/dpt/ - Daily Programming Thread

>>57528432
First for D

Mapping and filtering is the bread and butter of every functional programmer's toolbox. Uh. It doesn't matter if you do it with the map and filter functions or list comprehensions. Recall how we solved the problem of finding right triangles with a certain circumference. With imperative programming, we would have solved it by nesting three loops and then testing if the current combination satisfies a right triangle and if it has the right perimeter. If that's the case, we would have printed it out to the screen or something. In functional programming, that pattern is achieved with mapping and filtering. You make a function that takes a value and produces some result. We map that function over a list of values and then we filter the resulting list out for the results that satisfy our search. Thanks to Haskell's laziness, even if you map something over a list several times and filter it several times, it will only pass over the list once.

C# or Java?

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Mummy beat me up for wearing her clothes while programming. I tried to explain that someone on 4chan said it makes you a better programmer, but she was having none of it.

>>57528454
Trust me if you have to chose between trash and poop you should go for Java.

does /dpt/ have discord channel?

>>57528432
OOP more like POOP

>>57528460
Is your mummy cute?

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> tfw to smart for functional programming

Friendly reminder that monads are impure.

>>57528441
>Mapping and filtering is the bread and butter of every functional programmer's toolbox
No
Map and filter are just two functions.
It's only the kitchen sink languages that think by adding them they're suddenly functional.

Python

>>57528477
Ok, but what if I want to get a job?

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What's the difference between OOP and functional?

Can you do both at the same time?

>>57528460
Post a pic

>>57528528
http://www.scala-lang.org/

>>57528528
Functional programming is what you use if you want to bang hipster chicks at programming conferences

>>57528432

if( op.image.isAnime() == "true" ) reply("fuck you for watching anime \n>>>/a/");

How does everyone like my one liner?

>>57528528
>Can you do both at the same time?
Not well. See >>57528546

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>>57528535
O-ok. Please don't be mean.

>>57528550

0

>>57528550
>true is a string
for what purpose

>>57528564
That's not you, kys.

>>57528605
I don't want to kiss you

>>57528591
for readability

>>57528627
>

>>57528625
Not the person you're replying to, but "kys" is short for "Kill YourSelf"

so apparently std::vector.insert segfaults if you try to insert at a location outside its current size, but within its capacity

>>57528694
What says the documentation?

>>57528657
Only if you ask me nicely

>>57528694
http://www.cplusplus.com/reference/vector/vector/operator[]/
>Portable programs should never call this function with an argument n that is out of range, since this causes undefined behavior.

You're a code monkey anon.

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I still don't understand the difference between OOP and functional, /dpt/.

You're not being very helpful, I'm going back to /pol/.

Is there a good programming book with anime girls/manga illustrations?

>>57528825
>stupid
>frogposter
>/pol/ fag

Why am I not surprised?
When will you newfags learn?

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>>57528825
You're not smart enough

>can't

>>57528839
>newfag
Wtf? I've been here since 2015. I'm an old fag.

>>57528454
C#, and use .NET core.

>>57528460
I feel as though we need to conduct a proper scientific study on this subject to show whether or not this has any actual effect on programming ability.

>>57528694
Sounds like undefined behavior.

>>57528825
OOP: Describe program as an interaction between objects
Functional: Describe program as a composition of functions

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>>57528564
>best guess for this image: sissy
wew lad

Pure functional programming admits side effects as long as you never break the rule that the same input always leads to the same output.

Monads do this by making the output a computation and not the result of a computation. Linear/affine types do this by making it impossible to call the function with the same input again.

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>>57528904
>OOP: Describe program as an interaction between objects
>Functional: Describe program as a composition of functions

But in JavaScript, and I presume other languages, you can put functions inside objects and objects inside functions. I'm not really following.

I'm starting to think functional and OOP are both meme words that don't really mean anything.

>>57528960
They're not mutually exclusive.

>>57528960
Trolling too hard anon.

>>57528971
Wish I was trolling, lad. I honestly want to understand the difference.

>>57528994
I presume you meant to reply to >>57528974?

>>57528432
I'm supposed to implement a ternary tree that holds generic objects in Java. I can't figure out how I'm supposed to compare different values if they're not simple numbers. This is bullshit.

I replaced an array in my class with a vector, do I not need to call delete and there for do not need a destructor etc?

>>57529031
https://docs.oracle.com/javase/7/docs/api/java/util/Comparator.html

>>57529042
That wouldn't work with objects that don't have Comparator implemented.

>>57528960
OOP has become pretty meaningless in the sense that no one can seem to agree on what exactly it means

>>57528651

*kisses you back*

>>57529031
Compare them by reference?

>>57529081
Comparable is when the objects compare themselves. Comparator is a so-called "functional interface" and allows the user to supply an arbitrary comparison function.

>>57529151
The objective is to make a ternary array with arbitrary Objects, including ones that don't have Comparable implemented or have a Comparator class supplied with them.

The only option is to compare the references as far as I see and I don't even know how Java determines those.

Can you find the length of an array if you get it from a method that returns in?
I.E.

getArray().length;

or something like that.

>>57529181
If that's truly the objective then it's a retarded one. Probably you're supposed to use generics.

>>57529181
use hashCode()?

>>57528960
JavaScript isn't OOP or functional and it certainly isn't both

Did you only ask the question because you wanted to be like "hahaha wrong"

Working on a C program that eventually outputs a shit ton of numbers

My question is, is there a way to sort this? I want to get rid of all the duplicates I'm printing and only print least to greatest?

Is there any way to do this in my code??

