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Thread Rules
1. This is not a "do my homework for me" thread. If you have specific questions, ask, but don't post an assignment or homework problem and expect an exact solution.
2. No recruiting for your cockamamie projects (you won't replace facebook with 3 dudes you found on the internet and $20)
3. If you can't articulate why a language is bad, don't start slinging shit about it. Just remember that nothing is worse than making CSS IE6 compatible.
4. Use [code] tags to format code blocks. |
On November 10 2012 22:45 myzael wrote:Show nested quote +On November 10 2012 21:34 Recognizable wrote:My first code  from datetime import datetime
now=datetime.now()
print (now)
current_year=now.year
current_month=now.month
current_day=now.day
hour=now.hour
minute=now.minute
second=now.second
slash="/"
print (str(current_day) + (slash) + str(current_month) + (slash) + str(current_year) +" "+ str(hour) + ":" + str(minute) + ":" +str(second)) This is what you'll get: 10/11/2012 13:30:48 I'm going through the python codeacademy classes right now. Does anyone have a useful site for an overview of the very basics of programming? IE: One that explains what a variable is and lists the types of variables. Codeacademy does this aswell but it doesn't give you a nice overview. You might want to get used to the following formatting, it is both clearer and more widespread: print "%s/%s/%s %s:%s:%s" % (str(current_day), str(current_month), str(current_year), str(hour), str(minute), str(second)) Also, you don't need that many brackets. Furthermore, not trying to be rude or smartass, but python is about clarity IMO. from datetime import datetime
print datetime.now().strftime("%d/%m/%Y %H:%M:%S") As for introduction. You are trying to write in python. Why not start with this: http://docs.python.org/2.7/tutorial/introduction.html ?
The codeacademy site suggested I used concatenation. I get what you are saying with clarity, but this was given to me to figure out how to get the time, so I kinda just went along. In total I have about 1.5 hours of coding experience ^.^
now=datetime.now()
print (now)
current_year=now.year
current_month=now.month
current_day=now.day
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Well it is for you to decide what is clearer 
Also, I am not saying that you should write a whole web-app with minimal experience, it is natural to write code in a way as you do, being a beginner. I was there, too. Hell, I was much, much worse!
You should just focus on writing progressively better code. It should be as short as possible, but not at the cost of readability. That's my point of view at least.
Keep it up!
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Hey, this isn't really a programming question, but more of a computer science/programming knowledge question. Would it be a good idea to take classes on ring/group/field/coding theory (In mathematics)?
I'm wondering because I'm taking a Comp Sci degree at University, and next term I have a free class to take anything I want. I'd like to take something related to my major or that can help me build a broader knowledge base, but I literally can't fit any comp sci class into my schedule as it is, so I'm looking for other alternatives.
A couple of weeks ago, there was quite a long discussion on integer factorization, and that got me reading about different algorithms for factorization, and how it applies to cryptography, and so on. One thing I noticed, is that there was a lot of application of group/field theory to solving this problem, and it piqued my interest. Looking it up later, I saw there are multiple classes out of the Math department on the subject, and they'd actually fit my schedule. I've already taken a couple of Linear Algebra courses, so I have the pre-req's already too.
So, what I'm basically wondering, is if taking Math classes on more advanced algebra would be practically useful, or if it wouldn't really mean anything unless I went on to a PhD program or something where you deal more with theory.
Here's the course description if anyone cares:
+ Show Spoiler +Integers. Mathematical induction. Equivalence relations. Commutative rings, including the integers mod n, complex numbers and polynomials. The Chinese remainder theorem. Fields and integral domains. Euclidean domains, principal ideal domains and unique factorization. Quotient rings and homomorphisms. Construction of finite fields. Applications such as public domain encryption, Latin squares and designs, polynomial error detecting codes, and/or addition and multiplication of large integers.
After this, I could take further courses on either coding theory, or move into group/field theory.
