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  • what type of bug causes a program to slowly use more processor power and all of a sudden go to 100%?

    - by reinier
    Hi, I was hoping to get some good ideas as to what might be causing a really nasty bug. This is a program which is transmitting data over a socket, and also receives messages back. I could explain lots more, but I don't think this will help here. I'm just searching for hypothetical problems which can cause the following behaviour: program runs processor time slowly accumulates (till around 60%) all of a sudden (could be after 30 but also after 60 seconds) the processor time shoots to 100%. the program halts completely In my syslog it always ends on one line with a memory allocation (something similar to: myArray = new byte[16384]) in the same thread. now here is the weird part: if I set the debugger anywhere...it immediately stops on that line. So just the act of setting a breakpoint, made the thread continue (it wasn't running since I saw no log output anymore) I was thinking 'deadlock' but that would not cause 100% processor power. If anything, the opposite. Also, setting a breakpoint would not cause a deadlock to end. anyone else a theoretical suggestion as to what kind of 'construct' might cause this effect? (apart from 'bad programming') ;^) thanks EDIT: I just noticed.... by setting the sendspeed slower, the problem shows itself much later than expected. I would think around the same amount of packets send...but no the amount of packets send is much higher this way before it has the same problem.

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  • Implementing Naïve Bayes algorithm in Java - Need some guidance

    - by techventure
    hello stackflow people As a School assignment i'm required to implement Naïve Bayes algorithm which i am intending to do in Java. In trying to understand how its done, i've read the book "Data Mining - Practical Machine Learning Tools and Techniques" which has a section on this topic but am still unsure on some primary points that are blocking my progress. Since i'm seeking guidance not solution in here, i'll tell you guys what i thinking in my head, what i think is the correct approach and in return ask for correction/guidance which will very much be appreciated. please note that i am an absolute beginner on Naïve Bayes algorithm, Data mining and in general programming so you might see stupid comments/calculations below: The training data set i'm given has 4 attributes/features that are numeric and normalized(in range[0 1]) using Weka (no missing values)and one nominal class(yes/no) 1) The data coming from a csv file is numeric HENCE * Given the attributes are numeric i use PDF (probability density function) formula. + To calculate the PDF in java i first separate the attributes based on whether they're in class yes or class no and hold them into different array (array class yes and array class no) + Then calculate the mean(sum of the values in row / number of values in that row) and standard divination for each of the 4 attributes (columns) of each class + Now to find PDF of a given value(n) i do (n-mean)^2/(2*SD^2), + Then to find P( yes | E) and P( no | E) i multiply the PDF value of all 4 given attributes and compare which is larger, which indicates the class it belongs to In temrs of Java, i'm using ArrayList of ArrayList and Double to store the attribute values. lastly i'm unsure how to to get new data? Should i ask for input file (like csv) or command prompt and ask for 4 values? I'll stop here for now (do have more questions) but I'm worried this won't get any responses given how long its got. I will really appreciate for those that give their time reading my problems and comment.

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  • What is the recommended coding style for PowerShell?

    - by stej
    Is there any recommended coding style how to write PowerShell scripts? It's not about how to structure the code (how many functions, if to use module, ...). It's about 'how to write the code so that it is readable'. In programming languages there are some recommended coding styles (what to indent, how to indent - spaces/tabs, where to make new line, where to put braces,...), but I haven't seen any suggestion for PowerShell. What I'm interested particularly in: How to write parameters function New-XYZItem ( [string] $ItemName , [scriptblock] $definition ) { ... (I see that it's more like 'V1' syntax) or function New-PSClass { param([string] $ClassName ,[scriptblock] $definition )... or (why to add empty attribute?) function New-PSClass { param([Parameter()][string] $ClassName ,[Parameter()][scriptblock] $definition )... or (other formatting I saw maybe in Jaykul's code) function New-PSClass { param( [Parameter()] [string] $ClassName , [Parameter()] [scriptblock] $definition )... or ..? How to write complex pipeline Get-SomeData -param1 abc -param2 xyz | % { $temp1 = $_ 1..100 | % { Process-somehow $temp1 $_ } } | % { Process-Again $_ } | Sort-Object -desc or (name of cmdlet on new line) Get-SomeData -param1 abc -param2 xyz | % { $temp1 = $_ 1..100 | % { Process-somehow $temp1 $_ } } | % { Process-Again $_ } | Sort-Object -desc | and what if there are -begin -process -end params? how to make it the most readable? Get-SomeData -param1 abc -param2 xyz | % -begin { init } -process { Process-somehow2 ... } -end { Process-somehow3 ... } | % -begin { } .... or Get-SomeData -param1 abc -param2 xyz | % ` -begin { init } ` -process { Process-somehow2 ... } ` -end { Process-somehow3 ... } | % -begin { } .... the indentitation is important here and what element is put on new line as well. I have covered only questions that come on my mind very frequently. There are some others, but I'd like to keep this SO question 'short'. Any other suggestions are welcome.