>>57529203

class TreeNode<T extends Comparable<T>> {
    private TreeNode parent = null;
    private TreeNode leftNode = null;
    private TreeNode middleNode = null;
    private TreeNode rightNode = null;
    private Object T = null;
}

Would something like this work?

I'm just going to be a bit more liberal in my interpretation of the assignment since the guys english sucks ass. This would enforce any type to have a comparable interface right?

>>57529289
>Would something like this work?
Not quite.

class TreeNode<T extends Comparable<T>> {
    private TreeNode<T> parent = null;
    private TreeNode<T> leftNode = null;
    private TreeNode<T> middleNode = null;
    private TreeNode<T> rightNode = null;
    private T data = null;
}

>This would enforce any type to have a comparable interface right?
Yes.

>>57529248
>JavaScript isn't OOP
It is.

>>57529309
thanks man

>>57529248
But JavaScript can be object oriented or functional depending on how you use it, anon.

>>57529278
You apparently have no code so, no.

http://www.cplusplus.com/reference/cstdlib/qsort/

I'm trying to code a new large project but with better OOP than my last. So what is the best way to store objects A for another object B to loop through them all when doing its procedures. That's a general idea of the problem but it pops up in many ways.

Should I be using global lists for holding certain types? Using a singleton to communicate between A and B when necessary? It seems like you could up with many confusing singletons as a project begins to expand.

>>57529278
>Is there any way to do this in my code?
no, you have to be a magician to do it. are you retarded or something? missed your hogwarts invite?

>>57529278
Abuse the fact that you can assign a number to it's index in an array.

array[5] = 2;

would mean that the number 5 has 2 instances in your data set.

Code is one of those buzzwords that makes me cringe as if Rosie O'Donnell came out with a sex tape.

Do you call your code...code? Or do you call it something else?

This is about the noun rather than the verb.

How would I go about sorting an array from lowest to highest numbers?
It's given values but not in any particular order.

>>57529416
I call my code code. And I call my work coding.

>>57529379
class A {
public: void func() { ;; }
}

class B: {
private: vector<A> my_As;
public: void do_some() {
for (unsigned int i=0; i<my_As.size(); i++) {
my_As.at(i).func();
}

}

>>57529363
>You apparently have no code so, no.
I do its just no one will understand it. I've tried asking for help before. I'm done with it now but its garbage. I just need to get rid of the duplicates its printing

I see qsort will sort from least to greatest which is good but will it get rid of duplicates? In the code I've forked a few times which I believe is the reason I'm getting duplicates so in the for loop that's printing everything out I was hoping there was something in c that ignores duplicates before it outputs.

>>57529416
I call it what it is


art

>>57529379
If B is the only thing that needs that collection of As, you could make it a field of B. Otherwise, pass it into Bs methods that use it.

>>57529465
It's easy to remove duplicates when a sequence is already sorted.

>>57529391
see here smartass>>57529465

>Have to modify a Microsoft example driver for research
>Test out installing driver to VM, which I have successfully installed other driver examples to
>Passes preparation, but fails install
>Error is vague, just says that DriverTestTasks::_RunProcess failed
>Says to check the Driver Test Group Explorer
>Navigate to Driver Install in said explorer, see it failed
>Under this is just one file, Driver Install 00001.wtl
>Open it up
>Visual Studio bitching about line endings being inconsistent, but ignore that
>Entire file is XML
>Almost unreadable XML

Would it be too much to ask Microsoft for readable errors?

>>57528960

Most languages in modern usage are multi-paradigm. Also, JavaScript is kind of weird with how it does OOP, because it's based on the Self programming language's style of OOP.

>>57529511
>multi-paradigm

>>57529459
>coding
makes me cringe. sounds like the main part of the work is typing in code. if the main part of your work is not thinking, reading or atleast debugging, but actually typing in code, you must be a pajeet and/or """webdev""". or still a student.

>>57529511
>Would it be too much to ask Microsoft for readable errors?
They failed at it for 30 years. And it will never change. Error reporting need high skilled developers.

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>>57528564
well thats not you, this picture is from 2014.

>>57529524
>typing in code
No I don't type code. I code code. Only code monkeys type code. You're probably a code monkey, otherwise you wouldn't have made that mistake. By the way you don't like the verb code, so I already know that you're a code monkey.
Two proofs == TRUTH

>>57529538
that's an elaborate way of calling someone a 1 year old baby

>>57528432
so im not a new programmer or anything but i came to ask a question

what the fuck should i do

i want to get into web design and stuff so i can make sexy web pages but i dont know how to design websites at all. i know a bit about css / js / html but how the fuck do you make a website not look like its from the 90s?

>>57529586
>No I don't type code.
so you write down the source code (wait i highlight it for you)
>source
>code
on paper or are you using some voice to text?

>>57529596
>how the fuck do you make a website not look like its from the 90s

body {
  font: 12px sans-serif;
  margin: 0 auto;
  max-width: 1024px;
}

:O

Can someone help me with this?
>>221023

>>57529640
I code code, moron. One is a verb, one is a noun. Is it that hard for you?

>>57529685
>>57529640

I honestly didn't think the questions I asked would cause this much debate amongst two answerers...

>>57529737
>I honestly didn't think the questions I asked would cause this much shitposting
ftfy

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am I retarded? what's causing this error?

>>57529737
Welcome to /dpt/.

>How do you get the average of two ints again?~~~

>>57529947
You're calling close no matter the answer, Randy.

>>57529947
Something between your chair and your keyboard

What book would be good to begin programming in C ?

>>57529947
Randy Hodge is a gay ass name, faggot.

>>57529984
See OP pic

>>57530015
OP pic is a lie. There are no C programming books with a cute loli on the cover.

>>57529947
Why does Java love using an atrocious amount of naming conventions, Randy?

