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cs50

основы программирования

cs50 на русском

cs50 лекция 16

Week 8

00:00:17

welcome to harvard for the seo course

00:00:21

swifty

00:00:24

is ses fifty and we are starting the eighth

00:00:28

week and he has returned to us and we are glad to

00:00:30

welcome him to us alcohol ramon

00:00:32

galvan and our almost graduate

00:00:34

who has spent the last few

00:00:36

months since july in los angeles in

00:00:39

hollywood working on the new

00:00:41

sci-fi television series

00:00:43

Colony, the creator of which, by the way, is

00:00:46

also a Harvard graduate, sit down,

00:00:48

look forward to the premiere of the series in

00:00:51

January, don’t miss it and watch Ramona

00:00:53

in a few weeks,

00:00:54

well, the end is near, that is, we have

00:00:57

very few left of all fifty, as

00:00:59

sad as it is, only three problem books

00:01:01

Problem book number 6, which you are working with

00:01:03

now or will soon begin, is like a

00:01:05

bridge between the world of the command line in

00:01:07

which we spent most of our

00:01:09

time and the world of web programming,

00:01:12

you will come across many ideas

00:01:13

borrowed from the command

00:01:15

line system, as well as many interesting ideas that are

00:01:18

directly related to mobile

00:01:20

applications and in general technologies

00:01:21

that you guys are well

00:01:23

familiar with today thanks to your laptop phone and

00:01:25

other devices, you will

00:01:27

not have to implement a web page or a website

00:01:29

as such, but the

00:01:30

web server itself, you will need to write down the

00:01:33

rest of the web server that is currently

00:01:35

written in the essence it turns out that

00:01:37

http requests and virtual packets

00:01:39

that we talk about so much are answered

00:01:42

either with some static content,

00:01:44

such as a .