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  • Can you review my Perl rewrite of Cucumber?

    - by Evgeny
    There is a team working on acceptance testing X11 GUI application in our company, and they created a monstrous acceptance testing framework that drives the GUI as well as running scenarios. The framework is written using Perl 5, and scenario files look more like very complex Perl programs (thousands of lines long with procedural-programming style) than acceptance tests. I recently learned Ruby's Cucumber, and generally have been using Ruby for quite a lot of time. But unfortunately I can't just shove Ruby to replace Perl because the people who are writing all of this don't know Ruby and it's quite certain that they wont want "this" kind of interruption. So to bring Ruby's Cucumber a bit closer to their work, I rewrote it using Perl 5. Unfortunately I am really not a Perl programmer, and would love to get a code review and to hear suggestions from people who both know Perl and Cucumber. Hi Perl/Cucumber StackOverflow users - please help me create this "open source" attempt to re-create Cucumber for Perl! I would love to hear your comments and will accept any acceptable help. The minimal source code is here: http://github.com/kesor/p5-cucumber Thank you for your attention. For those not familiar with cucumber - please take just one small moment to take a look at this one small little page: http://wiki.github.com/aslakhellesoy/cucumber

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  • Starter question of declarative style SQLAlchemy relation()

    - by jfding
    I am quite new to SQLAlchemy, or even database programming, maybe my question is too simple. Now I have two class/table: class User(Base): __tablename__ = 'users' id = Column(Integer, primary_key=True) name = Column(String(40)) ... class Computer(Base): __tablename__ = 'comps' id = Column(Integer, primary_key=True) buyer_id = Column(None, ForeignKey('users.id')) user_id = Column(None, ForeignKey('users.id')) buyer = relation(User, backref=backref('buys', order_by=id)) user = relation(User, backref=backref('usings', order_by=id)) Of course, it cannot run. This is the backtrace: File "/Library/Python/2.6/site-packages/SQLAlchemy-0.5.8-py2.6.egg/sqlalchemy/orm/state.py", line 71, in initialize_instance fn(self, instance, args, kwargs) File "/Library/Python/2.6/site-packages/SQLAlchemy-0.5.8-py2.6.egg/sqlalchemy/orm/mapper.py", line 1829, in _event_on_init instrumenting_mapper.compile() File "/Library/Python/2.6/site-packages/SQLAlchemy-0.5.8-py2.6.egg/sqlalchemy/orm/mapper.py", line 687, in compile mapper._post_configure_properties() File "/Library/Python/2.6/site-packages/SQLAlchemy-0.5.8-py2.6.egg/sqlalchemy/orm/mapper.py", line 716, in _post_configure_properties prop.init() File "/Library/Python/2.6/site-packages/SQLAlchemy-0.5.8-py2.6.egg/sqlalchemy/orm/interfaces.py", line 408, in init self.do_init() File "/Library/Python/2.6/site-packages/SQLAlchemy-0.5.8-py2.6.egg/sqlalchemy/orm/properties.py", line 716, in do_init self._determine_joins() File "/Library/Python/2.6/site-packages/SQLAlchemy-0.5.8-py2.6.egg/sqlalchemy/orm/properties.py", line 806, in _determine_joins "many-to-many relation, 'secondaryjoin' is needed as well." % (self)) sqlalchemy.exc.ArgumentError: Could not determine join condition between parent/child tables on relation Package.maintainer. Specify a 'primaryjoin' expression. If this is a many-to-many relation, 'secondaryjoin' is needed as well. There's two foreign keys in class Computer, so the relation() callings cannot determine which one should be used. I think I must use extra arguments to specify it, right? And howto? Thanks

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  • How do I check to see if my subview is being touched?