>>57530039
That's not a loli

>>57529984
The book in OP's pic

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>>57529977
it didnt help, checked those digits though
>>57529978
>>57530003
i'm well aware
>>57530064
it's the designated shitting language

I am learning the godless abomination that is Python, and I need to run multiple threads simultaneously in perpetuity for an assignment.
Only problem is that as far as I can tell GIL prevents this from happening under any circumstances.
Am I wrong, or is my professor just fucking retarded? I'm learning towards the latter, but I'm equally willing to accept that I'm just an idiot.

>>57530126
Your while loop doesn't contain a boolean expression. My suggestion is to use a language that is not derived from C.

Say I have this array

char array[100][100]; // [rows][columns]

and then I put a random '+' in some of them

for (int i = 0; i < 100; i++){ //rows
     for (int j = 0; j < 100; j++){ //columns
          if ((rand % 100) < 10){
               array[i][j] = '+';
          }
     }
}

then picked a random array

//random pick: array[56][13];

what would be the easiest way of telling if any of the elements on the "56th row"

array[56][0];
array[56][1];
array[56][2];
...

had a '+' sign in them? How would I do it where the "checking" of the element starts at the random array and them checks to it's immediate left and right, then 1 away on left and right, 2 away from it? Like:

//assuming random array is array[56][13];
array[56][14];
array[56][12];
//then,
array[56][15]
array[56][11];
...

any tips or resources are helpful. thanks.

>>57530173
>learning
Fuck, meant leaning. The point remains the same, though.

best language for cute traps?

>>57530211
Python. Only real men are allowed to use C.

fug i just wasted 20 minutes figuring out how to shuffle an array and there is a vector function called random_shuffle!!!!!!!!!!!!!

>>57530211
D

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>>57530180
Got it further up there, it's telling me that it goes unused though. But I think the ###PROBLEMATIC line is the =kY.nextLine();

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# sudo openssl dhparam 4096 -out dhp.pem
# sudo letsencrypt certonly --standalone -d example.noip.me --rsa-key-size 4096

import BaseHTTPServer, base64, ssl
from SocketServer import ThreadingMixIn
from SimpleHTTPServer import SimpleHTTPRequestHandler

class AuthHandler(SimpleHTTPRequestHandler):
    def end_headers(self):
        self.send_header("Strict-Transport-Security", "max-age=63072000; includeSubDomains")
        SimpleHTTPRequestHandler.end_headers(self)

    def do_HEAD(self):
        self.send_response(200)
        self.send_header('Content-type', 'text/html')
        self.end_headers()

    def do_AUTHHEAD(self):
        self.send_response(401)
        self.send_header('WWW-Authenticate', 'Basic realm=\"Gensokyo\"')
        self.send_header('Content-type', 'text/html')
        self.end_headers()

    def do_GET(self):
        credentials = base64.b64encode(b'yakumo_ran:yellow800')
        if self.headers.getheader('Authorization') == None:
            self.do_AUTHHEAD()
            self.wfile.write('403 Forbidden - Your IP Has Been Reported')
            pass
        elif self.headers.getheader('Authorization') == 'Basic '+credentials:
            SimpleHTTPRequestHandler.do_GET(self)
            pass
        else:
            self.do_HEAD()
            self.wfile.write('403 Forbidden - Your IP Has Been Reported')
            pass

class ThreadedHTTPServer(ThreadingMixIn, BaseHTTPServer.HTTPServer):
    """>muh indents"""
def main():
    try:
        httpd = ThreadedHTTPServer(('', 4443), AuthHandler)
        httpd.socket = ssl.wrap_socket(httpd.socket, certfile='/home/ubuntu/server.pem', server_side=True, ssl_version=ssl.PROTOCOL_TLSv1_2, ciphers='ECDHE-RSA-AES256-GCM-SHA384 ECDHE-RSA-AES256-SHA384 ECDHE-RSA-AES256-SHA', do_handshake_on_connect=True)
        httpd.serve_forever()

    except KeyboardInterrupt:
        print(' received, shutting down server')
        httpd.shutdown()

if __name__ == '__main__':
    main()

secure_server.py

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is this book worth buying for €45? My professor said its basically a design pattern book on concurrency. So im not sure if he was dissing it.

>>57529947

import java.util.Scanner;

public class Retarded {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        System.out.print("Perform another calculation? ");
        char r = s.next().charAt(0);

        boolean cont = (r == 'y' || r == 'Y') ? true : false;

        while (cont) {
            System.out.println("Why are your variables, colourscheme, fonts, and OS so shit?");
        }
    }
}

So... figured out that Microsoft includes an HTML file along with all of the WTL files, and that can be opened for a much more readable error format (it still begs the question of WHY?)

Found out my error... sort of. But I am not sure what a valid solution might be. When installing the driver, it runs a command:

"C:\DriverTest\devcon.exe" -f install C:\DriverTest\Drivers\netvmini630.inf dev

This returns an error code of 2, indicating a file was not found. Investigating the folder C:\DriverTest\Drivers, I find the following files:
netvmini630.cat
netvmini630.cer
netvmini630.inf
netvmini630.sys

It clearly can't be complaining that it can't find netvmini630.inf. So looking into this folder, I see it references netvmini630.cat, which is also there, but also see a bunch of paths that look like

%NetVMini.DeviceDesc% = NetVMini.ndi, root\NetVMini630_a

I'm thinking it's supposed to be referencing some other file NetVMini.ndi, but there's no such file anywhere in the solution, and I'm not entirely certain how one would generate this kind of crap.

>>57530249
In while(), your doing an assignment, not a value check.

how do you stick with a project until it's finished?