00:01:45

html or . cap or other or

00:01:48

php files in this case your web server

00:01:50

will decipher the php code and display the results

00:01:53

we have provided you with general schemes for

00:01:55

working the distribution kit 6 problem books contain

00:01:58

more than a thousand lines of code, although many of

00:02:00

them are comments and this is a very good

00:02:02

opportunity to immerse yourself in a

00:02:04

really serious project

00:02:05

every element of which we have carefully

00:02:07

thought out so that when you complete the Swifty course,

00:02:10

go out into the real world of programming

00:02:11

and want to take on some projects,

00:02:14

you feel comfortable

00:02:15

encountering source codes and open

00:02:18

projects on the Internet, immersing yourself in it all and

00:02:21

making your own amendments, problem book

00:02:23

number seven is dedicated to how make

00:02:24

your own web application using

00:02:26

dynamic input and output of data as

00:02:29

on the site and trud.com and the like, and the

00:02:31

8th problem book contains exercises in

00:02:34

another language called java script, in

00:02:37

general, the final project is just around the corner,

00:02:39

and the so-called pre-project will be necessary

00:02:41

handing in a pre-project in a week

00:02:43

according to the glossary in all aspects is

00:02:45

simply an opportunity to send a short

00:02:47

letter to your supervisor to tell

00:02:49

him or her about your thoughts, to confer, and at the

00:02:51

same time check whether you have gone too far

00:02:54

or, on the contrary, will not bother yourself, or maybe

00:02:57

you have no thoughts at all and you

00:02:59

want it discuss

00:03:01

next is the development of the project and a report

00:03:03

on the success of the sea of fifty hackathon in

00:03:05

Cambridge for Harvard and Yale students,

00:03:08

then the final implementation of the project and

00:03:11

finally the fair with fifty

00:03:13

1 here in Cambridge and 2 in New Haven,

00:03:15

details on our website but

00:03:17

really interesting with With a cool

00:03:19

head and a warm heart, immerse yourself in

00:03:21

topics tools and techniques that

00:03:23

are additional in the course program

00:03:25

but nevertheless very useful; excellent

00:03:28

building blocks for truly cool

00:03:30

projects that will go beyond

00:03:31

what was in the problem books and in

00:03:34

lectures, beware, I have a list

00:03:36

all seminars if you haven’t

00:03:38

registered yet, nothing come in and

00:03:40

register calmly and we will

00:03:42

post everything online as the day and time are

00:03:44

indicated on the website everything will be recorded and

00:03:46

posted online if you can’t

00:03:48

join on a specific day and what

00:03:50

else we have coming up is of course a hackathon with

00:03:53

fifty remember this photo from week zero

00:03:56

it was taken at about 4 am a few

00:03:58

years ago if the ses fifty fair which

00:04:00

will be held in both cities

00:04:01

well and for the future although we still have a

00:04:04

whole month left in the semester

00:04:05

but if you want to join the

00:04:07

teaching team with fifty if

00:04:09

you are you thinking about becoming an

00:04:11

assistant or curator please keep in mind

00:04:13

that we will be discussing this in more detail at

00:04:15

the end of the semester in the picture most of

00:04:17

this year's team and so

00:04:18

php I was so upset last week

00:04:21

that Alice tried to provide on with these

00:04:23

wonderful props and I didn't have time for them

00:04:25

use it, but it really

00:04:27

turned out stupid that we wasted the whole Wednesday here with a

00:04:30

shovel and a small spoon, but with this

00:04:32

metaphor I just wanted to explain

00:04:33

why we are moving from the C language to a

00:04:36

language like stoves, the same can be

00:04:38

said about any other language java python

00:04:40

ruby and others while in writing a

00:04:42

program it looks like we are taking a

00:04:45

small spoon and dripping a hole in the ground

00:04:46

sand or mud poking allows you

00:04:49

to deal with the task much faster

00:04:51

by writing much shorter

00:04:53

code art using fewer

00:04:55

tools thanks to its serious

00:04:57

functionality background for greater

00:04:59

clarity you can It would be good to dig

00:05:02

something here, well, and God bless him, another

00:05:04

metaphor about which we resorted

00:05:06

is a wrench into which you can hammer

00:05:09

a nail, although of course the more appropriate

00:05:12

tool here would be not so much the language of the

00:05:14

sex help, I seem to have ruined everything,

00:05:17

I hope Sanders is subordinated to live arcade

00:05:20

the right tool will often be

00:05:22

for me this low level language again in

00:05:24

general and

00:05:25

this is not a language that most of

00:05:27

you will or should use

00:05:29

in general a little secret I mainly

00:05:31

work in C only from September to December

00:05:33

every fall semester this is because we

00:05:36

use everything in mainly for teaching the

00:05:38

basics of programming and the basics of

00:05:40

computer science,

00:05:41

data structure, algorithms and all

00:05:44

that, but very soon you will see that

00:05:46

the syntax and ideas of the C language are perfectly

00:05:49

transferred to higher-level

00:05:50

languages such as stove concrete and pearl java in the

00:05:54

whole object, although the whole object is not quite

00:05:57