    - by Amy
    I went through this tutorial about how to animate sprites: http://icodeblog.com/2009/07/24/iphone-programming-tutorial-animating-a-game-sprite/ I've been attempting to expand on the tutorial by trying to make Ryu animate only when he is touched. However, the touch is not even being registered and I believe it has something to do with it being a subview. Here is my code: -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{ UITouch *touch = [touches anyObject]; if([touch view] == ryuView){ NSLog(@"Touch"); } else { NSLog(@"No touch"); } } -(void) ryuAnims{ NSArray *imageArray = [[NSArray alloc] initWithObjects: [UIImage imageNamed:@"1.png"], [UIImage imageNamed:@"2.png"], [UIImage imageNamed:@"3.png"], [UIImage imageNamed:@"4.png"], [UIImage imageNamed:@"5.png"], [UIImage imageNamed:@"6.png"], [UIImage imageNamed:@"7.png"], [UIImage imageNamed:@"8.png"], [UIImage imageNamed:@"9.png"], [UIImage imageNamed:@"10.png"], [UIImage imageNamed:@"11.png"], [UIImage imageNamed:@"12.png"], nil]; ryuView.animationImages = imageArray; ryuView.animationDuration = 1.1; [ryuView startAnimating]; } -(void)viewDidLoad { [super viewDidLoad]; UIImageView *image = [[UIImageView alloc] initWithFrame: CGRectMake(100, 125, 150, 130)]; ryuView = image; ryuView.image = [UIImage imageNamed:@"1.png"]; ryuView.contentMode = UIViewContentModeBottomLeft; [self.view addSubview:ryuView]; [image release]; } This code compiles fine, however, when touching or clicking on ryu, nothing happens. I've also tried if([touch view] == ryuView.image) but that gives me this error: "Comparison of distinct Objective-C type 'struct UIImage *' and 'struct UIView *' lacks a cast." What am I doing wrong?

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  • Thread resource sharing

    - by David
    I'm struggling with multi-threaded programming... I have an application that talks to an external device via a CAN to USB module. I've got the application talking on the CAN bus just fine, but there is a requirement for the application to transmit a "heartbeat" message every second. This sounds like a perfect time to use threads, so I created a thread that wakes up every second and sends the heartbeat. The problem I'm having is sharing the CAN bus interface. The heartbeat must only be sent when the bus is idle. How do I share the resource? Here is pseudo code showing what I have so far: TMainThread { Init: CanBusApi =new TCanBusApi; MutexMain =CreateMutex( "CanBusApiMutexName" ); HeartbeatThread =new THeartbeatThread( CanBusApi ); Execution: WaitForSingleObject( MutexMain ); CanBusApi->DoSomething(); ReleaseMutex( MutexMain ); } THeartbeatThread( CanBusApi ) { Init: MutexHeart =CreateMutex( "CanBusApiMutexName" ); Execution: Sleep( 1000 ); WaitForSingleObject( MutexHeart ); CanBusApi->DoHeartBeat(); ReleaseMutex( MutexHeart ); } The problem I'm seeing is that when DoHeartBeat is called, it causes the main thread to block while waiting for MutexMain as expected, but DoHeartBeat also stops. DoHeartBeat doesn't complete until after WaitForSingleObject(MutexMain) times out in failure. Does DoHeartBeat execute in the context of the MainThread or HeartBeatThread? It seems to be executing in MainThread. What am I doing wrong? Is there a better way? Thanks, David

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  • Why are floating point values so prolific?

    - by Kibbee
    So, title says it all. Why are floating point values so prolific in computer programming. Due to problems like rounding errors, and not being able to even accurately represent numbers such as 0.1, I really can't see how they got as far as they did. I understand that the computation is faster with floating point numbers, however, I can think of only a few cases that they actually the right data type would be using. If you sat back and think about every time you used a floating point value, how many times did you say, well, some error would be ok, as long as the result was a few microseconds faster. It really makes me think because Jeff was talking about NP completeness, and how heuristics give an answer that is kind of right. And well, computers shouldn't do that. They should give you the answer that is correct. Yet we see floating point values used in many applications where they are completely not valid. What really bugs me, isn't that floating point exists, but that in many languages, there isn't even a viable alternative, non-floating point, decimal value. A lot of programmers when doing financial applications have to fall back to storing the number of cents in an integer field. Which brings with it all kinds of other problems. Why do floats continue to be so prolific, even though they can't represent the real answer, and we expect computers to be accurate? [EDIT] Just to clarify, I was talking about Base 2 floating points, and not base 10 floating points. .Net offers the Decimal data type, which is a base 10 floating point value which offers a much better representation of the numbers we deal with on a daily basis in most computer programs. I find it hard to believe that even modern languages like Java don't support base 10 floating point values, unless you want to move into the realm of things like BigDecimal, which isn't really the right answer either in a lot of situations.

