC as your

first language, you're brain damaged, then you're just beyond help. But if that's the case,

we're all in the boat together because I'm probably brain damaged as well. The truth is I

probably am, but that's a whole different story.

All right. So one thing you should know kind of up front is actually this course is gonna

be provided eventually somewhere down the line as part of Stanford School of

Engineering Free Course Initiative, which means not only are we recording this course to

broadcast to a bunch of companies and industry who are watching this course, but we're

eventually gonna provide it free to the world.

So how does that impact your life? And on the average day, it doesn't at all. The only

way it does impact your life is just so you should know, the lawyers told me to tell you

that your voice, should you ask a question, may actually be recorded as part of the video.

As a result, your voice may end up going out to thousands of people or millions of people

in the world. If you have an issue with that, come talk to me. If you don't, everything is

just fine, all right?

Don't worry. We're not gonna put your picture up or anything like that. You might wanna

be on the video, like, "Hey, ma, I'm on TV." We decided that we're just gonna not show

anyone actually on the video, but your voice may actually get recorded, okay?

Now, along those lines, you may also notice there are some microphones in the room. So

when you wanna ask a question, please make sure to use the microphone because that's

not only good for people in here to be able to hear your question, it's also good for all the

folks that this is getting broadcast to because not only are we gonna broadcast to the

world, but there's actually some folks who are sort of watching this live now in various

companies in Silicon Valley.

So it's real important that you actually use the microphone, so just remember that. And

every once in a while, I might get on your case and be, like, "Please use the microphone."

I'm not trying to be argumentative or anything. I just wanna make sure we pick up all the

audio, all right?

So with that said, a little bit of an introduction. That's kind of a way of background. I

didn't give you any sort of introduction. So just to introduce myself, my name's Mehran

Sahami. I'm the professor for the class. Don't call my Professor Sahami, way too formal.

Don't call me Mr. Sahami. That, I think of my dad. And don't call me Mrs. Sahami, or

we're gonna have issues, all right? So just call me Mehran. We'll get along. It's just fine,

all right? It's to keep things a little bit more informal, but that way it's a little bit easier to

discuss stuff as you go along.

There is also a head TA for the class, Ben Newman, who's standing up there. Get to know

Ben. He has all the real power in this class. I'm just kind of the monkey that gets up here

and gives the lectures. But Ben really is the one who's got all the power.

Along with the head TA for the class, we have a large section leading staff. So the section

leaders here, could you stand up if you're here? They're kind of all over the place, some

over here, some over there, and some over there. As you can see, there's a pretty large

number of folks. And this isn't even all of them. We sort of have more — we just can't

stuff them all into the room — who are section leaders for the class, and these folks are

all here to make sure that everyone in this class has as good an experience as possible

when we're sort of going through the class.

And the best way to reach all of us is email. So on Handout No. 1, you get my email and

Ben's email. We'll tell you how to sign up for section. That's how you'll meet your section

leader and get your section leader's email. That will all be coming soon. But email really

is kind of a happy form of communication to get a hold of us, okay?

So with that said, I wanna tell you a little bit about this class and kind of what we're

gonna do in here and what you should expect and make sure that you don't feel scared off

by this class, okay? Because it really is meant to sort of be an interesting time.

But one question that comes up is why is this class called Programming Methodology,

right? Why don't we just call this class, like, Programming with Java? And the real reason

for that is that programming methodology is about good software engineering principles.

It's about something that's much larger than just programming.

So some people, like, they'll go and get a book somewhere and they'll think they learned

how to program by just reading the book. And they're, like, "Oh, I know how to program.

Isn't that great?" And it's, like, yeah, you might know the mechanics of the language, but

the mechanics of the language are nothing compared to understanding the software

engineering principles that go into actually developing a software system.

And that's what you're gonna learn about in this class. You're gonna learn a lot of those

principles. But in order to be able to use those principles and apply them, you also need

to have the language to program in, and that language that we're gonna use in this class is

Java.

So the way I like to think about it and the way I tell a lot of people is writing a good

program or learning how to program is like learning to be a good essay writer. And

you're, like, "Oh, but part of the reason I'm taking this class, Mehran, is that I don't like

writing essays." That's fine. It's okay. Trust me. I didn't like writing essays either.

But the whole point is that when you write an essay, it's not a formulated kind of thing.

You're, like, "Well, what about five-paragraph essays?" Yeah, just block that from your

mind. That was a bad time, right? That was just, like, '70s education at work. It's not a

formulated kind of thing.

