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  • Linux Kernel - Integer to ASCII

    - by DRX-Z
    I need to convert an integer to it's ASCII representation from within the Linux Kernel. How can I do this? I can't find any built-in conversion methods. Are there any already in the kernel or do I need to add my own?

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  • Open source project. I want to participate in something

    - by user69514
    I am a senior in Computer Science. I want to be part of some open source project. I don't know what's available out there. Can anybody guide me? I'm good with Java, not that great with C and C++, but I know both. I also know some Cincom Smalltalk. Or if anyone has something good that they're working on I could help.

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  • Assign a static function to a variable in PHP

    - by Felipe Almeida
    I would like to assign a static function to a variable so that I can send it around as a parameter. For example: class Foo{ private static function privateStaticFunction($arg1,$arg2){ //compute stuff on the args } public static function publicStaticFunction($foo,$bar){ //works $var = function(){ //do stuff }; //also works $var = function($someArg,$someArg2){ //do stuff }; //Fatal error: Undefined class constant 'privateStaticFunction' $var = self::privateStaticMethod; //same error $var = Foo::privateStaticFunction; //compiles, but errors when I try to run $var() somewhere else, as expected //Fatal error: Call to private method Foo::privateStaticMethod() from context '' $var = function(){ return Foo::privateStaticMethod(); }; } } I've tried a few more variations but none of them worked. I don't even expect this sort of functional hacking to work with PHP but hey, who knows? Is it possible to do that in PHP or will I need to come up with some hack using eval? P.S.: LawnGnome on ##php mentioned something about it being possible to do what I want using array('Foo','privateStaticMethod') but I didn't understand what he meant and I didn't press him further as he looked busy.

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  • Abort early in a fold

    - by Heptic
    What's the best way to terminate a fold early? As a simplified example, imagine I want to sum up the numbers in an Iterable, but if I encounter something I'm not expecting (say an odd number) I might want to terminate. This is a first approximation def sumEvenNumbers(nums: Iterable[Int]): Option[Int] = { nums.foldLeft (Some(0): Option[Int]) { case (None, _) => None case (Some(s), n) if n % 2 == 0 => Some(s + n) case (Some(_), _) => None } } However, this solution is pretty ugly (as in, if I did a .foreach and a return -- it'd be much cleaner and clearer) and worst of all, it traverses the entire iterable even if it encounters a non-even number. So what would be the best way to write a fold like this, that terminates early? Should I just go and write this recursively, or is there a more accepted way?

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  • Solving the problem of finding parts which work well with each other

    - by dotnetdev
    Hi, I have a database of items. They are for cars and similar parts (eg cam/pistons) work better than others in different combinations (eg one product will work well with another, while another combination of 2 parts may not). There are so many possible permutations, what solutions apply to this problem? So far, I feel that these are possible approaches (Where I have question marks, something tells me these are solutions but I am not 100% confident they are). Neural networks (?) Collection-based approach (selection of parts in a collection for cam, and likewise for pistons in another collection, all work well with each other) Business rules engine (?) What are good ways to tackle this sort of problem? Thanks

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  • How can I map a String to a function in Java?

    - by Bears will eat you
    Currently, I have a bunch of Java classes that implement a Processor interface, meaning they all have a processRequest(String key) method. The idea is that each class has a few (say, <10) member Strings, and each of those maps to a method in that class via the processRequest method, like so: class FooProcessor implements Processor { String key1 = "abc"; String key2 = "def"; String key3 = "ghi"; // and so on... String processRequest(String key) { String toReturn = null; if (key1.equals(key)) toReturn = method1(); else if (key2.equals(key)) toReturn = method2(); else if (key3.equals(key)) toReturn = method3(); // and so on... return toReturn; } String method1() { // do stuff } String method2() { // do other stuff } String method3() { // do other other stuff } // and so on... } You get the idea. This was working fine for me, but now I need a runtime-accessible mapping from key to function; not every function actually returns a String (some return void) and I need to dynamically access the return type (using reflection) of each function in each class that there's a key for. I already have a manager that knows about all the keys, but not the mapping from key to function. My first instinct was to replace this mapping using if-else statements with a Map<String, Function>, like I could do in Javascript. But, Java doesn't support first-class functions so I'm out of luck there. I could probably dig up a third-party library that lets me work with first-class functions, but I haven't seen any yet, and I doubt that I need an entire new library. I also thought of putting these String keys into an array and using reflection to invoke the methods by name, but I see two downsides to this method: My keys would have to be named the same as the method - or be named in a particular, consistent way so that it's easy to map them to the method name. This seems WAY slower than the if-else statements I have right now. Efficiency is something of a concern because these methods will tend to get called pretty frequently, and I want to minimize unnecessary overhead. TL; DR: I'm looking for a clean, minimal-overhead way to map a String to some sort of a Function object that I can invoke and call (something like) getReturnType() on. I don't especially mind using a 3rd-party library if it really fits my needs. I also don't mind using reflection, though I would strongly prefer to avoid using reflection every single time I do a method lookup - maybe using some caching strategy that combines the Map with reflection. Thoughts on a good way to get what I want? Cheers!