>>57530341
be paid to do so

>>57530184
>what would be the easiest way of telling if any of the elements on the "56th row"
Using memchr function.
>t's immediate left and right, then 1 away on left and right,
You have a non-standard counterpart memrchr.

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>>57530341
hard work and discipline

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Question:

when you see on job postings that a job has a salary of $ 85K, how much do you actually take home?

Why have a job that pays a lot if you are taxed to death?

How do I sort numbers from smallest to largest?
Is there a class library I could use?

>>57530396
Perform

while( project.isFinished() == false )
{
    me.workon(project);
}

On yourself

>>57530435
what country are you in? In America, you would be taxed at 25% today, but that should go down under Trump

>>57530220
why would you wanna be a real man?

>>57530465

while(!isFinished(project)) {
    workon(project);
}

>>57530435
>>57530470
Nah. Definitely not 25%. You're forgetting about local and state tax, SS + other payroll taxes.

... and gas tax and sales tax and breathing tax

Pretty much everything is taxed

>>57530461

sort [5, 4, 3, 2, 1]

>>57530511
I didn't want to break it down state by state. That's just federal income tax. Yeah, the SS in America is almost as bad as Germany's

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Fuck
Android
Studio

>>57529423
Quicksort is the most versatile solution

>>57530470
but how is he gonna build the wall then?

>>57530509
But what if you want to team up with someone else, and because you're a degenerate transsexual, you decided to listen to the memes and didn't program in OOP. Now you have to port the code you wrote 5 years ago so that it could work better

Meanwhile I just need a new class that has a vector<person> and implement abstractions on a new level

>>57530435
>>57530470
>>57530511
You're all forgetting that our tax system is progressive.

You only get taxed at 25% on the income you make past $37,000 or so, for example.

There's also the fact that all of your tax breaks will save you that 25% off the top, so putting into 401k and other pre-tax benefits are effectively 25% cheaper, not to mention all of the breaks you can get by buying a house and other things of that nature.

Although, if you live in a cucked state with lots of state taxes, I can't help you there.

Texas has few taxes in comparison to other states, and no state income tax.

>>57530615
Mexico is going to pay for it

>>57529278
Dynamically allocate an array of integers, and increment the value at the numbers' position by one every time you see itl

Making a program that archives 4chan boards in C# but I'm stuck.

I'm downloading pictures in a thread using WebClient DownloadFileAsync but some images just don't download and end up with 0 Bytes.

For example in this thread >>>/h/4397145 out of the 243 images (not counting the 8 gifs because I skip gifs and webms atm), 14 came out with 0 Bytes.

Now, is this a problem with DownloadFileAsync or with 4chan?
And how would you handle it?
Just check the filesize when the download finishes and re-download?

>>57530653
4chan spot you. Your program must be more discrete.

>>57530461
What language?

>>57530679
they're pretty shit at spotting if only 5% of the images don't download

>>57528825
Ones a convoluted paradigm used by Pajeets, the other is a convoluted paradigm used by white PhD holders.
How can you not tell he difference?

>>57530653
>Just check the filesize when the download finishes and re-download?
That's what I would do. Computationally cheap and easy to implement. Not elegant, but easy.

Can I get some book recommendations for pthreads and mutexes?

>>57530685
Befunge

>>57530715
Which is which?
Provide evidence to support your claim.

>>57530695
That's enough to annoy you.

How many connections in // did you open?

If I'm making a multiplayer game where users connect to a dedicated server, how do I prevent people from hacking the client side code and making for example hacked clients that ignore all visibility restrictions?

What are some optimizations I can do in C/C++ that would improve ARM performance (Raspberry Pi)?

>>57530753
You must not send hidden data to clients. Only what they need to know otherwise there will be hacked clients.

>>57530461

>How do I sort numbers from smallest to largest?
There's a number of methods. The simplest of these is bubble sort, but it has a bad runtime complexity, and even then, does not perform as well as other sorting algorithms that run in O(n^2) time.

The simplest method among those that run in O(n log n) time (the best you can get for a comparison sort) is called merge sort. Simply put, you divide a list in half, sort it, and then merge the two lists together. Since a list of size 1 is already sorted, you can end at a base case of 1. As an example, consider the list [4, 2, 1, 3]. Dividing this in 2 gives us [4,2] and [1,3]. On the list [4,2], we sort again receiving [4] and [2]. Merging together, we see that 2 comes before 4, and create the list [2,4]. Similarly with [1,3] we sort and merge, and get [1,3] again. Merging again, we see two sorted lists, [2,4] and [1,3]. We construct a new list by pulling the smallest of the first elements of each sub-list at each iteration. So first we pull 1 from the second list, then 2 from the first list, then 3 from the second list, and 4 from the first list. The result is [1,2,3,4].

There's a number of other methods of sorting integers in n log n time, but merge sort is the easiest to explain, I think. The most effective ones, which are likely used by your language's standard library, are hybrid sorts, which combine multiple sorting algorithms to get the best cases out of both of them.

>>57530546

FUCK
VISUAL
STUDIO

>>57530749
I'm limiting it to 10 simultaneous connections at the moment.
I'm just gonna do the >>57530719 approach and re-download anything with 0 bytes

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Is there any point in having a GitHub account if I have little experience in programming useful things?

>>57530753
Get their position on the map, and find out what they are supposed to and not supposed to see, and just send them that information.

>>57530795
Have you considered Haskell?

>>57530794
>I'm limiting it to 10 simultaneous connections at the moment.
Try 4.

>>57530795
Is there any point in anything?

>>57530795
Yes, to motivate you to make useful things. Also, useless things can be pretty useful for employers to gauge your expertise.