There's an art to writing an essay, right? In order to write an essay, you need to know a

language. You need to know English or German or Hindi or whatever language you

wanna use, but then you use that language to write an essay. Just knowing the language

doesn't make you a good essay writer though. Being a good essay writer makes you a

good essay writer.

So that's the same difference in programming and software engineering. Knowing the

language, in order to be a good programmer, like a good essayist, you need to know a

language to write your programs in, whether that be Java or C or C++ or whatever. Here

we're gonna use Java.

But just knowing the language doesn't make you a good software engineer and doesn't

make you understand what the principles are of writing good software, which is what

you're also gonna get in this class in addition to the language, and that's kind of a key

thing to stress.

So if you're sort of worried, if you were kind of looking around and you saw a bunch of

people raising their hands when I asked, "Do you have any previous programming

experience?" and some folks raised their hands, and you got a little worried and you're

like, "Oh, am I gonna be in some sense at a disadvantage because I haven't done any

programming before?" The answer, plain and simple, is no, okay? You're gonna learn

everything you need to learn from the first principle because as a matter of fact, in some

cases you might be in slightly better shape. That's not necessarily to say that that's the

way it will be.

But how many people are Star Wars fans? Just wondering. Anyone? I'm talking about the

old-school, original, like, three movies. Those were so good, and we're not — no George

R. Binks here, all right? So if you remember — and sort of I'm a big Star Wars fan, and

that's just a whole separate point. But in the second movie, Yoda actually said something

which I thought was quite profound, which is he says sometimes you have to unlearn

what you have learned.

And one of the things we actually find is that some people who are self-taught

programmers, some of them are just fine, and some of them are very good. But some of

them have picked up some really bad habits along the way, and it's like being a bad essay

writer. And to go from being a bad essay writer to a good essay writer, in some cases, can

actually be harder than from not being an essay writer to being a good essay writer

because you have to unlearn the bad habits.

So if you're worried about, "Oh, I've had no previous experience," don't worry. You're

okay, blank slate, you're just fine. And now if you're thinking, "Oh, I have some previous

experience. Do I have bad habits?" Don't worry. You'll be fine, too, okay? So it's all

gonna work out.

So the next question that kind of comes up — hopefully that helps put some of your fears

aside. Another one of the things is that we really strive to make everyone successful in

this class, okay? At some other schools, people wanna do computer science or they

wanna do an engineering major or whatever. And you come into the first day of class,

and they say, "Oh, only one third of you are actually gonna make it through this program.

And look to the person to your left and look to the person to your right, and only one of

you will make it through." And you're, like, "Oh, man, that's real nice." It's not like that

here.

As a matter of fact, we want all of you to be extremely successful in this class, which is

why we have a huge course staff, which is why over years and years we've refined how

we do a lot of the teaching in this class to make sure you have the best possible

experience and to make sure that everyone gets through.

And the important thing about that is that you're not competing against anyone except

yourself in this class. It's not like we're gonna have a curve and we're gonna say, "Oh, we

have a certain number of "F"s and a certain number of "D"s and a certain number of

"C"s." All we really have going into it is an expectation that when you get out of here,

there's a set of stuff we want you to know. And if you know that stuff well, you get an

"A." And if everyone knows that stuff well, everyone gets an "A." And I got no problems

with that. Registrar might have a problem with that, but that's okay. You don't need to

worry about that.

So you don't need to think about, oh, is someone else doing better than you or whatever.

And we'll talk about issues of collaboration in just a little bit. All you need to think about

is learning the stuff yourself as well as you possibly can, and you'll be just fine and you'll

get a good grade, okay? So that's really all we ask, which is not a trivial amount, right? It

requires you to really understand the material.

So another question that comes up is are you in the right place, right? This isn't the only

introductory programming class at Stanford. And so I wanna spend a little bit of time

making sure you actually are in the right place by going over some of the different

options.

So right now, as you know, you're in CS106A. And CS106A, we're sort of happy over

here, right? As a matter of fact, we're not only happy, we're happy and we're also a little

bit loopy, right? There is no previous programming experience required, as I mentioned,

right? All you need to know is basically if you can get to a computer and know how to

figure out that it's on, you're in good shape.

But what 106A does is it's a real rigorous class. You learn programming in here, and you

learn it in a way that makes you ready to be an engineer if you so choose to be an

engineer. That's not to say you're all gonna be engineers. I would love for all of you to be

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