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  • Does a syntax for this exist? In any language?

    - by Michael
    It seems pretty common to me to have an argument, in a dynamically typed language that is either an Object or a key to lookup that object. For instance when I'm working with a database I might have a method getMyRelatedStuff(person) All I really need to lookup the related stuff is the id of the person so my method could look like this in python: def getMyRelatedStuff(person_or_id): id = person_or_id.id if isinstance(person,User) else person_or_id #do some lookup Or going the other direction: def someFileStuff(file_or_name): file = file_or_name if hasattr(file,'write') else open(file_or_name)

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  • How to determine IP used by client connecting to INADDR_ANY listener socket in C

    - by codebox_rob
    I have a network server application written in C, the listener is bound using INADDR_ANY so it can accept connections via any of the IP addresses of the host on which it is installed. I need to determine which of the server's IP addresses the client used when establishing its connection - actually I just need to know whether they connected via the loopback address 127.0.0.1 or not. Partial code sample as follows (I can post the whole thing if it helps): static struct sockaddr_in serverAddress; serverAddress.sin_family = AF_INET; serverAddress.sin_addr.s_addr = INADDR_ANY; serverAddress.sin_port = htons(port); bind(listener, (struct sockaddr *) &serverAddress, sizeof(serverAddress)); listen(listener, CONNECTION_BACKLOG); SOCKET socketfd; static struct sockaddr_in clientAddress; ... socketfd = accept(listener, (struct sockaddr *) &clientAddress, &length);

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  • an error "variable of field declared void"

    - by lego69
    I have this code: header - test.h Inside header I have some class Z and definitions of two functions test and test2 I call function test2 from test void test2(Z z, Z const *za); this is implementation of the function: void test2(Z z, Z const *za){ int i = z; //this row works cout << i << endl; } I call it from test: test2(z1, za1); // za1 is pinter to object and z1 is some object but in my header I receive an 3 errors: Multiple markers at this line - initializer expression list treated as compound expression - `A' was not declared in this scope - variable or field `quiz2' declared void can somebody please explain why? thanks in advance

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  • Does using functional languages help against computing values repeatedly?

    - by sharptooth
    Consider a function f(x,y): f(x,0) = x*x; f(0,y) = y*(y + 1); f(x,y) = f(x,y-1) + f(x-1,y); If one tries to implement that recursively in some language like C++ he will encounter a problem. Suppose the function is first called with x = x0 and y = y0. Then for any pair (x,y) where 0 <= x < x0 and 0 <= y < y0 the intermediate values will be computed multiple times - recursive calls will form a huge tree in which multiple leaves will in fact contain the same pairs (x,y). For pairs (x,y) where x and y are both close to 0 values will be computed numerous times. For instance, I tested a similar function implemented in C++ - for x=20 and y=20 its computation takes about 4 hours (yes, four Earth hours!). Obviously the implementation can be rewritten in such way that repeated computation doesn't occur - either iteratively or with a cache table. The question is: will functional languages perform any better and avoid repeated computations when implementing a function like above recursively?

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  • After C++ - Python or Java?

    - by carleeto
    I'm fast approaching the point in my coding where I would like to quickly write object oriented code in languages other than C++ for a variety of reasons. After a lot of research, my choices have pretty much narrowed down to Python and Java. I'm leaning towards Python because of its relationship to C, but with Java, from what I can see, I get a good introduction to using and creating test suites with Eclipse - there is also Processing which is pulling me towards Java. I'm not the kind of guy to tackle two languages at once, so which one would you recommend and why? What I want at the end is to have an additional language I can use for rapid development. Ease of learning isn't important to me as I'm willing to put in the time regardless. Ability to use the new language widely is.

