>> Stanford University.

>> Alright, so welcome to Stanford CS193p,

fall of 2013-14 academic year.

This is our very first lecture and we are going

to be covering developing applications

for iOS, so specifically iOS7.

Today's lecture kind of has a first part and a second part.

The first part is a little bit of logistics.

The second part is I'm going to dive right

into the course material because there's a lot to cover and so,

we need to start covering it.

[Pause] So, what will I learn in this course?

I think you know what you're going to learn in this course.

You're going to learn how to build cool apps, okay?

iOS is a really cool platform for building apps,

you probably already know that.

The apps look cool, they've got animation.

What's really cool is they're in your pockets

so you can whip them out and show them to your friends.

You don't have to send them to a website or go get a computer.

It's also really easy to develop really powerful apps

in a really short amount of time, as you're going to find.

This course is only 10 weeks long,

and while this is Stanford, I know, you're all really,

really good programmers and all that, it still,

10 weeks is not a lot of time, so when we get to the end,

you're going to see that it's a very leveraged platform

for building things.

And, you know, the community is quite vibrant,

being able to distribute your apps via the app store

and not have to put them in a box and put them on a shelf

in a store, is really a big, big difference when it comes

to marketing a product.

Okay? And you'll, you'll see that.

The second thing you're going to learn

in this course though is real-world application,

a lot of the computer science things you're learning

in other classes.

Okay? So, we're going to be doing networking,

we're going to do multithreaded,

we're going to be doing all kinds of graphics,

we're going to be doing animation,

we're going to do object-oriented databases,

we're going to do all that stuff for real, okay?

You're going to see what it looks

like to apply all those computer science concepts, especially how

to combine them into a real-world platform,

where you're making real apps, okay?

And quite a few, many dozens

of my former students have shipped their apps

on the app store and you may well too.

Okay? So this is really, this is a good course to kind of combine

or synthesize all of the things you've learned in a lot

of your other computer science classes and touch it

up against the real world.

Okay? The prerequisites for this class are super duper important,

okay?

This, it's just key to make sure you have these prerequisites

and really think long and hard, if you don't, whether you want

to give this class ago.

CS 106 A&B or, or CS16x are absolutely required, okay?

If you don't have that or equivalent, definitely,

don't even think about it.

The second requirement I've added this quarter,

based on experience, is CS107 or CS108, which is great,

by the way, if you're taking CS108,

you'll really be ready for this class.

Or even CS110, and part

of the reason I'm requiring these extra classes is just

so you're farther along the programming experience curve

because this class is a lot of programming, and so for those

of you who are used to a lot of programming,

you, you're used to it.

But for those of you who aren't it's kind of like, whoa,

do a lot of programming here.

It's going to be a little unbalancing.

So, that's why I've required all those.

Now if you've done a summer internship

of you've done some programming or something like that,

that's definitely a substitute for CS107, 108, or 110, right?

Or if you've done some other CS class that's even more advanced

than these, that's fine too.

You've just got to understand that this class is, you know,

a programming class, there's a lot of programming.

And most importantly, you got to really be comfortable

with object-oriented programming.

So I put a bunch of terms up here, like message

and instance variable and superclass and subclass,

if you don't know these terms like the back of your hand,

it's going to be hard for you to get this class,

because I'm going to be throwing those terms

out left, right, and center.

iOS7 is completely object-oriented.

Okay, the whole structure,

the design of the thing, is object-oriented.

So, you just got to know that, and if you don't know that,

you definitely want to go get that first.

Okay? Take CS106a&b equivalent first,

and then get a little more programming experience

and then you're good to go.

Okay? We're going, you're going to be writing apps in this class

with dozens of classes that you're going to write

by the fifth, sixth week so, you know,

if the biggest app you've ever written is got 3, or 4,

or 5 classes in it, oh, this is going to be a step up.

Okay? The assignments, we've got this weekly assignments

for the first six or seven weeks,

and then you've got a final project at the end.

All of the homework assignments have detailed write-up

of the required task and what we're evaluating you on.

And they also have hints in there, because I'm not trying

to make the homework assignments be really, really hard,

and all the homework assignments also directly are re [pause],

they're basically reinforcing what has been taught in lecture

in that week, they're not a bunch

of random new stuff to learn.