Swift yet, it’s more modern languages in

00:06:01

which many of you will write the

00:06:03

final project, although without too much

00:06:05

fuss, let's use the stove to

00:06:08

solve problems. You remember last

00:06:10

week in food and the lucky ones, we wrote an

00:06:13

elegant little program that

00:06:16

output hallow

00:06:17

then did not save the robe in the file. bake

00:06:20

spots

00:06:21

and then asked this command and why was it in

00:06:23

simple words, what does this mean, what

00:06:26

did I do, yes, in such a command, yes, there is such a

00:06:28

stove function that reads

00:06:31

and understands what is there when there is a certain

00:06:33

function from the stove, and more precisely, there is a program

00:06:35

called stove,

00:06:36

which is also an interpreter understands the

00:06:38

contents of the clap and interprets it

00:06:41

from top to bottom from left to right and do what

00:06:43

these commands say into the commands in the stove,

00:06:46

this is of course just the source code of the function

00:06:48

and variable loops and the like,

00:06:50

which we ourselves started writing, stuffed with it,

00:06:53

unlike C, which compiles the code

00:06:55

on the stove, you just write and run there is

00:06:57

no need for an intermediate step with conversion to

00:06:59

zeros and ones, we immediately run the program

00:07:02

and what is the advantage here, why are we

00:07:04

skipping a step? this is not why most

00:07:06

modern languages tend to

00:07:08

skip this step, which is a plus, well, it’s

00:07:16

intuitive, even if we have

00:07:18

written a little on the stove so far what is the advantage of the fact

00:07:20

that the cat does not compile, what do you

00:07:22

think, I can’t risk it, I just

00:07:24

scratched my head more dynamics, what do you

00:07:29

mean if there is a lot of input data, it

00:07:31

takes a lot of time every time, yes,

00:07:35

good, so you don’t have to

00:07:37

compile the program every time after the

00:07:38

new year, that’s it that's all, what's the point of

00:07:41

constantly compiling code, it's just a step that

00:07:43

needs to be done as over the

00:07:44

past weeks there have been twice as many steps

00:07:46

compared to simply running

00:07:48

the program, now it's useful to

00:07:49

see any errors and so on, but

00:07:51

it's just an extra step and one day

00:07:53

the programmer was asked The question is why

00:07:54

not start inventing languages in which there

00:07:56

will not be such an overtly mechanical

00:07:58

step, in which you can simply write code

00:08:01

and run it, well, what price did you have to

00:08:03

pay, as we saw last

00:08:05

week in a specific example of speed, the

00:08:07

speed of the interpreter is slightly

00:08:08

slow, the computer understands zeros and ones

00:08:11

quickly because that the

00:08:12

Intel or any other central processor simply

00:08:14

understands what is happening with all these

00:08:16

bits, but the interpreter

00:08:18

is a program that has to read the

00:08:20

source code of the ask that you wrote and

00:08:22

convert it, so to speak,

00:08:24

guess how it would be converted

00:08:27

into zeros and ones so it has a little

00:08:29

effect in terms of performance, this is the

00:08:31

price, let’s look at this with an example.

00:08:33

Now I’ll write a program here, files,

00:08:36

go here a

00:08:38

new file, saving it again as a fleet.

00:08:41

oven we take colleagues and then write print

00:08:43

hello will allow a rating

00:08:46

and remember I can use print they

00:08:48

need a printer now below I write oven and

00:08:51

Achilles. stoves,

00:08:53

but it looks like I interpreted what I did

00:08:57

wrong, yes, we need angle brackets

00:09:01

on top at first, it’s a little annoying, but

00:09:03

you’ll quickly get used to it. If I write code on the

00:09:06

stove, I have to tell the program to the

00:09:08

php interpreter, here’s the stove code, and

00:09:11

to top it off, I have to close the brackets, but

00:09:14

not the same but with only one question mark

00:09:17

now at the bottom, if I run the program,

00:09:19

I will get the desired result. I’m angry,

00:09:21

but let’s optimize a little like we

00:09:23

did before. It’s slightly annoying that when

00:09:25

you start you have to write estrus space holo.

00:09:28

. because before I could just write in .

00:09:30

I hear the name of the program and it was convenient, it

00:09:32

saved the user time from the stove and

00:09:35

this can be done in Thai,

00:09:37

use this hieroglyph

00:09:40

here at the top which is called Yeshe

00:09:43

path bank consists of a hash and an

00:09:45

exclamation mark for everyone and this is the path to the

00:09:47

program in a typical Linux system

00:09:49

which is called environment in warm on

00:09:51

wings of and this line, in short,

00:09:54

line number one simply says she and the

00:09:56

computer find me a stove interpreter

00:09:59

in this environment, that is, find it in your

00:10:01

memory and the good thing is that if now

00:10:05

I write at the bottom of the emotions. hear hello

00:10:09

. nail files low dabka or and permission

00:10:13

is denied you will often encounter something like this in the

00:10:15

seventh problem books if permission has not already been given,

00:10:18

it turns out I need to

00:10:20

execute this command than I could change the

00:10:22

mode and plus x hello dot php

00:10:26

I need this extra step to

00:10:28

tell my computer to make a robe.

