The Thread for Programming

[WhattayaBrian]

neat

http://www.codingame.com/games

ppl keep linking me to this

it seems fun

Oh wow this is cool.

I need to find time to play it.

[lukaramu]

neat

http://www.codingame.com/games

ppl keep linking me to this

it seems fun

Oh wow this is cool.

I need to find time to play it.

Yep this is cool!!!

[docopoper]

neat

http://www.codingame.com/games

ppl keep linking me to this

it seems fun

Oh wow this is cool.

I need to find time to play it.

Yep this is cool!!!

This is indeed cool.

[WhattayaBrian]

Without looking at it too deeply, you effectively need to solve this problem:

O = optional goal
R = required goal

O + R > R

In order to do this in an interesting way, you might need more constraints in your system, perhaps things that have negative weights: O + R is better, but it takes more time, and longer times affect your "score" negatively. Or the lumberjack can work during the rain, but then he gets sick and that makes him work at a slower rate.

Once you have your list of goals, you would A* through all the permutations of the goals (R only, O then R, R then O) and see which one grants you the highest score at the end. You then need to determine how often you update your logic--every frame? Only when certain events happen?

Or something like that.

[Ashan]

[lukaramu]

I think that's the kind of thing that's only really cool if you're the one doing it, and if you're not just watching a video of someone doing it<sup>1

1</sup>those little movements most likely caused by natural head movements are driving me insane and making my headache a little bit worse tbh

[docopoper]

That looks quite fun.

[devil†zukin]

A* search pretties - here's a debug screen showing the order it searched the graph, fading from green to red



here's what happens when you forget to terminate the search, it walks immediately to the end and then decides to search the whole graph anyway (and I didn't even notice until it got slow since it still worked)



(here's what it's meant to look like for comparison)

[Ashan]

My computer labs are so weird.

So, the lab has like 20 people in it, and the lab instructed explains some stuff, demos some things on the projector, and then you go to the university website and you can find the assignments with the instructions on there. The assignments have been pretty easy so far, but when you finish them the instructor refuses to let you just show him your code and run it for him. You have to make a screenshot of the code and the output, and then show him the screenshot. It just wastes time for no reason.

[docopoper]

It just wastes time for no reason.

Sounds like college to me. xP I've had to do that screenshot thing too.

In fact if we are doing these sorts of horror stories then in first year we had a really crappy web development lecturer (according to the year before us she forgot how to do a line break in class and honestly I wouldn't put it past her). But yeah - for our assignment she made us code a website and then print out all the HTML and hand it in to her as well as submitting it online. Like seriously - that was like 45 pages of HTML!

[Ashan]

We get marked in them so I don't really have the option to not go.

[ntfwc]

I just finished a decompression cache compatible with Linux systems:

https://github.com/ntfwc/decompression_cache

I designed it so I could increase the efficiency of decompressing games in archives on-the-fly. But it is general and could be applied to other things. Someone might find it useful.

[Ashan]

I was thinking back to an old video I saw on sorting algorithms a while back that I found super satisfying to watch:



And I did my best to do a sort thing like that in C++.
http://pastebin.com/RxVpwTEr

So yeah. I made it limited to numbers between 0 and 99 for the sake of formatting in the printArray function. I don't know if there's a better way to format with simple console output but whatever.

I wanted to make a swap() function as well but I didn't know how. I managed to do it with a function swap(int x, int y) that just took variables by using pointers, but I didn't know how to do it with members of an array cause pointers work differently with arrays or something.

[WhattayaBrian]

Well, there are two basic ways you could implement a swap.

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void swap(int & a, int & b)
{
	int temp = a;
	a = b;
	b = temp;
}

You could use this very simply:

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swap(array[index], array[index + 1]);

You could also do:

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void swap(int * a, int * b)
{
	int temp = *a;
	*a = *b;
	*b = temp;
}

Which would be used like:

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swap(&array[index], &array[index + 1]);

or

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swap(array + index, array + index + 1);

using pointer arithmetic (technically all of these examples use pointer arithmetic, some just hide it better than others).

[Ashan]

Oh, it worked.
I could have sworn I did the exact same thing yesterday (with the first one) and it would work when I put 2 int variables in, but not when I put 2 ints that were part of an array.

Thanks!

edit: oh, also, my IDE was king of throwing a fit that I had

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srand(time(0));

From what I could tell from the caution message, time(0) gives a long value, and srand() wants an int so it was coercing the value, so I casted it

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srand(int(time(0)));

and that seemed to fix it.
Is there a better way I should be fixing it?

[Ashan]

After waiting 2+ weeks for my first assignment to get marked, I finally asked my prof about it and he said they were supposed to be marked already. So he told met to email him my name and student number and he'd figure out what's going on, and I guess nobody was assigned to be marking me or something so nobody did.

I finally did get it marked though, and I lost 10 marks out of 80 because:

(-10) - Doesn't use constants. Conversion factors should be as const

And I looked back in the assignment, and it does say

Declare all variables and constants as data type double.

so... I guess I made a mistake? It didn't really say I had to use constants, it just said make sure constants are doubles.