>>57530546
>not using Xamarin with Visual Studio
>smug_loli_wearing_a_.NET_Foundation_tshirt.png

>tfw i was about to prove something that was already proven in the lecture with the proof in the script being two pages long
WEW dodged a bullet there

>>57530910
>not using Xamarin with Visual Studio
>smug_loli_wearing_a_.NET_Foundation_tshirt.png

how do i install visual studio on linux, you dirty faggot

I'm wrapping a C library in Rust and it has functions for global initialization and cleanup. Because I want cleanup to be handled by RAII, I'm making a type for the "context" with an unsafe constructor since there's no real way to check that the library is only initialized once (more so that it's not terminated globally by a second context while the first is still alive). Fight me.

>>57531075
Or you could just use C and stop wasting neural time with memes.

>>57531075

>there's no real way to check that the library is only initialized once
Keep a global boolean variable called initialized. When you first initialize the library, set it to true. On further attempts to initialize it, check if it is already initialized. Don't do anything if it is. On cleanup, do nothing if initialized is false, and once cleaned up, set initialized variable to true again.

RAII makes little sense if you have a cleanup and initialize function, since it can be handled by those functions.

But I don't really know everything about how your library is set up. Do whatever seems most reasonable.

>>57530410
hm yeah
no adderal here tho

>>57530396
yeah but first you have to learn a bit

>>57531075
>there's no real way to check that the library is only initialized once
There's a way to check that the library is only initialized once through your wrapper. Isn't that good enough?

>>57530341

Force of fucking will. Just do thing until it's done. Take breaks for food or sleep, but don't go working on another project, or spend 9 hours playing Minecraft instead of programming.

>>57531178
That only works if the library is only used through this particular wrapper. Because it's not possible to enforce or even check that at all, I'm going to just call it unsafe.

>RAII makes little sense if you have a cleanup and initialize function, since it can be handled by those functions.
RAII means that the destructor (and thus the cleanup function) is called in the event of a panic or whatever automatically.

>>57531247
Nope. I'm not going to lie to the compiler about being safe, just because the standard use case is safe, on principle.

What is the best library for decompressing MP4?

>>57530435
If you have no exemptions, depending upon the state, 35-40%. I was earning $50k and was taxed 35% in VA.

>>57529947
Try .next() instead of nextline

>>57531313
libffmpeg

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As usual, working on my terminal emulator. Adding support for word cursor movements, like the ones in vim.

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How do I become a hacker /g/?

>>57531614
install Solus

>>57531614
Buy an axe.

>>57531614
dress up like a girl and install gentoo

>>57528432
I'm trying to make a simple image matching program in c++ using libjpeg where I take a sample image and try to find it (in any reasonable orientation) and I can detect if the sample image is a match to the group of pixels I'm scanning, but I got a problem.

I don't have a good search algorithm to look through the larger image being searched for a group of pixels. The only thing I can come up with is check the whole image with the sample oriented in 90 degree intervals, then 45 then 22.5 etc until match is within a reasonable margin of error, but that would take a long ass time. Idk how I would do size as well within a reasonable amount of time.

am only novice programmer pls no bully :(

>>57531749
Is there any particular reason why you can't memcmp the individual pixels?

You've already made it this far, don't be dumb.

Have you EVER used a list over a vector? Be honest.

>>57531749
>Hey average color of the two images
>Check for equivalence
>Done?

>>57531954
as far as I understand that wouldn't work for rotated images or ones that arent exact matches

I'm ultimately trying to make a facial recognition program and I don't know bidimensional regression so I gotta use a sample photo of a face.

would also like to be able to locate the face.

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This is for android:

Can someone help me with my algorithm?

I mocked it up, I use a single bitmap that stretches to the size of the relativelayout on the screen.

All I want is to have my ListView that exists as a child of my RelativeLayout to exist within the borders of the image in the background.

I have to play with the margin values, and determine them at runtime based on various values like:

Resolution of the screen
Pixel Density
Size of the bitmap in pixels

I can get it working for some screens, but when I test on different ones it fucks up hard.

How is this done in the industry? Do people actually have to code each individual screen size/density in?
There must be some algorithm that can do it for you.

>>57532007
?
would this work?
do you mean get one average colour value from all the pixels in the entire image and compare?

>>57532025
Probably, most of the time anyway.

>>57532064
I couldn't compare the entire images though,
if one is a rainforest with some white dude's face that'll average out to mostly green, and I'm trying to find the face which is mostly beige, then they wouldn't match

Is there something I'm missing?

>>57532097
compare average color in 16 different regions instead of just one.

I'm sure this is how fuzzy image comparison works, only it's probably more involved.

>>57532097
My original description wasn't accurate, I meant to see if there is a copy of my sample image located somewhere (at some size or orientation) inside the image being checked

>>57532113
oh, ok thanks I'll try this

What's this style of if statements called?
#define new_max(x,y) ((x) >= (y)) ? (x) : (y)

And does it do anything better than a normal if statement performance wise?

>>57532175
Conditional assignment.
Almost definitely not.

>>57532175
>What's this style of if statements called?
Ternary statement, or conditional statement.
>And does it do anything better than a normal if statement performance wise?
No. The only difference between it and a "normal" if statement are the places they can be used.

>>57532175
you're inlining a trivial operation that would otherwise have resulted in another function call and and a costly stack push.

It's called a ternary operator.
Also, you don't need a >= in your max() function because the output would be the same if they were both equal.

>>57528525
Yes

Why are high level languages like javascript and python better than more cumbersome languages like C and C++

>>57532366
>more cumbersome
?

Is cucumber a fruit?

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Rate my explode function, /g/oys

pic related (code is too long) to post

>>57532366
Explain what's so cumbersome about C without using memes.