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  • Nested Routes and Parameters for Rails URLs (Best Practice)

    - by viatropos
    Hey there, I have a decent understanding of RESTful urls and all the theory behind not nesting urls, but I'm still not quite sure how this looks in an enterprise application, like something like Amazon, StackOverflow, or Google... Google has urls like this: http://code.google.com/apis/ajax/ http://code.google.com/apis/maps/documentation/staticmaps/ https://www.google.com/calendar/render?tab=mc Amazon like this: http://www.amazon.com/books-used-books-textbooks/b/ref=sa_menu_bo0?ie=UTF8&node=283155&pf_rd_p=328655101&pf_rd_s=left-nav-1&pf_rd_t=101&pf_rd_i=507846&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1PK4ZKN4YWJJ9B86ANC9 http://www.amazon.com/Ruby-Programming-Language-David-Flanagan/dp/0596516177/ref=sr_1_1?ie=UTF8&s=books&qid=1258755625&sr=1-1 And StackOverflow like this: http://stackoverflow.com/users/169992/viatropos http://stackoverflow.com/questions/tagged/html http://stackoverflow.com/questions/tagged?tagnames=html&sort=newest&pagesize=15 So my question is, what is best practice in terms of creating urls for systems like these? When do you start storing parameters in the url, when don't you? These big companies don't seem to be following the rules so hotly debated in the ruby community (that you should almost never nest URLs for example), so I'm wondering how you go about implementing your own urls in larger scale projects because it seems like the idea of not nesting urls breaks down at anything larger than a blog. Any tips?

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  • Extract known pattern substring from NSString (without regex)

    - by d11wtq
    I'm really tempted to drop RegexKit (or my own libpcre wrapper) into my project in order to do this, but before I do that I want to know how Cocoa developers manage to do half of this basic stuff without really convoluted code or without linking with RegexKit or another regular expression library. I find it gobsmacking that Cocoa does not include any regular expression matching features. I've so accustomed to using regular expressions for all kinds of things that I'm lost without them. I can do what I need without them, but the code would be rather convoluted. So, Cocoa devs, I ask you, what's the "Cocoa way" to do this... The problem is an everyday problem in programming as far as I'm concerned. Cocoa must have ways of doing this with the built-in features. Note that the position of the elements I want to match changes, and sometimes "quotes" are present. Whitespace is variable. Take the following strings: Content-Type: application/xml; charset=utf-8 Content-Type: text/html; charset="iso-8859-1" Content-Type: text/plain; charset=us-ascii Content-Type: text/plain; name="example.txt"; charset=utf-8 From all of these strings, how would you go about determining the mime type (e.g. text/plain) and the charset (e.g. utf-8) using just the built-in Cocoa classes? I'd end up performing a series of -rangeOfString: and substring calls, with conditional checks to deal with the optional quotes etc. Is there a way to do this with NSScanner? The NSScanner class seems to have a pretty naive API to me. Something like C's sscanf() that works for NSString objects would be an ideal fit. Most of my string parsing needs are simple such as this example so maybe regular expressions, while I'm accustomed to them, are overkill?

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  • Finding perfect numbers in C# (optimization)

    - by paradox
    I coded up a program in C# to find perfect numbers within a certain range as part of a programming challenge . However, I realized it is very slow when calculating perfect numbers upwards of 10000. Are there any methods of optimization that exist for finding perfect numbers? My code is as follows: using System; using System.Collections.Generic; using System.Linq; namespace ConsoleTest { class Program { public static List<int> FindDivisors(int inputNo) { List<int> Divisors = new List<int>(); for (int i = 1; i<inputNo; i++) { if (inputNo%i==0) Divisors.Add(i); } return Divisors; } public static void Main(string[] args) { const int limit = 100000; List<int> PerfectNumbers = new List<int>(); List<int> Divisors=new List<int>(); for (int i=1; i<limit; i++) { Divisors = FindDivisors(i); if (i==Divisors.Sum()) PerfectNumbers.Add(i); } Console.Write("Output ="); for (int i=0; i<PerfectNumbers.Count; i++) { Console.Write(" {0} ",PerfectNumbers[i]); } Console.Write("\n\n\nPress any key to continue . . . "); Console.ReadKey(true); } } }

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  • How to handle One View with multiple ViewModel and fire different Commands