After the deadline, the prof posted an example solution on the website, and he basically did all of the math in the main function, but the way I did it was I created functions that converted to different units (you can see my submitted code here so I didn't really have a reason to declare constants.
Unless, they would have rather I made functions like

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double tonsToPounds(double x){
    const double TONS_TO_POUNDS = x * 2000;
    return TONS_TO_POUNDS;
}

Is that safer than what I did? I can kind of see it in the context of "if someone else was modifying your code, you want to make sure they don't mess it up, so they won't if it's a constant" but I don't know.

[Ashan]

Oops, I meant to have const double in that bit of code there. That was my mistake. Edited now.

[Ashan]

Don't judge me

[WhattayaBrian]

Well, there's this concept called a "magic number" in programming. A magic number is, more or less, a number without a name. Magic numbers are bad for maintainability, because no matter how clear they are to you as the person who originally wrote them, someone, somewhere down the line, will be confused.

It's true that putting them in a function makes it clearer, but it's still really good practice to name all your magic numbers. And, if you're going to give them a name anyway, you might as well make it const.

[Ashan]

no im being sincere that was good

Ahhh, sorry. I read your post in a sarcastic tone. (Relevant)
I wouldn't have been surprised if I did something silly. If you recall a while back, I did that "4 is the magic number" program in Java, and in my original draft I made an object in another class just for storing number to word conversions. I didn't really understand objects; I knew how to use them, but not so much what they're typically used for. I understand them a bit more now, but I still don't really know what point I'm at in understanding when you should do certain things, or when it's just wasting time and making simple things more awkward.
Obviously, learning this stuff comes with time and I'm already learning some of this stuff, but you could convince me at any point in any code I write that there's a better way to do it, so I'm all ears!

you should program something more interesting though

sign up to that thing i posted on the last page and get ue4 and put your c++ to use

Yeah, that's why outside of my class I've been working on some basics, like, more recently, that sorting algorithm for an array. I'm still kind of intimidated with stuff like UE because I've never done anything like it before. I suppose you just gotta jump in at some point, but the whole thing still feels kind of daunting from my perspective. I'll give it a shot sometime soon though!

stuff and things

Yeah, your explanation is kind of what I had in mind. I suppose writing out things in plain English will pretty much always make things easier for other people in the long run. I'll keep that in mind, thanks!

[Ashan]

I'm not sure how much of the fundamentals I know is the thing.
When I started off learning C++, I was watching TheNewBoston's tutorials and I still haven't finished that, so I'll probably continue from that series before going on.

Or you know, I could try reading from the $60 beat up book I got for this class and haven't touched once but WHO READS? NERDS, THATS WHO

[Ashan]

lol textbooks for classes i never bothered buying any of them and i'm glad i didn't

Yeah, this might be my last time doing so.

So far I've had:
English:

• Some kind of handbook for formatting essays and MLA guidelines and whatnot. Used it once for an essay but it contained nothing that I couldn't have just found by Googling.
• A book called "The Wascana Anthology" which is a collection of poems and short stories and whatnot. We've had in-class discussion on one story which I've never read, but we've had so much discussion on it at this point that I know basically everything that happens in it.
• A book by Jonathan Franzen, "The Discomfort Zone". This one was just a $20 book by Franzen, and apparently we actually are going to have to be familiar with this book by the end of the year, so I'm actually reading through it in my spare time. I actually don't mind it so far, so there's that.

Calculus:

• A little ringed booklet made specifically for the course (my prof worked on it) that was around $20 I think? Never used it once.

Philosophy:

• The Art of Reasoning. Never read anything from it even once.

CompSci:

• A C++ book which like a mentioned, haven't even opened for anything other than to shove my syllabus into it. I actually don't mind having it around though, cause I might keep it anyway since I'm majoring in CompSci and all.

typing std:: before the few std functions you call is not a big deal when you get used to it and "using namespace" is really not used much in practice for good reason

the bizarre "using namespace std;" habit that introductory courses hammer into people is really not a good one

I've seen people online (stack overflow and whatnot) tend to use std:: so yeah, I was kind of wondering about that. Is there a reason it's "bad practise", other than I'm guessing you just don't use cout and whatnot in day-to-day C++ programming?
I assumed it was kind of like in Java where rather than writing

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java.util.Scanner sc = new java.util.Scanner(System.in);

you could just import it at the beginning

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import java.util.Scanner;

and the later you wouldn't have to manually type it out every time.

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Scanner sc = new Scanner(System.in);

[WhattayaBrian]

It's true, it's something to be wary of.

On a whim, I saw how many instances of "using namespace" there are in my UE3 project at work right now. Turns out there are exactly 300, which is not a large amount, and many of them are in CLR code (so who cares about quality amirite).

Still, convenience is valuable, and "JsonPrimitive" is easier to read than, say, "System.Json.JsonPrimitive" (to pull a random example from C#), especially if you're using a lot of these objects in a block of code. In that sense, I would probably find myself using a local using statement, which is confined to a scope.

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#include <iostream>

int main()
{
	{
		using namespace std;
		cout << "Yay";
	}
	cout << "This is a compile error!";
}

[Ashan]

Wow, I'd really like to try out UE if my university would fix their website!!!

[docopoper]

I'm pretty sure all you need is a valid student email address. That's all I needed.