00:10:31

php executable file

00:10:33

and now look. heard. the stove

00:10:35

starts up anymore, I don’t need to

00:10:37

designate the interpreter,

00:10:39

you can make it even more beautiful by renaming

00:10:41

this

00:10:42

temporary robe. stove just hollow

00:10:44

look boldly at the top the name of the program is

00:10:46

now just hello that is, I can

00:10:48

make it look like a program

00:10:50

even though it’s PHP or in any other language

00:10:53

just a slight optimization no

00:10:55

functional difference

00:10:56

but what’s interesting is now you can write

00:10:58

programs in any language and the user

00:11:00

does not it is necessary to know which one

00:11:02

and now let's take a look at a more

00:11:05

interesting example that I sketched out

00:11:07

in advance the program is called kao lak

00:11:08

dot php

00:11:09

it is available on the net it is quite

00:11:11

short but it is a console program and

00:11:13

it will look for me stock prices

00:11:15

about very similar to what you will meet in

00:11:17

problem book number seven, let's see

00:11:19

where oh no at the very top the brackets

00:11:21

open? oven and then I have a line

00:11:24

where I request a file called

00:11:25

functions.php, we will look at this

00:11:28

in more detail, but in general this is an analogue of the lattice in the cloud,

00:11:30

everything is when you want to include

00:11:32

another php file in the code for this there are

00:11:34

arecave designs, although the

00:11:36

renclod function is also included in it he

00:11:38

wrote the functions.php file in advance before the

00:11:40

lesson, I put it in the same directory

00:11:42

because I wanted to bracket some

00:11:44

code that we can use somewhere else,

00:11:46

in general, you can probably

00:11:48

guess what’s going on here is a little

00:11:50

different from C, but what do I have in view of

00:11:53

making sure the correct use

00:11:54

translate this into a more technical language

00:11:56

under what circumstances do I terminate

00:11:58

or exit the program before when I do

00:12:03

not have two command line arguments

00:12:05

remember that one of these arguments is or the

00:12:07

program itself

00:12:08

and the second is another word that I write

00:12:10

after the prompt, that is, like and that’s it, I’m

00:12:12

checking whether the user is executing the

00:12:14

program as intended

00:12:15

and now there’s something new compared

00:12:17

to firstly there’s a dollar sign and that the

00:12:19

dollar sign means the stove is

00:12:22

just a variable and everything is just a

00:12:24

variable and these signs are followed by its

00:12:26

name, please pay attention my the stove

00:12:27

program is missing something compared

00:12:29

to and like last week that these are

00:12:32

types yes but something else you tell me something

00:12:38

related to the functions of the main function there

00:12:41

is no main function here

00:12:43

you start writing code without worrying about the

00:12:45

absolutely conditional spent calling a

00:12:47

certain standard the function main

00:12:48

arxi is just a global variable

00:12:51

that the interpreter

00:12:53

does not provide, but then the interesting thing is

00:12:55

the search itself, the dollar sign on the left, the drain

00:12:58

is my variable on the right, obviously

00:12:59

a function that in the oven is called

00:13:01

lookup search which I pass my

00:13:03

last command line argument

00:13:05

some word in a minute we’ll see

00:13:07

how it works and finally the program

00:13:09

reports the price, gives out 1 share of so-and-so and

00:13:13

remember that in the oven there is a special

00:13:15

way when you no longer need to write a

00:13:18

dollar sign with it, but you can simply

00:13:20

indicate a variable in curly brackets and the same

00:13:22

sprinter, it is not necessary for their word when

00:13:24

you place variable in double quotes

00:13:25

like here you are using a complex technique

00:13:28

called variable interpolation

00:13:30

it simply means inserting a variable

00:13:31

here change by the way who came to us with

00:13:34

experience in programming in other languages

00:13:36

remember you cannot use

00:13:38

single quotes for these purposes with a string

00:13:40

inside

00:13:41

to interpolate variables needs

00:13:42

double quotes a otherwise you

00:13:44

will literally see those same curly braces

00:13:47

and finally let's run our

00:13:48

program I'll

00:13:49

enlarge the terminal window but I

00:13:52

'll run it inside the directory anyway ok here you go

00:13:57

source 8th coat oven pequod dot php and

00:14:01

I'm also something called [ __ ] this

00:14:04

sticker stock code google so 1 share

00:14:07

already under the new name lgd.int costs

00:14:09

717 dollars today if we launch it again, can

00:14:12

anyone tell me another stock code

00:14:14

that you want to look for Maykop

00:14:18

microsoft seems like this msft

00:14:20

53 dollars and Yahoo probably has this but

00:14:25

Facebook and so what does this

00:14:28

program seem to do this function lookup

00:14:30

has some kind of magic, let's

00:14:31

see, it looks like it's not built into the stove,

00:14:34

but is taken from spunk chance. stoves, we won’t

00:14:37

go into too much detail, but pay

00:14:38

attention to this keyword in line

00:14:40

6 of the functions.php file, because I literally

00:14:43

say function, I denote the name of my

00:14:45

functions, then denote all the arguments

00:14:47

or parameters that I want this

00:14:49

function to accept, no types, and then

00:14:51

execute and and we won’t stop

00:14:54

working now to this level, we’ll

00:14:56

get to this level in a week in problem book number

00:14:58

seven, this can now be erased,

00:15:01

I also included in today’s code a version of the

00:15:04

cvut file that does not have a

00:15:06

stove extension because it is pre-designated

00:15:09

at the very top of the program called k

00:15:11

here that same so-called bank is a

00:15:13

real crypto graphical symbol

00:15:15

that says find the stoves and run

00:15:18

it in my code so we come to

00:15:21

where we left off last time only

00:15:23

with more complex examples there are questions

00:15:25

about php or what we did here no

00:15:29

good yes inside the file html is also

00:15:33

used by she bank or you can simply

00:15:35

raise a good question in the web context

00:15:39

which we will come to shortly and the so-

00:15:41

called shaman is not used at the

00:15:44

beginning of the code because web servers

00:15:46

for example apache or microsoft

00:15:48

oh oh with the Internet informations server or

00:15:50

any other web server know that when

00:15:53

they encounter a . stoves need

00:15:56

to run an interpreter for it

00:15:57

they don’t look at the first line

00:15:59

the trick the first line is only needed

00:16:01

when we write programs with the command

00:16:03

line

00:16:04

and we won’t do this often we

00:16:07

connect our examples in this way you with

00:16:09

php

00:16:10

well let’s build a bridge between the

00:16:13

world of the command line and the network as

00:16:16

follows I will now draw something here

00:16:21

we have a web server or better yet my

00:16:24

laptop I will draw it like this and here we have the Internet like

00:16:29

this and here is the server in the building this is how the

00:16:31

Internet works here there is a

00:16:34

server

00:16:35

g a lot of light bulbs what is happening

00:16:38

between with these three elements in this

00:16:41

building, a web server is just a computer

00:16:43

on which a certain operating

00:16:45

system runs, it can be free and the patch

00:16:47

that runs aldi

00:16:49

has disappeared fifty so it can be

00:16:51

imagined as the building where go

00:16:53

and seas fifty is located, this is where all

00:16:55

your profiles are stored all your

00:16:58

own servers work here, all

00:17:00

your unique url addresses are collected here, which we

00:17:02

started talking about, which you will still

00:17:04

meet with problem books number 6, but my

00:17:06

laptop is somewhere else on the

00:17:09

Internet and when I go to my url,

00:17:11

Internet traffic goes through the server the server

00:17:13

receives an http request in the form of get index

00:17:16

dot html and responds to this web page,

00:17:18

this is the general scheme and everything up until

00:17:21

today happened only within the

00:17:22

boundaries of this building and used my

00:17:25

laptop window connected to the ID disappeared fifty that

00:17:28

is, all the programs that I launched you

00:17:30

were on this very server

00:17:32

but now let's use php

00:17:34

in a different way to write real

00:17:37

programs that will be served by a

00:17:39

web server it or let me give

00:17:41

you a few I'll give you a lot of

00:17:43

examples that will illustrate this

00:17:45

idea here is a fairly clear way to

00:17:47

describe the programming scheme in

00:17:50

reality when you're done course with fifty

00:17:53

or you will work on the final

00:17:55

project or continue your studies

00:17:57

you will begin to understand that the world especially those

00:17:59

who are accustomed to such low level languages

00:18:02

as C you will understand that there are better

00:18:04

ways to write programs there are

00:18:06

certain patterns that you can

00:18:08

use special ways of organizing

00:18:10

files anti function names in short

00:18:13

speaking the world is full of all sorts of different

00:18:16

acronyms of ways of programming it's

00:18:19

just a technique that you can

00:18:21

use one of them is called m

00:18:23

visi control view model and in

00:18:26

our case it's just a more ornate

00:18:28

way of saying how you should

00:18:30

set up a website on the stove

00:18:32

that is how you organize your

00:18:34

file and build your own logic, all this

00:18:36

makes it somewhat easier to write more

00:18:38

complex websites.