Any advice would be appreciated. Yay, math! :p
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On November 11 2012 06:08 Mr. Wiggles wrote:Hey, this isn't really a programming question, but more of a computer science/programming knowledge question. Would it be a good idea to take classes on ring/group/field/coding theory (In mathematics)? I'm wondering because I'm taking a Comp Sci degree at University, and next term I have a free class to take anything I want. I'd like to take something related to my major or that can help me build a broader knowledge base, but I literally can't fit any comp sci class into my schedule as it is, so I'm looking for other alternatives. A couple of weeks ago, there was quite a long discussion on integer factorization, and that got me reading about different algorithms for factorization, and how it applies to cryptography, and so on. One thing I noticed, is that there was a lot of application of group/field theory to solving this problem, and it piqued my interest. Looking it up later, I saw there are multiple classes out of the Math department on the subject, and they'd actually fit my schedule. I've already taken a couple of Linear Algebra courses, so I have the pre-req's already too. So, what I'm basically wondering, is if taking Math classes on more advanced algebra would be practically useful, or if it wouldn't really mean anything unless I went on to a PhD program or something where you deal more with theory. Here's the course description if anyone cares: + Show Spoiler +Integers. Mathematical induction. Equivalence relations. Commutative rings, including the integers mod n, complex numbers and polynomials. The Chinese remainder theorem. Fields and integral domains. Euclidean domains, principal ideal domains and unique factorization. Quotient rings and homomorphisms. Construction of finite fields. Applications such as public domain encryption, Latin squares and designs, polynomial error detecting codes, and/or addition and multiplication of large integers. After this, I could take further courses on either coding theory, or move into group/field theory. Any advice would be appreciated. Yay, math! :p
Depends on what you mean by practical.
Will you really need to use what that class taught you within the next 2 years? The answer is probably no, depending on what you wanna do.
Will having that class help you find a job? Probably not.
Will the knowledge offered in class help you solve a big problem in CS? Possibly.
Is it a good idea to study something that interests you and has possible applications in your field? Yes.
Just read more on it and see if this is something you want to wager on.
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On November 11 2012 06:08 Mr. Wiggles wrote:Hey, this isn't really a programming question, but more of a computer science/programming knowledge question. Would it be a good idea to take classes on ring/group/field/coding theory (In mathematics)? I'm wondering because I'm taking a Comp Sci degree at University, and next term I have a free class to take anything I want. I'd like to take something related to my major or that can help me build a broader knowledge base, but I literally can't fit any comp sci class into my schedule as it is, so I'm looking for other alternatives. A couple of weeks ago, there was quite a long discussion on integer factorization, and that got me reading about different algorithms for factorization, and how it applies to cryptography, and so on. One thing I noticed, is that there was a lot of application of group/field theory to solving this problem, and it piqued my interest. Looking it up later, I saw there are multiple classes out of the Math department on the subject, and they'd actually fit my schedule. I've already taken a couple of Linear Algebra courses, so I have the pre-req's already too. So, what I'm basically wondering, is if taking Math classes on more advanced algebra would be practically useful, or if it wouldn't really mean anything unless I went on to a PhD program or something where you deal more with theory. Here's the course description if anyone cares: + Show Spoiler +Integers. Mathematical induction. Equivalence relations. Commutative rings, including the integers mod n, complex numbers and polynomials. The Chinese remainder theorem. Fields and integral domains. Euclidean domains, principal ideal domains and unique factorization. Quotient rings and homomorphisms. Construction of finite fields. Applications such as public domain encryption, Latin squares and designs, polynomial error detecting codes, and/or addition and multiplication of large integers. After this, I could take further courses on either coding theory, or move into group/field theory. Any advice would be appreciated. Yay, math! :p
Abstract algebra is certainly useful with its applications to number theory, cryptography, and coding theory. Abstract algebra is also useful because the ideas can be directly applied to programming and reasoning about programs.
For example, in functional programming (e.g., Haskell and Scala), certain computations can be expressed in terms of monoids (a semigroup --- a set with a binary operation over that set --- coupled with an identity element), e.g,. list concatenation, addition over integers, union over sets. We can thus write a generic program that allows us to traverse a data structure, e.g., a list or tree, and do these monoid-al operations over these data structures without duplicating code.