    - by Naresh
    Hi All, I have senario in which one view and view has binding with multiple ViewModel. Eg. One View displaying Phone Detail and ViewModel as per bellow: Phone basic features- PhoneViewModel, Phone Price Detail- PhoneSubscriptionViewModel, Phone Accessories- PhoneAccessoryViewModel For general properties- PhoneDetailViewModel I have placed View's general properties to PhoneViewModel.Now senario is like this: By default View displays Phone Basic feaures which is bind with ObservationCollection of PhoneViewModel. My view have button - 'View Accessories', onclick of this button one popup screen- in my design I have display/hide Grid and bind it with ObservationCollection of PhoneAccessoryViewModel. Now problem begins- Accessory List also have button 'View Detail' onclick I have to open one popup screen, here also I had placed one Grid and Visible/Hide it. I have bind 'ViewAccessoryDetailCommand' command to 'View Detail' button. And on command execution one function fires and set property which Visible the Popup screen. Using such programming command fires, function calls but the property change not raises and so my view does not display popup. Summary: One View-- ViewModel1--Grid Bind view ViewModel2 --Grid Have Button and Onclick display new Grid which binded with ViewModel3-this Command fires but property not raises. I think there is some problem in my methodology, Please, give your suggetions.

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  • JMS equivalent in .Net

    - by rauts
    Hi All, I am trying to make an common abstract interface over the messaging infrastructure in our company. The design goal is to 2 fold. 1 is to hide the complexity of programming from the developers (i know its not very complex but still simplify it further) and 2 is to make the developers independent of the vendor specific messaging infrastructure (i.e. it can be MQSeries or EMS or MSMQ). The very common option is using the WCF layer over the messaging infrastructure. Use the MQSeries Custom channel for WCF or use EMS custom channle for WCF. But both are ruled out due to lack of proper version of MQSeries and EMS. Can someone please suggest what are the possible solutions to this problem. One which i can think of the to have a custom wrapper like JMS. Has anyone ever tried something similar before. Any help would be fantastic. by the way, i am trying to create this wrapper in C# 3.5. Regards

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  • Which Computer Organization & Architecture book is good for me?

    - by claws
    I'm always interested in learning the inner working of things. I started with C programming and then learnt Operating systems (from stallings) and then linkers & loaders and then assembly language after reading these now I want to go into little more depth. Computer Architecture. I feel that makes everything clear. As per SO archives these are the two good books: Computer Architecture: A Quantitative Approach, 4th Edition Computer Organization and Design, Fourth Edition, ~ David A. Patterson, John L. Hennessy But I've browsed through the contents of these books and found that they don't exactly meet my needs. I want to learn more about caches, Memory Management Unit , mapping b/w virtual memory & physical memory I'm no way interested in other ISAs like MIPS etc.. I'm IA32 and X86-64 fan and I want to stick to it. I'm not a hardware developer I don't want to details like circuit diagrams or How is L1, L2 & L3 caches are implemented? I want to know the parallel processing technologies like HyperThreading at the architecture level but again I don't want to design them. I liked the table of Contents of - Computer Architecture: A Quantitative Approach, 4th Edition but Quantitave Approach? Seriously?? I want to know the details of current technologies and I dont want to spend reading 200 pages of outdated old technologies ( I experienced this while learning ASM}

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  • JAVA Regular Expression Errors

    - by Berkay
    I'm working on a simply password strength checker and i can not success applying regular expressions. In different resources different kinds of regular expressions are defined. i also find javascript regular expressions but had some problems to adapt. First, these are the regular expressions i need for JAVA: at least one lower case letter at least one upper case letter at least one number at least three numbers at least one special character at least two special characters both letters and numbers both upper and lower case letters, numbers, and special characters My goal is not being a regular expression expert i just want to use the parts i need.If you direct me good tutorials which discusses above for java, will be appreciated. Second, in this link some of them are mentioned but i'm getting problems to apply them. here does not catch the lower case letter (my pass: A5677a) if (passwd.matches("(?=.*[a-z])")) // [verified] at least one lower case letter {Score = Score+5;} Also here i'm getting error : illegal escape character. if (passwd.matches("(?=.*\d)")) // [verified] at least one number Finally, are these expressions all different in different kind of programming or script languages?

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  • How to not persist NSManagedObjects retrieved from NSManagedObjectContext

    - by RickiG
    Hi I parse an xml file containing books, for each new node I go: Book *book = (Book*)[NSEntityDescription insertNewObjectForEntityForName:@"Book" inManagedObjectContext:managedObjectContext]; To obtain an NSManagedObject of my Core Data Book Entity, I then proceed to populate the managed Book object with data, add it to an array, rinse, repeat. When I am done, I present the list of books to the user. I have not yet executed the save: NSError *error; if (![managedObjectContext save:&error]) { NSLog(@"%@", [error domain]); } The user now selects one of the books, this one I would like to persist, but only this one, all the other books are of no interest to me any more. The Book Entity does not have/or is part of any relationships. It is just a "single" Entity. If I pull the "save lever" every Book object will be persisted and I will have to delete everything but my desired one. How would I get around this challenge, I can't really seem to find that particular use-case in the Core Data Programming Guide, which sort of also bugs me a bit, am I going against best practice here? Thanks for any help given.