00:18:39

By the way, you will encounter this in the seventh

00:18:42

problem book, and so on the mvc diagram you will see

00:18:45

that your code can be generally

00:18:47

characterized either as a cat model

00:18:49

or as a cat controller or as presentation code to

00:18:52

put it simply, the controller is the

00:18:55

brains of your program, this is where

00:18:56

all the interesting

00:18:58

logic is implemented, everything that we have written so far in the

00:19:00

class is a kind of controller code, it

00:19:03

controls your program, your loops, your

00:19:04

conditions, your functions, variables and

00:19:06

other representations become more

00:19:08

important in programming. about

00:19:11

presentation, the view is the aesthetics of your

00:19:14

site, this is what the user sees

00:19:16

in the table html, html tags and the

00:19:19

like 10 subtle aesthetics, which is

00:19:22

not difficult to write, how

00:19:24

your site is presented, its appearance, aesthetics, and the

00:19:26

model is a kind of database, what

00:19:28

we will begin to dive into the environment juice is not so

00:19:32

controller is logic representation is

00:19:34

aesthetics and model is the place where we

00:19:36

store the actual data gossips let's

00:19:39

look at everything in more detail using the following

00:19:41

example I go to my directory of

00:19:43

today's source code it is available

00:19:45

online I

00:19:46

go to version 0 and what we see is the entire

00:19:51

let's call this version 0 web -the site of the axis with

00:19:54

fifty there is not much to look at here it is a

00:19:57

very simple web page that

00:19:59

uses some ideas honor l

00:20:02

try to guess from the examples which

00:20:04

one is another possible for this bold

00:20:06

heading of this seas fifty logo

00:20:08

at the top and which ones are still before the

00:20:11

bulleted list then there are t p o l and

00:20:14

maybe tags

00:20:15

oh he’s from logan it’s not scary if you forgot

00:20:17

there are many elements from the topic that are

00:20:19

easy to find and which you will

00:20:21

often return to and we’d better

00:20:23

focus on more interesting

00:20:24

programming tasks let’s quickly

00:20:26

look at the html if I open it to

00:20:28

look source code then we will see what is

00:20:30

happening here like this y.l. inside

00:20:34

it are two volumes and then I

00:20:37

borrowed the viorel of the real course from the

00:20:39

lectures file. oven and another

00:20:43

dynamically created page in which

00:20:46

a 2 1 week lectures 0 and 1 week let's

00:20:49

look at them look at the source code,

00:20:51

too, everything is simple

00:20:52

these files lead to two pages of wiki 0 and

00:20:57

ovens and Vicodin ovens

00:20:59

because look what happens when I

00:21:01

click

00:21:02

forever 0 hp my laptop

00:21:05

requests in the spring php the babies

00:21:09

web server aka aide disappeared fifty

00:21:11

receives a virtual envelope

00:21:13

it perceives the message as getting

00:21:15

view 0.5 and then it interprets the file

00:21:18

from top to bottom left to right a file

00:21:21

called view 0 php and produces the result

00:21:24

that is inside this file wiki 0 hp

00:21:26

there must be a logical controller

00:21:28

that generates this html,

00:21:30

we'll see it soon, but for now we click

00:21:32

forever 0 that we have Wednesday and Friday and

00:21:35

the slides are loading slowly with 0 see

00:21:37

weeks

00:21:38

do maybe you remember them this is

00:21:42

what this website does

00:21:44

let's see how it does it I

00:21:46

return to the source code

00:21:48

in the ses fichte editor and open the index

00:21:50

. stoves

00:21:51

at the top of this file there are a lot of comments

00:21:53

and in the middle there seems to be no baking

00:21:55

pic code in the stove because if you don’t have a

00:21:57

tag stove with brackets and a question mark

00:21:59

about then you just write in html this

00:22:03

Porechkina because what will the php interpreter do when

00:22:06

it reads

00:22:07

this file from above down from left to right it

00:22:09

will only interpret the code

00:22:11

that it finds between these angle

00:22:13

brackets with a question mark and everything that it

00:22:15

does not recognize as an oven and it just

00:22:17

outputs and html it also outputs

00:22:20

along with other things so this file could be

00:22:22

called index dot html but I

00:22:24

I call everything. stoves at this stage

00:22:26

lectures. stoves are also the most ordinary

00:22:29

html file in the spring. stoves are also some kind of

00:22:33

html,

00:22:34

but let's imagine ourselves as real

00:22:36

engineers and think about how we can

00:22:38

optimize this, it's not very difficult, but you

00:22:41

'll have to go down to copy-paste if you

00:22:44

remember the second week, guess what

00:22:46

I'm going to do, I'm going to go

00:22:48

to the wiki file from

00:22:49

php and select and copy everything and

00:22:52

paste into a new file called VIC

00:22:54

2 points oven and correct both the

00:22:56

URL addresses and voila, based on the fact that we

00:22:58

know the axes,

00:22:59

this option should not be the best for you

00:23:01

about a copy of the paste in general rarely

00:23:03

becomes a good solution, what should we

00:23:05

do in this way correct the

00:23:08

structure of the program in the

00:23:10

eighth week of classes, the

00:23:12

decision

00:23:15

to change the font of each page or the

00:23:16

structure of the template seems all the more strange, so how did you

00:23:19

give it to us yesterday and cope with the

00:23:21

structure of the program,

00:23:26

let's see what all these files have in common

00:23:28

here is Vicodin here is Vic 0 here are

00:23:31

lectures.php here is windex for a pretty penny what,

00:23:36

roughly speaking, do all these files have in

00:23:38

common and how do they differ? Yes, they have

00:23:44

common content; the

00:23:51

lectures differ only in numbers

00:23:53

12 to well, so there is a general scheme,

00:23:58

every time I select one of the

00:24:01

lectures, almost

00:24:02

identical pages open up and I can probably

00:24:05

take advantage of the fact that we

00:24:06

prudently numbered the lectures

00:24:08

if you expand your answer the only thing

00:24:11

that actually distinguishes the files is wiki 1 and

00:24:14

let me scroll so that they are

00:24:15

approximately at the same level, look here

00:24:18

week 0 on top of week 1 week 0 weeks

00:24:23

1 week 0 in general even if you don’t know at all

00:24:28

what a program is, then you can

00:24:30

say that it’s like a game, find

00:24:31

the differences, where is the difference, and when

00:24:35

the name of the titan changes, although it’s not noticeable, it

00:24:37

changes to the same unit in the

00:24:39

h1 tag, and it’s even more difficult for us to notice

00:24:42

because the url is long you, but

00:24:44

they also change a little, at the same time,

00:24:46

I dare to assume that the contents of the page do not change at all,

00:24:50

so the html is exactly the same, at least exactly the

00:24:53

same title, almost the same, it seems like the same thing,

00:24:56

and almost everything else is unchanged

00:24:58

except for small amendments, what should we

00:25:00

do with all this, I’ll show you on the next one

00:25:02

example,

00:25:03

this version 1 here are exactly the same files

00:25:05

plus a couple of new ones

00:25:07

here Yandex. stoves and not even if you have never

00:25:10

seen them before.

00:25:12

you can guess what I'm doing and Mike

00:25:15

to solve this problem based on

00:25:19

what you see

00:25:25

endo want to try no poison

00:25:28

please I

00:25:40

speak please a little bit louder

00:25:50

okay okay and I couldn't hear you very

00:25:53

well but I think you were trying to

00:25:55

say that tags characteristic of the bottom

00:25:58

are taken out do not kill the brackets or are

00:26:01

collected in some common files from files

00:26:05

header. oven peak and footer. stoves and

00:26:09

we will correct something to deal with

00:26:11

your questions about the changing

00:26:13

numbers, if I heard you correctly,

00:26:14

this is the whole point, if we have

00:26:17

excess at the top of the page and at the bottom of the page there is

00:26:19

something to remove, let's just select and

00:26:22

cut out these pieces and put them in a separate

00:26:24

file a similar principle was used in

00:26:26

css where we also removed this from brackets,

00:26:28

placing them in a separate

00:26:30

file,

00:26:31

used a Rick Vaio design

00:26:32

similar to in cloud, all this is the same

00:26:34

as saying, take the contents of the

00:26:37

header.php file, copy and paste it here, but

00:26:40

what is the result now to Yandex. stoves

00:26:43

I have these two lines in lectures.

00:26:46

stoves I have the same two lines of this

00:26:48

century but also. stoves

00:26:49

fresh two lines and now if I want to

00:26:53

correct the names of all my pages or

00:26:55

change the basic structure then I can

00:26:57

do it in one place or rather in

00:26:59

two header and footer respectively

00:27:01

mclaren now the code starts to look

00:27:03

less clear yes but if you think about what is

00:27:05

happening here if I I request VIC

00:27:08

but also . stoves like in this picture when

00:27:12

the view is requested 0.55 what does this mean

00:27:15

literally the browser requests this file the

00:27:18

web server aka dcs fichte takes this

00:27:20

file in the spring dot php and reads it

00:27:23

from top to bottom from left to right in line 1

00:27:25

immediately encounters an open parenthesis

00:27:27

question mark php

00:27:28

rick vaio fedor. oven and go and what

00:27:32

does the oven interpreter do, which is a

00:27:33

built-in web server for your convenience,

00:27:35

it automatically goes to the header.php file and

00:27:38

copies the contents and pastes it here

00:27:40

and then the interpreter comes across ?