I'm a big believer in a teaching methodology, which is I'm going

to tell you about a concept, via slides, and then I'm going

to show you it by demoing it to you,

actually writing an application that does, then I'm going

to ask you to do it on the homework.

So that's three times you're going

to see every single thing pretty much in this class.

By the end of that, you're going to know how to do it.

Okay? And you're going to feel confident

and experienced to do it.

So the homework is all about that.

It's about just doing what you saw me do in class and talk

about in class and apply it.

Alright. Now I'm going to really briefly go over what's in iOS,

I think most of you know what's in iOS,

hopefully you've all seen an iOS device or you have one

in your pocket, I bet 90 percent of you do in this room,

but I'm going to try and summarize it,

this is really hard to do because I'm going to try

and do it in four minutes or less, or five minutes,

and it's so big that, I mean, I could have two lectures

where I just talk about all the different things

and just summarize them.

So, this is going to try and group them into some sort

of sensible groups so you have an idea of what's there

from a development standpoint, then when we go off

and start doing it all then you'll start realizing whoa,

and once you learn how to look in the documentation you'll see,

oh, look at all that stuff in there, and you'll figure it out.

So this is just a high-level overview.

So, I, I've used this division into these four, kind of groups.

Core OS, which is the stuff that's close to the hardware.

Core services, which is an object-oriented on top of that,

that kind of makes it

so you always are programming an object-oriented layer.

Media, because these devices are basically iPods with a phone

in them or with a big screen on them,

but media is really important to these devices,

and then finally Cocoa Touch, which is the UI layer.

Okay? Of buttons and all the switches, things like that.

So let's talk about what's in each of those layers, kind of,

little skimming the surface of what's in those layers.

At the Core OS layer, near the hardware, is a Unix kernel.

Okay? This is a Unix operating system on this device.

And BFD-based mock, and so you get everything you get

with Unix.

You're getting sockets and you're getting file system,

permissions, all that stuff, plus you're getting a bunch

of other stuff that's kind of specific to a mobile device

like this, like power management, and key chain access

to kind of manage the security of things.

Bonjour, which is this kind of network,

finding other things on the network.

So it's got all that stuff,

it's a very powerful underlying operating system.

But all of that API or most of it is in C,

and we want to be programming kind

of purely object-oriented layer.

So we're going to be mostly operating when we're talking,

touching those things at the Core surfaces layer.

So this layer has things like language, things that,

that kind of make the language more powerful, like arrays

and dictionaries, and strings and things like that,

plus it has object-oriented ways to access the file system,

it has object-oriented ways to find out the GPS location

of your device, for example.

It has ways to do multithreading.

All this stuff what you want to be able to do, but you want

to stay in an object-oriented kind of mindset

as you're doing them all.

There's a huge layer, foundational layer there

at Core services for doing that.

At the media layer, don't sleep on this layer,

really important layer, you've got video here,

you've got video editing, you got images, of course,

that it can display, it's incredibly powerful audio

for doing 3D audio, if you have games,

you can make the Thai fighters feel

like they're ripping by you and stuff.

All that stuff is in here.

This is part of, the part of iOS

that really I can't cover in a lot of depth.

I'm just going to try and let you know that it's there

and you're going to dive down depending on what kind

of applications, later in your life, you want to build.

But there's an enormous amount there.

This is a fundamentally, a multimedia device, obviously,

and then, Cocoa Touch is where we're going

to spend most of our time.

This is where you are going to be building buttons and sliders

and text fields, talking to each other, and animation happening,

things sliding in and out, and, you know,

fading out and fading in.

If you want to get the, a picture from the camera

from the user, you can do that.

Things like localization so that you're app can run

in many countries in the world and up your sales by doing that.

A whole map kit for doing all the 3D maps

that you've probably seen in iOS7 and all

that stuff is all in there.

And, there's even a view

in there that's an entire web browser in a little rectangle

that you can just plop right into your app.

So these are really high-level objects, and we're going

to really be diving into this layer, alright?

So this is really the primary.

And it's called Cocoa Touch because the API

in here was originally developed for Mac OS X,

and it was called Cocoa, and of course then when they went

to iOS, they adapted, and a lot of API is shared

between the two platforms, and, in fact,

if you develop an iOS app and then you say someday, oh,