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  • Compiling cpp code in netbeans produce errors, how to solve it ?

    - by Rupertt Wind
    i use the netbeans with MinGW and MYSY make /debugger but when i compile a basic cpp code in it and run it it produces two erorrs this is the code runned and the output![alt text][1] box #include <iostream> void main() { cout << "Hello World!" << endl; cout << "Welcome to C++ Programming" << endl; } output is /usr/bin/make -f nbproject/Makefile-Debug.mk SUBPROJECTS= .build-conf make[1]: Entering directory `/d/Users/Home/Documents/NetBeansProjects/newApp' /usr/bin/make -f nbproject/Makefile-Debug.mk dist/Debug/MinGW-Windows/newapp.exe make[2]: Entering directory `/d/Users/Home/Documents/NetBeansProjects/newApp' mkdir -p dist/Debug/MinGW-Windows g++.exe -o dist/Debug/MinGW-Windows/newapp build/Debug/MinGW-Windows/newmain.o build/Debug/MinGW-Windows/newfile.o build/Debug/MinGW-Windows/main.o build/Debug/MinGW-Windows/newfile.o: In function `main': D:/Users/Home/Documents/NetBeansProjects/newApp/newfile.cpp:5: multiple definition of `main' build/Debug/MinGW-Windows/newmain.o:D:/Users/Home/Documents/NetBeansProjects/newApp/newmain.c:15: first defined here build/Debug/MinGW-Windows/main.o: In function `main': D:/Users/Home/Documents/NetBeansProjects/newApp/main.cpp:13: multiple definition of `main' build/Debug/MinGW-Windows/newmain.o:D:/Users/Home/Documents/NetBeansProjects/newApp/newmain.c:15: first defined here collect2: ld returned 1 exit status make[2]: *** [dist/Debug/MinGW-Windows/newapp.exe] Error 1 make[2]: Leaving directory `/d/Users/Home/Documents/NetBeansProjects/newApp' make[1]: *** [.build-conf] Error 2 make[1]: Leaving directory `/d/Users/Home/Documents/NetBeansProjects/newApp' make: *** [.build-impl] Error 2 BUILD FAILED (exit value 2, total time: 1s) how can i solve this ?

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  • Python for a hobbyist programmer ( a few questions)

    - by Matt
    I'm a hobbyist programmer (only in TI-Basic before now), and after much, much, much debating with myself, I've decided to learn Python. I don't have a ton of free time to teach myself a hundred languages and all programming I do will be for personal use or for distributing to people who need them, so I decided that I needed one good, strong language to be good at. My questions: Is python powerful enough to handle most things that a typical programmer might do in his off-time? I have in mind things like complex stat generators based on user input for tabletop games, making small games, automate install processes, and build interactive websites, but probably a hundred things along those lines Does python handle networking tasks fairly well? Can python source be obscufated (mispelled I think), or is it going to be open-source by nature? The reason I ask this is because if I make something cool and distribute it, I don't want some idiot script kiddie to edit his own name in and say he wrote it And how popular is python, compared to other languages. Ideally, my language would be good and useful with help found online without extreme difficulty, but not so common that every idiot with computer knows python. I like the idea of knowing a slightly obscure language. Thanks a ton for any help you can provide.

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  • Python: speed up removal of every n-th element from list.

    - by ChristopheD
    I'm trying to solve this programming riddle and althought the solution (see code below) works correct, it is too slow for succesful submission. Any pointers as how to make this run faster? (removal of every n-th element from a list)? Or suggestions for a better algorithm to calculate the same; seems I can't think of anything else then brute-force for now... Basically the task at hand is: GIVEN: L = [2,3,4,5,6,7,8,9,10,11,........] 1. Take the first remaining item in list L (in the general case 'n'). Move it to the 'lucky number list'. Then drop every 'n-th' item from the list. 2. Repeat 1 TASK: Calculate the n-th number from the 'lucky number list' ( 1 <= n <= 3000) My current code (it calculates the 3000 first lucky numbers in about a second on my machine - but unfortunately too slow): """ SPOJ Problem Set (classical) 1798. Assistance Required URL: http://www.spoj.pl/problems/ASSIST/ """ sieve = range(3, 33900, 2) luckynumbers = [2] while True: wanted_n = input() if wanted_n == 0: break while len(luckynumbers) < wanted_n: item = sieve[0] luckynumbers.append(item) items_to_delete = set(sieve[::item]) sieve = filter(lambda x: x not in items_to_delete, sieve) print luckynumbers[wanted_n-1]