00:27:43

and a closed parenthesis and understands that everything

00:27:45

is done further, he blindly outputs the lines

00:27:47

from the second

00:27:48

well, and because this is pure html,

00:27:49

go to line number 8 and perform the

00:27:52

same magical actions, opens the file,

00:27:54

takes the contents and includes it, that is,

00:27:56

inserts it where you need to smoke what

00:27:58

sticks but I I mentioned bugs that need

00:28:00

adjustments, let’s go back a little if

00:28:02

you look at the header. singers, I can

00:28:05

say I took the simple route, which I

00:28:07

sacrificed for the sake of this dubious

00:28:08

improvement of the structure to the structure, yes, let’s

00:28:13

say I sacrificed an important point,

00:28:15

you noted that we had previously changed the

00:28:18

number in the title and the number in another one, I

00:28:21

decided let’s just rename

00:28:23

the page about the problem itself and leave it so,

00:28:25

without a doubt, this is a partial step back,

00:28:28

but it should be noted that on the other hand,

00:28:30

my action took the common

00:28:32

elements out of brackets, and in footer.php,

00:28:34

please note that I also got rid of, although to a

00:28:36

lesser extent, the suad of repetitions

00:28:38

of the same data, so now I

00:28:42

need to do something step forward and

00:28:43

fix all these problems with the title May

00:28:45

let's do that for 4 let's go to the

00:28:49

second version

00:28:50

in which the same files except for one

00:28:52

innovation it's a little more complex but

00:28:54

let's see if we can untangle

00:28:56

what's going on here instead of

00:28:58

asking for header.php and footer.php

00:28:59

senti looks like I'm asking for only one

00:29:02

file which is called the obvious

00:29:03

helpers.php

00:29:04

and I want to note that the helpers.php file is

00:29:07

just a set of functions I wrote to drink

00:29:10

as before, I just called it

00:29:11

helpers.php you see that in lines 3 and 10

00:29:15

I call two functions render

00:29:17

header and renderfooter, they are not out of the box, I wrote

00:29:20

them myself and placed helpers. php

00:29:23

we have already seen this syntax but

00:29:25

did not go into detail, it is obvious that

00:29:27

this is an argument to the render function Fedor as I

00:29:29

understood it one because here is the closing

00:29:32

bracket and here are the opening cats just like

00:29:35

everything everything inside the brackets is the input

00:29:37

data or function argument and what is the type of

00:29:39

this argument if look at the

00:29:41

highlighted piece and what do these

00:29:43

square brackets mean that we parsed

00:29:44

last week yes this is an array, namely an

00:29:47

associative array aka this syntax is

00:29:49

admittedly a little abstruse but it just

00:29:52

passes a key value pair the key is the

00:29:54

title in quotes and the id value is

00:29:56

now fifty if we wrote the code

00:30:00

would all look so simple ses fifty

00:30:03

in quotes

00:30:04

or in curly braces or something like that

00:30:07

in general the key would be 0 and the value would be this

00:30:10

swifty but still, although the syntax of the stove

00:30:13

seems strange, it allows you to connect

00:30:15

numbers using words

00:30:16

keys and values and so what does

00:30:19

this all mean, let's go to helpers.php and

00:30:21

look at this render feeder function.

00:30:25

speech in front of or rather render xygr here is my

00:30:27

function and I know this thanks to the

00:30:30

keyword in punk tire here is everything and this is the

00:30:32

difference from theater to the function takes

00:30:35

an argument yes this I can call it

00:30:37

anything but I called it yes this is for

00:30:40

clarity try to guess especially

00:30:42

if you have programmed before in

00:30:44

high level languages on you 6 what

00:30:46

does equals square brackets mean or what

00:30:49

could it mean he

00:30:51

didn't have that yes it means that if the user

00:30:56

doesn't call the render headers argument

00:30:59

I will still have the delta argument

00:31:01

but its default value there will be an

00:31:03

empty array, this is very convenient, I don’t

00:31:06

have to swear at the user or

00:31:08

say there’s an error in using the function,

00:31:10

I can just give the user

00:31:12

default values if it doesn’t matter to me that they

00:31:16

sorted out my function, and this extract

00:31:18

import function allows us to pass these

00:31:20

variables to data in header.php is

00:31:22

as follows, perhaps this is the last

00:31:25

piece of unusual syntax,

00:31:27

this is a new version of my hodor. . before

00:31:30

it was just a title in brackets

00:31:31

disappeared fifty the same thing with speech alone

00:31:34

now here is something quite strange

00:31:36

let’s simplify it for a minute as follows

00:31:39

apples and here’s how I changed my name

00:31:42

but somehow these

00:31:45

constant opening brackets matches don’t look very good and

00:31:47

then the print function ends up in the

00:31:49

oven, this can be made simpler with

00:31:51

just an equal sign, which is technically a

00:31:53

function f

00:31:54

that can be used instead of prints,

00:31:56

but in reality it’s the same thing, but it looks

00:31:58

better and it’s a kind of syntactically

00:32:01

bonus, if you like, which

00:32:02

improves my cat a little, but also we

00:32:05

will see this soon we need to call this

00:32:07

terribly long function called

00:32:09

html in a hurry and since it

00:32:12

turns out there is such input data

00:32:13

that a user or users can give us

00:32:16

data that can

00:32:18

break our site but we will see this

00:32:21

next week with the java-script language

00:32:23

for now just know that the header.php file

00:32:26

just takes the title that I

00:32:28

passed in, makes sure that it is safe and

00:32:30

can be inserted into a web page and

00:32:32

gives it out as a title and h-1 so

00:32:35

if I go to this version now,

00:32:37

see the title of the lecture is displayed, the

00:32:40

title is displayed, the week number is displayed zero

00:32:42

and note the html that I am

00:32:45

developing is identical to my first

00:32:46

version except for the spaces because I started

00:32:49

formatting my code a little

00:32:50

differently but all the code that was needed is

00:32:53

ready let's stop for a minute

00:32:55

in case anyone has questions

00:32:56

regarding what I wrote well

00:33:00

then let's turn it even tighter to

00:33:03

see how we didn't take

00:33:05

anything else here to improve all hell pier.

00:33:07

there was another function called

00:33:09

renderfooter what is remarkable about

00:33:12

render header and renderfooter

00:33:14

by the way keep in mind that

00:33:17

today the function is extract and just my

00:33:19

way to pass arguments to header.php and

00:33:23

footer.php

00:33:25

then yes I just change the line with the

00:33:30

river and that is and I again went down to

00:33:32

copy-paste, of course there are not a lot of lines here, but

00:33:34

listen, if I just copy and

00:33:36

paste, changing just one single

00:33:38

word and this one word as noted and

00:33:42

here is the footer from here the header everything else is

00:33:44

identical except of course the names of the functions 40

00:33:47

what can we improve let's open

00:33:50

this version where helpers.php why do

00:33:53

n't I make it smarter here write a little

00:33:55

more complex code but call it

00:33:58

display enders that fundamentally

00:34:00

changed it now accepts an argument

00:34:03

or rather two arguments d&d as before

00:34:05

and what could the first word mean

00:34:07

judging by the fact that you see here even

00:34:10

if the syntax here is unfamiliar what

00:34:13

is a dollar sign template

00:34:16

yes and fedor or futa that is, I decided that

00:34:20

if the only thing that changes is

00:34:22

the template that I want to print and by

00:34:25

template I mean the template of the code

00:34:27

that I want to output by adding some

00:34:29

values of these now if it's just a header

00:34:32

or footer why don't I generalize and

00:34:35

call the argument dollar sign

00:34:36

template

00:34:37

and this tricky syntax allows

00:34:39

me to create a variable path path

00:34:42

dollar sign by this variable what does this

00:34:44

syntax mean who knows.

00:34:50

if template header is in quotes or if

00:34:52

template future is in quotes yes then this is a

00:34:54

highlighted line line number eight

00:34:57

simply takes this is exactly an example of a header

00:34:59

and connects it to the stove point since there

00:35:01

was no such operator this operator.

00:35:04

amazing thing.