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Hey guys,
I'm currently in the Process of learning Java for my CS class (11th grade in Germany, dunno what it would equal to in the American school system). As I progress faster than the others, my teacher allowed me to work on a project of my choice and I chose to do a Pokemon-stlye of Game, so I informed myself a bit about how to approach a game programming-wise. I got a "working" game loop. Now I want to go on by building a simple 2D engine going, but I had no clue how to get on it, so I searched for a bit of help and found that: http://de.twitch.tv/notch/b/302823358 (The -in my perspective- interesting part starts at 42:50). That guy does exactly what I want to achieve, but I dont understand what he's doing at all. I just see crazy amounts of bitwise operations (If I'm not mistaken; those << and >> operators are used for bitwise operations, aren't they?).
Can you give me a quick outline of what he does/shoot me a link where a similar thing is explained?
Thank you 
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On November 11 2012 09:58 Watercrystal wrote:Hey guys, I'm currently in the Process of learning Java for my CS class (11th grade in Germany, dunno what it would equal to in the American school system). As I progress faster than the others, my teacher allowed me to work on a project of my choice and I chose to do a Pokemon-stlye of Game, so I informed myself a bit about how to approach a game programming-wise. I got a "working" game loop. Now I want to go on by building a simple 2D engine going, but I had no clue how to get on it, so I searched for a bit of help and found that: http://de.twitch.tv/notch/b/302823358 (The -in my perspective- interesting part starts at 42:50). That guy does exactly what I want to achieve, but I dont understand what he's doing at all. I just see crazy amounts of bitwise operations (If I'm not mistaken; those << and >> operators are used for bitwise operations, aren't they?). Can you give me a quick outline of what he does/shoot me a link where a similar thing is explained? Thank you
Hoping into Notch's livestream of him working on his Ludem Dare project is probably not a productive way to start out. You won't really get a sense of the bigger picture from watching that video alone.
If you are intent on building a simple 2D game engine, I recommend looking elsewhere than that video for a source of information. Perusing r/gamedev for beginning tutorials is a good place to start. I rarely recommend textbooks, but Rabin's Introduction to Game Development is a good starting resource for understanding how to build a game engine.
Alternatively, if you are interested in building a game (and the engine is uninteresting), you should look into frameworks such as Unity3D that will help you get your ideas off the ground without having to build everything from scratch. (Since you are talking about this in the context of intro CS, this is probably not what you want, but its good to know that these kinds of resources are out there.)
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Okay, thank you. I will check out reddit, didn't know there was a subreddit for that :D
Thank you
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Okay so, I was recently asked at a job interview to create a linked list class (either singly or doubly, doesnt matter) in C/C++ and use it to do common functions, such as insert/delete/iterate, etc.
Now once I was done this, which was pretty straightforward, the second part of the question was to do the same thing except without using the "new" or "delete" commands (or malloc/realloc if you chose C). This part completely stumped me and basically made me lose out on a job (very sad  )
Anyways, I was wondering if someone has any tips on how one would go about doing this? Thanks!!
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On November 10 2012 22:10 FFGenerations wrote:
thanks for replies, i have a better idea of what might have happened now. might have been something like, i doubleclicked the form randomly then deleted the auto code
If you spend any amount of time developing .NET, you will do this over and over again.
In some cases it knows to remove the associated event, but in some cases it doesn't. I haven't really figured out what the criteria is.
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On November 11 2012 10:32 RayzorFlash wrote:Okay so, I was recently asked at a job interview to create a linked list class (either singly or doubly, doesnt matter) in C/C++ and use it to do common functions, such as insert/delete/iterate, etc. Now once I was done this, which was pretty straightforward, the second part of the question was to do the same thing except without using the "new" or "delete" commands (or malloc/realloc if you chose C). This part completely stumped me and basically made me lose out on a job (very sad ) Anyways, I was wondering if someone has any tips on how one would go about doing this? Thanks!!
I would have asked the interviewer what he meant by that. new/malloc just allocates space on the heap, so your only recourse is to stack allocate or globally allocate a large chunk of memory and manually slice chunks out of that yourself. In essence, you would end up implementing your own heap, which may have been the point of the problem given that you started with a linked list.