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  • Java and tomcat vs ASP.NET and IIS

    - by Mark Cooper
    Until recently I'd considered myself to be a pretty good web programmer (coming up for 10yrs commercial experience on a variety of e-commerce, static and enterprise applications). I'm self taught and have always used the Microsoft product stack (ASP, ASP.NET)... My applications are always functional, relatively bug free, but have never been lightening quick. As a frequent web user I always found this to be the norm... how fast are the websites from the big tech players (eBay, Facebook, Microsoft, IBM, Dell, Telerik etc etc) - in truth none are particularly fast. I always attributed this to "the way things are with web apps"... ...then I cam across a product called Jira from atlasian and this has stopped me in my tracks... This application is fast, and I mean blindingly fast.. too fast to time the switches between pages, fully live content, lots of images and data and cross references etc etc... I run this on an intranet, with a large application DB, and this is running on a very normal server (single processor, SATA HDD, 8GB RAM). Am I missing something?? Are my programming techniques that bad?? I am wondering if this speed gain is down to it being written in Java and running on Tomcat. Does anyone have any benchmarks to compare JSP / ASP or Tomcat / IIS??? Thanks, Mark NOTE: this isn't a blatant plug for Jira. I don't work for them or have any affiliation to them... but I would like to be able to write applications like them :)

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  • Visual Studio Conversion Suite

    - by KingPop
    I have this as my conversion program for the "Length", how can I do it the simpliest way instead of keeping the if, elseif, else too much, i do not have much experience and trying to improve my programming skills on visual studio 2008. Basically, I get annoyed with the formulas because I don't know if it is right, I use google but doesn't help because i don't know how to get it right when the program converts from type to type. Public Class Form2 Dim Metres As Integer Dim Centimetres As Integer Dim Inches As Integer Dim Feet As Integer Dim Total As Integer Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load ErrorMsg.Hide() End Sub Private Sub btnConvert_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnConvert.Click Metres = 1 Centimetres = 0.01 Inches = 0.0254 Feet = 0.3048 txtTo.Text = 0 If txtFrom.Text <> "" Then If IsNumeric(txtFrom.Text) And IsNumeric(txtTo.Text) Then If cbFrom.Text = "Metres" And cbTo.Text = "Centimetres" Then Total = txtFrom.Text * Metres txtTo.Text = Total ElseIf cbFrom.Text = "Metres" And cbTo.Text = "Inches" Then Total = txtFrom.Text * 100 txtTo.Text = Total ElseIf cbFrom.Text = "Metres" And cbTo.Text = "Feet" Then ElseIf cbFrom.Text = "Centimetres" And cbTo.Text = "Metres" Then ElseIf cbFrom.Text = "Centimetres" And cbTo.Text = "Inches" Then ElseIf cbFrom.Text = "Centimetres" And cbTo.Text = "Feet" Then ElseIf cbFrom.Text = "Inches" And cbTo.Text = "Metres" Then ElseIf cbFrom.Text = "Inches" And cbTo.Text = "Centimetres" Then ElseIf cbFrom.Text = "Inches" And cbTo.Text = "Feet" Then ElseIf cbFrom.Text = "Feet" And cbTo.Text = "Metres" Then ElseIf cbFrom.Text = "Feet" And cbTo.Text = "Centimetres" Then ElseIf cbFrom.Text = "Feet" And cbTo.Text = "Inches" Then End If End If End If End Sub End Class This is the source for what I have done at the moment.

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  • NPTL Default Stack Size Problem

    - by eyazici
    Hello, I am developing a multithread modular application using C programming language and NPTL 2.6. For each plugin, a POSIX thread is created. The problem is each thread has its own stack area, since default stack size depends on user's choice, this may results in huge memory consumption in some cases. To prevent unnecessary memory usage I used something similar to this to change stack size before creating each thread: pthread_attr_t attr; pthread_attr_init (&attr); pthread_attr_getstacksize(&attr, &st1); if(pthread_attr_setstacksize (&attr, MODULE_THREAD_SIZE) != 0) perror("Stack ERR"); pthread_attr_getstacksize(&attr, &st2); printf("OLD:%d, NEW:%d - MIN: %d\n", st1, st2, PTHREAD_STACK_MIN); pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); /* "this" is static data structure that stores plugin related data */ pthread_create(&this->runner, &attr, (void *)(void *)this->run, NULL); EDIT I: pthread_create() section added. This did not work work as I expected, the stack size reported by pthread_attr_getstacksize() is changed but total memory usage of the application (from ps/top/pmap output) did not changed: OLD:10485760, NEW:65536 - MIN: 16384 When I use ulimit -s MY_STACK_SIZE_LIMIT before starting application I achieve the expected result. My questions are: 1-) Is there any portable(between UNIX variants) way to change (default)thread stack size after starting application(before creating thread of course)? 2-) Is it possible to use same stack area for every thread? 3-) Is it possible completely disable stack for threads without much pain?