00:35:06

if you are familiar with java script or java, then you

00:35:09

can use

00:35:10

the + sign to connect, this is a complete headache and

00:35:14

I’m very sorry, but with sixth problem books you

00:35:16

will have to suffer to do this to

00:35:18

connect the lines, why because if

00:35:20

you have one line of this length and the other one

00:35:22

you have you won't be able to just

00:35:23

connect them that instead you will have

00:35:25

to do everything yes I you will have to allocate

00:35:28

memory or use an array of stacks and

00:35:30

you will have to make the array

00:35:31

large enough to hold

00:35:33

this and even a backslash zero then

00:35:35

connect them together using a stern kit

00:35:37

or manually with a for loop

00:35:39

or apply some other technique with a

00:35:41

couple of them, we introduce you in the

00:35:43

problem book number 6 and also a headache, that’s

00:35:45

what I mean when I compare

00:35:47

this and and to see pea spire

00:35:49

you get so many

00:35:51

functional things for free that you can ideally

00:35:52

focus on the most interesting

00:35:54

part of the work on the problem that you want to

00:35:57

solve is at low-level

00:35:58

Alikhanov, these are how

00:36:00

header.php and footer.php are created here

00:36:03

depending on what I call and if

00:36:05

I open the

00:36:06

index dot php pay attention to the

00:36:08

changes instead of calling rows of cores or

00:36:10

render footer whose calling render and

00:36:12

then the name of the template that I want to apply, you will

00:36:15

also see this in the seventh problem book

00:36:17

where we give you the opportunity to use the

00:36:19

same function to create many different

00:36:21

web pages, okay, instead of

00:36:24

endlessly sorting out the details of which you

00:36:25

will meet again in problem book number 7,

00:36:27

let's take a look to start solving a

00:36:30

more interesting problem tass so far

00:36:32

nothing we've done

00:36:34

has saved data, in fact the

00:36:36

only time we

00:36:37

saved anything in lecture was when we had a

00:36:40

very simple haze not too long ago where we

00:36:42

used file I/O all

00:36:44

axes in my opinion, I entered my name, the name of Hana

00:36:47

Yanamari or Andy, and then we saved

00:36:51

this csv file and cone thieves here in Vilnius,

00:36:53

this designation is separated by commas and we

00:36:55

used of a pen i seem to be f print

00:36:57

ef as far as I remember and saved the file

00:36:59

crumpled, well this is the simplest view

00:37:01

database if you are going to make a website

00:37:03

for the freshman competition program

00:37:04

where beginners can

00:37:06

register to participate in what

00:37:08

sport are you you will no doubt want

00:37:09

to operate with this data last

00:37:11

week we did not do anything with the data we

00:37:13

just confirmed you are registered

00:37:15

or maybe I also reported the

00:37:17

freshman curator has everything, but it would be great

00:37:19

if I could give them everything with a vip-file

00:37:21

tipo xl

00:37:22

and even better if I could save these

00:37:24

usernames and their data in

00:37:26

some database until I

00:37:27

want to delete them on a database that

00:37:30

allows you to query information, that is,

00:37:32

in a regular database, today and

00:37:34

next week

00:37:35

we will get acquainted with a technology

00:37:37

called a sequel to a

00:37:38

structured query language, another language

00:37:41

is essentially a programming language, but for

00:37:43

databases from today, the

00:37:45

database should be perceived as

00:37:47

more a complex version of microsoft excel or

00:37:50

google spreadsheets or apple numbers in general

00:37:53

this is a program that allows you to store a

00:37:54

lot of data in rows and columns

00:37:57

just like in excel but what’s great

00:37:59

especially if you are not an excel person is that the

00:38:02

sequel allows you to query

00:38:04

this information using lines of code

00:38:06

thanks to which you can, even if there are a

00:38:09

million rows in your database, find

00:38:11

information very quickly excel is not very

00:38:13

good when it comes to a large amount of

00:38:15

data traction, in fact, until

00:38:17

recently, the pixel allowed

00:38:19

storing only 65535 rows of data, it sounds

00:38:23

like it’s not bad, but I remember how in my

00:38:25

last year I stumbled on this

00:38:27

because I created

00:38:28

all my files for my research and I needed to

00:38:31

quickly analyze them simply

00:38:32

by opening them in Excel and of course my computer

00:38:34

froze because I had more than

00:38:37

65,000 rows, but why exactly 65535, which

00:38:41

apparently made Microsoft darker

00:38:44

effect g like with degrees,

00:38:46

yes, they use a 16-bit value

00:38:50

for the line number and 2 in the sixteenth is

00:38:52

exactly 65536 5 minus 1 because if you

00:38:56

count from zero, then this is the maximum

00:38:58

possible number and it was just

00:39:01

structural decisions

00:39:02

saving 16 bits I was allocated 60 thousand

00:39:06

lines instead of a possible 4 billion dad

00:39:09

now let's imagine this in a network

00:39:11

context what else is good in the sequel again

00:39:13

despite the fact that it is quite powerful

00:39:15

and complex but it comes down to four key

00:39:18

operations four key functions if

00:39:20

you want a choice for searching and retrieving data deletion

00:39:23

for deleting data insertion for

00:39:26

adding from the

00:39:27

database and updating if you have ever

00:39:30

used google spreadsheets and

00:39:32

ambrosia microsoft excel, you probably

00:39:34

performed all these operations yourself

00:39:36

using the keyboard and mouse, inserted

00:39:38

data with your eyes, searched for and selected data,

00:39:41

updated or deleted them, what does this

00:39:44

mean in and actions with fifty installed

00:39:46

program mo sequel is a free

00:39:48

free database very popular

00:39:50

for example facebook uses it to

00:39:52

this day along with

00:39:53

its other tools and many other

00:39:55

very popular sites

00:39:57

widely use it because it is

00:39:59

fast and free although there are

00:40:01

alternatives some of you can

00:40:03

work with them when preparing the

00:40:05

final projects, for example, a screenshot

00:40:07

in an application called oven directly

00:40:09

admin, a simple coincidence that the data from the

00:40:11

web application is also written in the

00:40:13

oven spot language, it is assumed that it

00:40:15

allows you to create a database with its

00:40:17

interface because historically

00:40:19

it has developed that the norm is that a sequel can

00:40:21

only be worked through command

00:40:23

line and it would be inconvenient and difficult to

00:40:25

type a text command to select

00:40:27

data insert data delete data

00:40:28

so someone on the Internet wrote a

00:40:30

program for the network that allows us

00:40:32

to manage the data in our database,

00:40:34

it’s like double clicking on the excel icon it

00:40:36

just launches in the version and you will

00:40:38

use it next week not in the

00:40:40

sixth problem book, but to develop the

00:40:42

so-called everything from the fiv tag fine and in

00:40:44

which there will be a database of users

00:40:46

with their names, passwords and the number of

00:40:48

dollars in their bank accounts, there should

00:40:50

be a database where the

00:40:51

symbols and the number of shares that

00:40:53

the user has bought will be stored with the virtual

00:40:55

dollars that you give them, it

00:40:57

should also allow users

00:40:59

to register on the site so that even

00:41:00

your friends can go to the site,

00:41:02

register, log in and

00:41:04

have fun trying to find errors in

00:41:06

your code and bugs on the website, they

00:41:08

will be able to register, it will simply be

00:41:10

added thanks to the code that you

00:41:11

write for your database, for

00:41:13

example, here is a screenshot of the database,

00:41:15

which can roughly turn out to be an example

00:41:17

from previous years, similar to a mini

00:41:19

excel file stored in our database.