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On November 11 2012 10:40 Kambing wrote:
I would have asked the interviewer what he meant by that. new/malloc just allocates space on the heap, so your only recourse is to stack allocate or globally allocate a large chunk of memory and manually slice chunks out of that yourself. In essence, you would end up implementing your own heap, which may have been the point of the problem given that you started with a linked list.
Thanks. The clarifications I received after I admitted that I was stumped did imply that this is what they were looking for. They suggested to have a pre-allocated space, which could be a linked-list itself, from which the nodes would be removed as required, have data changed to what was needed, and then inserted to the actual linked list. However, I didn't quite understand how one would go about allocating that space or creating the "unused nodes" linked list without using new. I just couldn't wrap my head around any way to CREATE the heap itself without using new. How would I go about doing this?
Also, constraints clarification: memory usage was not a constraint for the problem, but minimizing runtime was a primary concern
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On November 11 2012 10:32 RayzorFlash wrote:Okay so, I was recently asked at a job interview to create a linked list class (either singly or doubly, doesnt matter) in C/C++ and use it to do common functions, such as insert/delete/iterate, etc. Now once I was done this, which was pretty straightforward, the second part of the question was to do the same thing except without using the "new" or "delete" commands (or malloc/realloc if you chose C). This part completely stumped me and basically made me lose out on a job (very sad ) Anyways, I was wondering if someone has any tips on how one would go about doing this? Thanks!!
Sounds like he either wanted you to use memory pools from something like VirtualAlloc, or to use a pre-allocated array of nodes (if it isn't templated). There's a lot of ways to do this.
Edit:
Well you declare a global or static array. You can use a global array of characters and treat that as a byte array. Then whenever you need to grab memory for a node you can handle the memory management yourself, instead of relying on new to go ask the operating system for memory. This would have very little overhead during run-time in terms of allocation time compared to raw new or malloc calls.
If you did indeed lose the position you really should have known what new and delete are doing before you use them. If you want to be prepared for an interview write your own new and delete (memory manager), write your own STL-mimic containers, and implement sorting algorithms with them.
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4482 Posts
Hey guys, so I'm designing a software for my visual basic class. Where I need to access the database, search for the student, display on the listbox and when I click on it, it will appear the infor of that student on the next page
So on the list box, an option should be like Firstname, lastname, school, major, email. All of them as a string
Now I need to use array or some sort of method to display that item and I'm not sure how. A friend show me how to use substring for the Firstname but then since I haven't studied substring yet, I don't know the rest either.
Please help me on this, thanks.
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On November 11 2012 10:53 CecilSunkure wrote:
If you did indeed lose the position you really should have known what new and delete are doing before you use them. If you want to be prepared for an interview write your own new and delete (memory manager), write your own STL-mimic containers, and implement sorting algorithms with them.
Will do, thanks! I felt I did really well on the interview overall aside from completely blanking out on that question. I do know what new/delete do, I just couldn't think of any way to create a linked list without using them. I'm digging into using the char array and will see how that works out.
Btw, do you know some good documentation I can look over to get started on STL? I've wanted to wrap my head around that for a while, and it surprisingly wasn't covered at all in any of my university courses
Edit: Lol, wow that was stupid of me... I just implemented the static array solution in the replica code I was writing up at home, and I'm now having d'oh moment... Can't believe I screwed up on a question with such a simple solution, lol... Thanks a lot, though!!!
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On November 11 2012 11:21 RayzorFlash wrote:Show nested quote +On November 11 2012 10:53 CecilSunkure wrote:
If you did indeed lose the position you really should have known what new and delete are doing before you use them. If you want to be prepared for an interview write your own new and delete (memory manager), write your own STL-mimic containers, and implement sorting algorithms with them. Will do, thanks! I felt I did really well on the interview overall aside from completely blanking out on that question. I do know what new/delete do, I just couldn't think of any way to create a linked list without using them. I'm digging into using the char array and will see how that works out. Btw, do you know some good documentation I can look over to get started on STL? I've wanted to wrap my head around that for a while, and it surprisingly wasn't covered at all in any of my university courses
Like how to use STL? The only STL containers I've used so far is map, vector and list. I just googled std::map, std::vector and std::list.