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  • How to connect to a SOAP webServices with Android

    - by dom4
    Hi everyone,I'm programming an application who must send coordinate and request to a WebServices this is my code: private String SOAP_ACTION = "getAllPositions"; private String METHOD_NAME = "getAllPositions"; private String NAMESPACE = "http://session/"; private static final String URL ="http://192.41.218.56:8080/WSGeoEAR-WSGeoServer/NavFinderBean?WSDL"; /** Called when the activity is first created. */ @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); setContentView(R.layout.main); SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME); request.addProperty("idUtente",1); SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11); envelope.dotNet = true; envelope.setOutputSoapObject(request); AndroidHttpTransport androidHttpTransport = new AndroidHttpTransport(URL); androidHttpTransport.setXmlVersionTag("<?xml version=\"1.0\" encoding=\"UTF-8\"?>"); androidHttpTransport.debug = true; try{ androidHttpTransport.call(SOAP_ACTION, envelope); SoapObject resultsRequestSOAP = (SoapObject) envelope.bodyIn; ArrayList<position> resultData = (ArrayList<position>)resultsRequestSOAP.getProperty("getAllPositionsResponse"); for(position p : resultData) { ((TextView)findViewById(R.id.lblStatus)).setText(p.getAllInformation()); } } catch(Exception E) { ((TextView)findViewById(R.id.lblStatus)).setText("ERROR:" + E.getClass().getName() + ": " + E.getMessage()); } } } I've also create a class position. It doesn't work,can someone help me?Thanks

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  • DirectX Desktop

    - by Jonathan
    Hi. I'd like to make an animated desktop background for Windows 7 using DirectX. I'm using C#, SlimDX and a couple of P/Invoke imports of Windows API functions. I'm not brilliant with native Windows programming, but I've had a poke around online and I believe what I need to do is either: 1) Find the handle of the window containing the dekstop wallpaper, hook it up to a DirectX device and draw into it. 2) Make a new output window, and insert it above the desktop wallpaper but below the desktop icons. I've tried both these, but neither seems to work. If I navigate the Window heirarchy starting from the handle returned by GetDesktopWindow(), I can go Desktop - WorkerW - SHELLDLL_DefView - SysListView32. If I hook up a DirectX device to this handle, I can draw over the entire desktop, but it also covers the icons. If I create a Windows form, set its parent to SHELLDLL_DefView using SetParent() and then use SetWindowPos to play with its Z-order I can only seem to get it to go either behind the desktop wallpaper or in front of the desktop + icons. It looks as though the desktop wallpaper is background to the folder view containing the icons, and therefore what I am trying to do cannot work. The only solution then would be to not use the desktop for icons, or to find some alternative, e.g. overwriting the desktop then overlaying a transparent window containing a view of the contents of some folder. Does anyone have any idea of what I should be doing, or even whether what I want to do is possible? It seems you can draw to the desktop background using the GDI (as I believe the wxSnow program does), and I've seen something similar to what I want done by VLC Media Player under Windows XP with its DirectX wallpaper mode (interestingly, I can't seem to get this option enabled on my system). Thanks!

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  • Computer science textbooks

    - by Barrett Conrad
    I would like to try the book question a little bit differently. My goal is to know what the community thinks are the quintessential computer science textbooks. <beginsadstory>I lost all of my computer science and math books from college in Hurricane Katrina in 2005. I greatly miss having my familiar tomes to refer to when topics and problems come up, so I am looking to rebuild my library.<endsadstory> What are your recommendations for the best examples of academic caliber books for the field of computer science and its associated mathematics? I am looking for books on subjects like computational theory, programming languages, compilers, operating systems, algorithms and so on. Don't limit your suggestions to your textbooks only. If there is a book you have read that covers computer science or a related math in a formal way, but is not strictly a textbook, I would be love to hear about them as well. Finally, for the sake of creating a good reference for all of us, may I suggest posting one book per answer so they can be rated individually.

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