00:41:22

May sequel she is life

00:41:25

and on the left obviously and assigned each

00:41:27

user a unique number in the second

00:41:29

column the name a username by the way is here and

00:41:31

mine she on the right they are assigned a certain

00:41:34

hash actually this is sometimes but not a simple

00:41:38

text password it is encrypted if

00:41:40

you want or hashed sometimes we also

00:41:42

let's get back to this but if you've ever

00:41:44

read an article about how

00:41:46

bank passwords or

00:41:48

website passwords are hacked then you know that this

00:41:50

happens in two ways

00:41:51

here we have a sample of six

00:41:53

users all you can now

00:41:55

find out by window or by hacking the system

00:41:58

what passwords are these six users

00:42:00

and if you have ever received a

00:42:02

warning from a company or website

00:42:05

that said sorry our

00:42:07

database has been hacked please change

00:42:08

your password what does this mean

00:42:10

but one possibility is that this company is

00:42:12

so stupid that they stored your password in

00:42:14

such a columns in unencrypted form,

00:42:16

this means that an attacker who

00:42:18

hacked the database and now knows your

00:42:20

username and password is the worst of the

00:42:22

options, and as you will see in problem book

00:42:24

number seven, it’s so easy for you to avoid there is

00:42:26

no justification for such

00:42:28

stupidity on today’s

00:42:29

Internet,

00:42:30

but we will find articles in which we will see that

00:42:32

similar ones nevertheless still

00:42:33

happen the second option perhaps

00:42:35

an attacker stole such a version of the

00:42:38

database, this is also bad because now

00:42:40

they know that I have six clients

00:42:41

know exactly 6 users knows the

00:42:44

encrypted versions or hash codes of the

00:42:45

passwords of these six users sex

00:42:48

watch any of you who worked on the

00:42:50

second for hacker's summer residents where you need to

00:42:52

crack a password or just saw

00:42:54

this task there, tell me why it's also not

00:42:58

very good if the attacker

00:43:00

got the password hash correctly,

00:43:10

the attacker can write code like

00:43:12

what you wrote for the hacker

00:43:13

problem book in which they go through all the

00:43:15

words from the dictionary or all possible

00:43:17

combinations from a to z

00:43:18

and this is what we need 9 it seems that this is a

00:43:20

lot and this is so le camp

00:43:22

second. it’s fast and in general, that

00:43:24

was the point of that problem book, to take similar

00:43:26

material and get to the bottom of its original

00:43:28

hidden values, so we’ll figure out

00:43:30

how to store data as efficiently as possible.

00:43:32

Fortunately, it turns out that in the mass of kvoll

00:43:34

there are data types and one of the most

00:43:36

interesting tasks when creating a

00:43:37

database To be honest, it's deciding how

00:43:39

best to represent the data,

00:43:41

whether phone numbers are represented as a whole big

00:43:42

whole or Lanka maybe as a

00:43:44

sequence of characters

00:43:45

and such a decision can turn out to be

00:43:47

very important there is one old funny

00:43:49

story on this topic when Mark Zuckerberg

00:43:51

created Facebook so he wrote it on the

00:43:53

Facebook singers before so far, for the most

00:43:55

part, it has been written to bake a picket, one of the

00:43:57

difficulties that they immediately

00:43:58

encountered was scaling when

00:44:00

they added a school, another school, and another,

00:44:03

as far as I know, one of the first

00:44:04

decisions was beyond the means of copying

00:44:06

and pasting some databases,

00:44:08

some codes for the gorvat to work on

00:44:10

its server, MIT on

00:44:11

its own, and that’s why some of you

00:44:14

may remember you couldn’t add

00:44:15

people from other networks as friends,

00:44:17

maybe 10 years ago you didn’t have

00:44:19

friends at MIT or

00:44:20

Harvard, well, you couldn’t cover all of these,

00:44:22

partly for this reason, serious The

00:44:24

carrot challenge for companies like

00:44:26

Facebook is processing hundreds of thousands of

00:44:28

millions of requests per second, so what

00:44:30

we're going to talk about this week has a

00:44:31

lot to do with creating good

00:44:33

software, their well-

00:44:35

known and effective tool

00:44:37

that most users can use,

00:44:38

we'll look at

00:44:40

things like indexing and search. for today

00:44:42

that's all see you on Wednesday

00:44:43

translated and voiced by vert

00:44:47

diver studio commissioned by java rush

00:44:49

[music]

00:44:52

you can add or subtract and you don’t

00:44:54

have to stick to the

00:44:56

allocated amount of memory once and for all what is it

00:44:58

called what’s going on you what is

00:45:02

he giving a lecture about you can use the

00:45:04

chalk highlight function memory,

00:45:06

why don’t they move in their hands, well, it’s

00:45:10

normal to sleep, they just hang like

00:45:13

two big sausages, that’s normal, yes, I

00:45:19

think he just accidentally mixed up

00:45:21

the deodorant with super glue

Description:

Доп. материалы и задачи к лекции - https://javarush.com/quests/lectures?quest=QUEST_HARVARD_CS50&level=8 Весь курс CS50 - https://javarush.com/quests/QUEST_HARVARD_CS50 Больше практики по программированию — https://javarush.com/user/track/a?jrm_source=youtube.com&jrm_medium=link_under_video&out=jrmain CS50, или Computer Science 50 — это курс Гарвардского университета, посвящённый основам программирования. Шестнадцатая серия цикла продолжает рассматривать язык PHP, теперь для разработки веб-приложений, а также знакомит с базами данных и MySQL. Впервые в истории студенты двух учебных заведений — Гарварда и Йеля — при помощи современных технологий параллельно проходят обучение на курсе.

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