Edit:
If you know what new and delete do already, then why were you stumped on the interview question There's an awesome article on how to make a highly optimized allocator in game engine gems 2. It uses some really interesting bit manipulation to squeeze in as much as possible to allow pages of the manager to fit in whole inside of small cache sizes.
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On November 11 2012 11:31 CecilSunkure wrote:
Like how to use STL? The only STL stuff containers I've used so far is map, vector and list. I just googled std::map, std::vector and std::list.
I've heard a couple of people say theres some stuff in STL that is really useful for implementing hash tables, and since I'm often asked about hash tables on interviews, I feel there's some merit to knowing that, and was wondering if you knew somewhere to start regarding that
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On November 11 2012 11:33 RayzorFlash wrote:Show nested quote +On November 11 2012 11:31 CecilSunkure wrote:
Like how to use STL? The only STL stuff containers I've used so far is map, vector and list. I just googled std::map, std::vector and std::list. I've heard a couple of people say theres some stuff in STL that is really useful for implementing hash tables, and since I'm often asked about hash tables on interviews, I feel there's some merit to knowing that, and was wondering if you knew somewhere to start regarding that
Can try this: http://www.randygaul.net/2012/07/01/hash-tables-introduction/
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1019 Posts
On November 10 2012 13:47 tec27 wrote:I hope you get this figured out, but I think you're really disadvantaging yourself. You've posted code for help like this pretty much every week without fail. From the thread rules: Show nested quote +2. Don't post a huge block of code and ask "what's wrong?" or I'll smack you. There's a few reasons for this rule, I think. Number one is that it makes the thread pretty noisy and irrelevant to the vast majority of readers. Number two is that it doesn't promote interesting discussion. Number three is that it prevents you from learning how to figure out your own mistakes. This is especially evident from how many times you've come back here to ask the same sorts of things. I know, the learning curve is tough, but you have to push through that if you want to *actually* figure this stuff out. I (and I'm sure a lot of other people) would appreciate it if you didn't post your homework in here every week. Homework threads are also banned on TL, I don't see why homework posts would be allowed considering that
Sorry, I didn't know such a rule existed. thanks for letting me know. I'm pretty much done with the code now after working on it for a few hours. Thanks to everyone who helped me. And I'll try not to do this too often.
someone mentioned that he wrote something long for me but that I didnt respond. I probably didn't see it so sorry about that
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I hope this belongs into this.
I have a problem in PHP. I am reading out a directory and want to sort it. So I defined and array and try to sort it by sort(), but I cannot bring it to work. My PHP time is quite some time ago, so this might be obvious.
Here is the relevant code-snippet:
+ Show Spoiler +$dir = array(); $handle = opendir("replays"); $repz = "-2"; while ($datei = readdir ($handle)) { $repz++; } closedir($handle); echo "<table width=\"100%\" cellpadding=\"0\" cellspacing=\"0\"> <tr><td align=\"center\"> <br><br><b>Content of the Replayarchive</b> </td></tr> <tr><td width=\"100%\" align=\"center\"><br>"; $verz=opendir (''.$_SERVER[DOCUMENT_ROOT].'/'.$pfad.'/.'); while ($File = readdir ($verz)) { if($File != '.' && $File != '..' && $File != '.htaccess') { $dir[] = $file; } sort($dir); echo "<table cellpadding=\"0\" cellspacing=\"0\" width=\"50%\"><tr><td align=\"left\"> "; foreach(§dir as $File){ if(is_dir($pfad."/".$File)){ if($dl_link==1){ echo "<img width=\"11\" height=\"11\" src=\"./img/$li_bild\" alt=\"\" name=\"li\"><a href=\"replays/$File\" target=\"_blank\" > $File</a>"; } else{ echo " <img width=\"11\" height=\"11\" src=\"./img/$li_bild\" alt=\"\" name=\"li\"> $File"; } echo "</td></tr></table>";} } }
Can anyone help me please? Would be REALLY nice if you could just fix it (I guess it is just a matter of ten seconds or something), but if you do not want to fix it directly please tell me what I am doing wrong
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EPT