>>57532442
JavaScript:

var s = "Hello world!";

C:

char *s = malloc(sizeof(char) * strlen("Hello world!"));
strcpy(s, "Hello world!");

>>57532417
2/10

did not even read the code because of the spacing of the comments.

>>57528546
>TYPE INFERENCE
>So the type system doesn’t feel so static. Don’t work for the type system. Let the type system work for you!
>that example snippet
gross.

>>57532474
Do you want to write your code quickly or make your program run quickly?

>>57532493
I'm starting to regard relying on type inference as a code smell
Usually in my Haskell projects, when I'm at the point where I'm not explicitly denoting the type signature of a function, it means I've lost the plot and gone too far in a few places.

>>57532474
Your C example is fucking garbage.

// Automatic duration, modifiable
char s[] = "Hello world!";

// Static duration, non-modifiable
char *s = "Hello world!";

// Dynamic duration, modifiable
// Non-ISO stanadard, but is POSIX standard, and is trivial to do yourself
char *s = strdup("Hello world!");

>>57532474

char *s = "Hello world!";

This is standards-conforming C.
Why don't you try it?

>>57532498
Write my code quickly, hands down. Less work for more pay

>>57532474
Nigger that's some pretty shitty bait.

char *s = "Hello world!";

>>57532474
He said without using memes kid.
>uselessly calling malloc

>>57532533
Well what do you want to do?

>>57532520
>char *s = strdup("Hello world!");

I seriously hope you people don't do this.
Instead of having a string be a static pointer to read-only data in the executable, you've turned a a string initialization into SEVERAL FUNCTION CALLS that cannot be optimized away.

>>57532539
Get paid to write shit code for 2 years then quit programming and move into management, hopefully making 6 figs by the time I'm 30.

There's no hope for a developer in his late 30s and above, so I wanna work on my career as fast as I can

>>57532511
the .toInt on the end of what looks like a variable definition there using "type inference" triggered me so much. Assuming the language supports implicit casting it would be easier and clearer to just explicitly type it as an int and run the function.

>>57532498

A := B;

Compiles exactly the same as a memcpy call. The meme that languages that are harder to write in are faster is a fallacy.

>>57532537
>not using strdup

>>57532555
>I seriously hope you people don't do this.
If you want a MODIFIABLE dynamic string, this is what you would do.
It's not something that I really do myself, as I usually just pass the buffer in from outside the function.

>>57532581
huh

>>57532556
I mean what do you want to program?
>>57532573
https://benchmarksgame.alioth.debian.org/u64q/compare.php?lang=python3&lang2=gcc

>>57532560
Absolutely. I was a big cheerleader for Scala back when, but it's grown into an ugly halfway house with an enormous kludge of features.

>>57532604
Whatever I'll get paid to program. Hopefully nothing to do with C

>>57532556
That is a very social career path, like a professional handshaker. Unless you are super charismatic or jewish, you'll never make it. Also I doubt you can get your foot in the door. Not only are high level languages low paying (because anyone can do it), but the last person anyone would hire to write software is someone who want to "program as quickly as possible".

>>57532604
> Correlation and causality are the same thing

>>57532600
If you want a MODIFIABLE dynamic string, you should use [] instead of *.
It works the same way.
if you want a stack-allocated text buffer just create a char buffer[1024]

>>57532624
well you can do webdev, which langauges like python is perfect for. But if you want to do any real programming you will need to work with a harder language.

>>57532647
>If you want a MODIFIABLE dynamic string, you should use [] instead of *.
>It works the same way.
No it doesn't. [] is automatically (stack) allocated, malloc is dynamically allocated.
You can't do

char *my_fn(void)
{
    char s[] = "Hello world!";
    return s;
}

>>57532646
>comparing the speed of assignment of variables means that one language isn't faster then the other

>>57532644
But there's a higher chance of getting hired doing JS than there is a chance getting hired doing C. There are few uses for C developers in 99% of businesses these days. You'd have to work for a tech company that invests in its own systems software, or work doing embedded programming (fuck that shit). Meanwhile, everybody in the non techn giant sector is moving towards web dev and web apps because they're cheaper to develop and deploy.

>>57532670
If you declare that dynamic string outside of the function and pass it in as a pointer, it'll work just fine.

>>57532694
They are cheaper to develop and deploy because those jobs get outsourced.

>>57532672
>Missing the point this hard
Hideous and tedious syntax did not make a language faster

>>57532700
>that dynamic string
It's not fucking dynamic though. "Dynamic" in C means that it was allocated using malloc and friends.
It's statically sized to be the length of the string literal.
>pass it in as a pointer, it'll work just fine
You're bringing up completely irrelevant shit.

>>57528526
still java

>>57532717
I never said it did. All I am saying is C is much faster then any scripting language when it comes to performance. It just so happens that scripting languages are easier to write.

>>57532710
They're cheaper to develop and deploy because it's much faster to write code in JavaScript and HTML than C, and it's easier to deploy because everybody has a web browser on their computer, which makes your code portable across all platforms with a decent browser. The web is the future of technology. Soon, most personal computers will be like chromebooks; cheap, low processing power, and a connection to the internet.

>>57532720

char str[] = "hello world";
char *a = strdup(str);
if (!strcmp(a, str))
     printf("go fuck yourself");

>>57532758
Are you fucking retarded?
That has literally nothing to do with what's being argued about.

>>57532700
>If you declare that dynamic string outside of the function and pass it in as a pointer, it'll work just fine.
That's just automatically being allocated still though. For it to be dynamic, you need to guarantee it to be allocated not on the stack frame of the function. That's kind of the point of dynamic allocation in the first place. If you try to do that and pass the pointer with the string on the stack, it'll obviously segfault outside of that function.