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  • how to configure IP cam to stream using right network card?

    - by robin hood
    I have IP cam that supports RTSP streaming. It's connected to router with 2 network cards with IP1 and IP2 addresses. I make 2 connections to IP cam by IP1 and IP2 addresses from the same IP and I need to receive corresponding streams thru correct network card, but both streams (RTP over UDP) go thru IP1. How this can be resolved? I don't know if RTSP server binds UDP sockets to corresponding IP and I don't know what IP stack is in IP cam (weak end system or strong end system). I haven't found anything interesting in router configuration. As I understand, routing table cannot help me cos I'm connected from the same IP, is it right? Also Sorry for incomplete info but it's all I have at the moment. Thanks for your time.

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  • Directory name "cache" in IIS 5.

    - by Chuck Conway
    In IIS 5 one of the directories off the root has a leading underscore. All files under the directory are unreachable (404) from the browser. I have verified that the paths are correct. Other javascript files outside the directory comedown fine. Any thoughts? Example: http://fm74g4rndmu02.corp.com/_cache/softwarecommunity/api.js

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  • What advantage does Monad give us over an Applicative?

    - by arrowdodger
    I've read this article, but didn't understand last section. The author says that Monad gives us context sensitivity, but it's possible to achieve the same result using only an Applicative instance: let maybeAge = (\futureYear birthYear -> if futureYear < birthYear then yearDiff birthYear futureYear else yearDiff futureYear birthYear) <$> (readMay futureYearString) <*> (readMay birthYearString) It's uglier for sure, but beside that I don't see why we need Monad. Can anyone clear this up for me?

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  • Properly handling NSURLConnection errors

    - by Cal S
    Hi, I have a simple form interface set up that send username and password information to a server: (working) NSString *postData = [NSString stringWithFormat:@"user=%@&pass=%@",[self urlEncodeValue:sysUsername],[self urlEncodeValue:password]]; NSLog(@"Post data -> %@", postData); /// NSData* postVariables = [postData dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES]; NSMutableURLRequest* request = [[[NSMutableURLRequest alloc] init] autorelease]; NSString* postLength = [NSString stringWithFormat:@"%d", [postVariables length]]; NSURL* postUrl = [NSURL URLWithString:@"http://localhost/~csmith/cocoa/test.php"]; [request setURL:postUrl]; [request setHTTPMethod:@"POST"]; [request setValue:postLength forHTTPHeaderField:@"Content-Length"]; [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"]; [request setHTTPBody: postVariables]; NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:NULL error:NULL]; NSLog(@"Post data SENT & returned -> %@", returnData); How do I handle connection errors such as no internet connection, firewall, etc. Also, does this method use the system-wide proxy settings? Many of my users are behind a proxy. Thanks a lot!

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  • Client/Server communication via internet

    - by user957829
    Hi, Which is the best solution to communicate bidirectionally between a remote server and a client behind an internet box? UPnP with Sockets. HTTPS/Database Server and the client make 1 request every Xsec to know if there is new data. Client opens 1 connection on the server and it maintains open to make a tunnel. Thanks in advance for your help

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  • Avoiding dependency injection

    - by dotnetdev
    When coding, I often come across the following pattern: -A method calls another method (Fine), but the method being called/callee takes parameters, so in the wrapping method, I pass in parameters. Problem is, this dependency carrying can go on and on. How could I avoid this (any sample code appreciated)? Thanks

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  • CSS Brace Styles

    - by Nimbuz
    I'm unable to figure how the standard (or just popular) brace style names apply to CSS. Here're all the brace styles: /* one - pico? */ selector { property: value; property: value; } /* two */ selector { property: value; /* declaration starts on newline */ property: value; } /* three */ selector { property: value; property: value; } /* four - Allman or GNU?*/ selector { property: value; /* declaration starts on newline */ property: value; }? /* five */ selector { property: value; property: value; } /* six - horstmann? */ selector { property: value; /* declaration starts on newline */ property: value; } /* seven - banner?*/ selector { property: value; property: value; } /* eight */ selector { property: value; /* declaration starts on newline */ property: value; } Can someone please name each brace style for me? Many thanks!

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  • Sending emails?

    - by Kaep
    Hi i saw a post explaining how to send emails in python. But my problem is finding a server that will send my email on.. I read about setting one up and i read that it is a complicated process.. Can anyone help me find a server or give me a tip to set one up myself? Thanks!

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