>>57528441
>With imperative programming, we would have solved it by nesting three loops and then testing if the current combination satisfies a right triangle and if it has the right perimeter.
Only if you're a retard.
There are formulas for generating Pythagorean triples.

>>57532747
But that's what I said and you argued anyway, numbnuts

I am getting nudges both from my parents and from one of my professors that it might be a good idea to jump straight into a PhD after I have finished my master's degree. My parents because they think Trump might screw up the tech industry (as I see it, the decreased competition from H1Bs MIGHT work in my favor), making academia the safest choice, and my professor, noting that there's an increasing demand for computer science PhDs in academia due to the large number of incoming students, and industry sniping away all the good ones (this seems like a reasonable argument, but I understand that my professor may have some bias in this area). I have always planned to get a PhD after spending a few years in the industry to get real world experience, but I am curious whether it is even a wise move.

>>57528521
the language is haskell

>>57532962
Haskell would still be functional without them, and they are just library functions

>>57532956
>Doctor Autist Ponyfucker
It doesn't have a good ring to it.

>>57532956
are you afraid of the real world?

>>57532974
it'd still be functional, everyone would just have to implement their own map and filter functions. functional programming is about transforming data, and that's what maps and filters do

>>57532511
Haskell lost the plot the moment they took ocaml and decided to make it useless by removing all the bits which made ML convenient.

>>57533006
maps and filters are not remotely special

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How do I get started with mobile app development, /g/?

>>57530818
In case you're still here, setting it to 4 connections didn't fix it but reduced it.
It's probably that the server refuses some of the download requests because its multiple in a millisecond.

I set it back to 10 and re-download anything that has 0 bytes.

Now I just have to deal with the rare case of a thread 404ing while I'm downloading from it

>>57533037
sauce

>>57533035
yeah they are

>>57532999

Not really. I am nervous, but I want to jump straight into a career as soon as I can, especially if it's at a large enough company like Microsoft that I can settle into and not have to worry about jumping between companies every so often.

>>57533037

Learn Java and XML
Download Android Studio
Make applications, test on your phone.

>>57533114
IMO when someone sees you have a PhD in computer science with no experience, they may think you're afraid of being out in the real world, and that the skills that you may bring to the job don't match what you expect to be paid. what do i know though

>>57533129
Also there's such a thing as over qualification. PhD means that you're going to quit your job as a developer as soon as you get a better offer

>>57533168
>>57533129
To be fair, if you have anything more than a BSc, you're already highly overqualified unless you intend to work in data science.

Ruby has effectively doomed himself to being stuck in academia forever.

>>57533129

If you get a PhD, you're doing research, not regular application development. In this situation, the experience that matters is your research experience.

Though with just my master's and very little experience (just some small personal projects, no internships or jobs), I am wondering how this will affect my job prospects.

>>57533186
>Ruby will eventually be forced into using Haskell
neat 2bh

>>57533186

>if you have anything more than a BSc, you're already highly overqualified unless you intend to work in data science.

Not really. Some larger companies (Microsoft, Amazon, Google) do seem to prefer master's degrees, and that's where I'm trying to aim myself career-wise.

>>57533204

In academia, implementation language is more or less irrelevant, compared to the results.

>>57533239
>x heavily influences y
>x is irrelevant compared to y

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>know enough haskell to know that i hate normal imperative & poo languages
>don't know it well enough to use it instead of them for regular computing
it's like i'm in a weird twilight area

>>57533255
You sound like a poser desu

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>>57533239
>10 years of post-secondary education is the new bachelors

just fuck my shit up senpai

>>57533255
>muh haskell is so useful
>but i can't use it
congrants you fell for the meme

>>57533255
stupid wojak poster
you will never master haskell

>>57533249

It really depends upon the subject matter, but for many areas of computer science, any general purpose programming language will get the job done. I don't really think I have any professors who use Haskell for their own research, though I know one that loves Java, one that loves Python, a few who love C, another that uses Perl and C++ for a number of things...

>>57533302
Why would you choose to use a generally inferior general purpose language?

>>57533255
haskell is the c++ of SML

you will never know enough HASKALL. whoever claims they do is usually just mediocre github memester.

Still, though rare, haskell type monks are known to exist, who authored the very few useful haskell programs known to man (pandoc, haskell-tor...).

>>57533312
they're """"scientists"""", not programmers, they don't need to use the best language, just whichever language they know/like

>>57533312

Because it's not Haskell.

I could honestly see myself seeing Ruby in academic research for a number of purposes. Or maybe if it was systems-related, C, C++, or Rust.

>>57532511
Type inference is pretty much only good for things like generics and variable binding, but it's a godsend there. A good rule of thumb is that all top-level expressions should be annotated with their type.

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>>57533349
>Ruby
>the language
>going anywhere

LOL

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Can someone give me a description for retards of Parallel.For()?

if i'm trying to split 10,000 characters into 4 threads for manipulation, how would that work?

I'm thinking something like:

int[] numArray = new array[10000];

Parallel.For(0, 4, i =>
{
    for(int j=0; j < numArray.Length / 4 ; j++)
    {
        manipulate(numArray[j]);
    }
}

So it's saying make 4 threads, and then to split the array evenly among the threads.
Is this even somewhat close?

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New to programming and learning by myself.
I thought training at codewars would be a good idea to improve. I tried this exercise in eclipse and it worked, but it doesn't in the page. Am i not allowed to use the java libraries or something?
Sorry if this doesn't belong here.

>>57533383

Who cares? A language doesn't need to be popular to be usable.

>>57533459

I think you forgot to return persistence(result). You just called the function and threw the return value on the floor.

>>57528454
Please tell me this is a joke anon

>>57533516
Does it matter? It keeps calling itself until it has the result and then returns it all the way back to whatever called the method.

>>57533459
>>57533516
>>57533590
Sorry, forgot to add that there is a last line saying
>return num;
at the end of the method.

>>57533590

>and then returns it all the way back to whatever called the method.
Not if you don't return the value of the recursive call.

Anyways, here's how I'd implement it in Ruby:

def persistence num
  if num < 10 then 0
  else 1 + persistence(num.to_s.chars.map(&:to_i).reduce(:*))
  end
end

Ruby has an implicit return for expressions. Java does not.

being a child is loving the elegance of haskell. being an adult is realizing java makes more sense

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>>57533459
Nice code bro

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>>57533703
B-b-but it works on eclipse anon.
9*8*4*9*8*4 = 82944
8*2*9*4*4 = 2304
2*3*0*4 = 0

>>57533794
you can get rid of that last else

>>57533808
Done, thanks.

>>57533781
I personally think using #reduce would be better for future reading. I don't know if java(?) has reduce.

Also the final if condition is wrong, someone should add a test to "251" as input.

>>57533794

Oh, I just realized num is global here. Now I know your problem. Try calling persistence multiple times. Note that it'll start giving the wrong answer after the first call.

>>57533781
Cool. You are using lambda expressions right? I haven't gotten into that.

>>57533834
Thanks anon, i see the problem now. Don't know how to solve it but i'll get it eventually.

>>57533834
non functional code makes me literally sick to my stomach in real life

>>57533459
If I was you, I would go on codingame, it has a great community and some nice contests

>>57533781
What language?

>>57533883

>don't know how to solve it
Well for starters, don't use a static variable.

>>57533934
Too late, solved it with another static variable, ha. I know it's terrible code but i'll improve.

>>57534021

>Too late
Not at all too late. Do it again. This time without using a global variable. You know it's wrong, so fix it.

>>57533919
Javascript

>>57534047
>wants a phd
>not intelligent enough to appreciate haskell

>>57534047
Yeah yeah i know, i'll try to do it better tomorrow, but it's late and i work in the morning. It's still a small victory.
Thanks a lot for the help anon.

>>57534061

Considering a PhD, but debating.
Intelligent enough to know I can get my work done just fine without Haskell.

>>57534070

Fair enough. But for the future, don't get too used to using global variables for everything. They have a purpose, and it is not for implementing basic tail recursion.

What is node.js?
What is react?
What is angular?

I just use C# for webdev i don't get all this java blabbering.

Complete C beginner here, what's a good way to handle locales? I noticed that if I input a floating number in my program and use a comma instead of a period, it doesn't work right.

>>57534140
C was made by Americans. Use periods.

>>57533703
>>57533794
>>57533781
>Not tail recursive
>String operations
>Fucks up on negative numbers
Garbage.

static int _persistence(long n, int result)
{
    if (n > -10 && n < 10)
        return result;

    long product = 1;
    for (; n != 0; n /= 10)
        product *= labs(n % 10);

    _persistence(product, result + 1);
}

int persistence(long n)
{
    return _persistence(n, 0);
}

>>57534183
Well, is there a way to at least reject commas? With strchr() maybe?

>>57534140
Call

setlocale(LC_ALL, "");

at the very start of your program.

>>57534215
Doesn't work either I'm afraid. I'll probably just make the parser very strict.

>>57534111

>What is node.js?
An implementation of the V8 Javascript engine outside of the context of a web browser, which is useful for both server side development and some general purpose programming.

>What is react?
By the looks of things, a Javascript library for handling UI shit. So, it's more relevant to you if you do front-end development.

>What is angular?
A front-end Javascript framework.

>i don't get all this java blabbering.
Javascript. Nothing to do with Java.

>>57534187

By default, Matz' Ruby Interpreter doesn't implement tail call optimization. Also, 1 + recursive_call() may not be tail recursive by definition, but many compilers/interpreters that do tail call optimization can optimize that recursive call as well. This is the case with many C compilers, though no C compiler is required to perform any tail call optimization, so you might as well use a for loop.

As for negative numbers, I did not figure that they needed to be covered, but I could just add an abs in there before the to_s.

Oh, and I used to_s since it made everything a one liner. Ruby allows me to be a lazy shit.

When is Spectrum BASIC mkaing a comeback?

>>57534187
I realised I forgot the return on the recursive call.
I originally had it structured differently, and forgot to put it in.

>>57534254
>By default, Matz' Ruby Interpreter doesn't implement tail call optimization
What is with all of those meme dynamic scripting languages that don't have TCO? Is Lua the only one of any real popularity that does it?

>>57534308

It isn't required because JRuby is a thing, and Java doesn't like TCO. The MRI does support TCO, but only if compiled as an optional extra, IIRC.

>>57534330
As always, Java ruins shit for everybody.

>take over website
>it's a node.js episode
>have hated javascript since last century and now I hear they made it so you can run it in a shell.

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>>57534308
>muh recursion
kys

>>57534443
>I'm too stupid to understand recursion

>>57534482
>i'm too stupid to understand that iteration is objectively better than recursion

new thred when

New thread: >>57534535

NEW THREAD NOW!

>>57534529
>>57534529

>>57534538
mine was first fuck off

>>57534308
>What is with all of those meme dynamic scripting languages that don't have TCO?
Fucking this.
Especially since TCO is such a trivial optimization it's a fucking no brainer to implement it: When compiling the final 'return', check previous instruction, was it a call? If so, forget the 'return' and replace the call to a jump.

>>57528838
boosting for degeneracy