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  • perl - universal operator overload

    - by Todd Freed
    I have an idea for perl, and I'm trying to figure out the best way to implement it. The idea is to have new versions of every operator which consider the undefined value as the identity of that operation. For example: $a = undef + 5; # undef treated as 0, so $a = 5 $a = undef . "foo"; # undef treated as '', so $a = foo $a = undef && 1; # undef treated as false, $a = true and so forth. ideally, this would be in the language as a pragma, or something. use operators::awesome; However, I would be satisfied if I could implement this special logic myself, and then invoke it where needed: use My::Operators; The problem is that if I say "use overload" inside My::Operators only affects objects blessed into My::Operators. So the question is: is there a way (with "use overoad" or otherwise) to do a "universal operator overload" - which would be called for all operations, not just operations on blessed scalars. If not - who thinks this would be a great idea !? It would save me a TON of this kind of code if($object && $object{value} && $object{value} == 15) replace with if($object{value} == 15) ## the special "is-equal-to" operator

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  • Robotlegs: Warning: Injector already has a rule for type

    - by MikeW
    I have a bunch of warning messages like this appear when using Robotlegs/Signals. Everytime this command class executes, which is every 2-3 seconds ..this message displays below If you have overwritten this mapping intentionally you can use "injector.unmap()" prior to your replacement mapping in order to avoid seeing this message. Warning: Injector already has a rule for type "mx.messaging.messages::IMessage", named "". The command functions fine otherwise but I think I'm doing something wrong anyhow. public class MessageReceivedCommand extends SignalCommand { [Inject] public var message:IMessage; ...etc.. do something with message.. } the application context doesnt map IMessage to this command, as I only see an option to mapSignalClass , besides the payload is received fine. Wonder if anyone knows how I might either fix or suppress this message. I've tried calling this as the warning suggests injector.unmap(IMessage, "") but I receive an error - no mapping found for ::IMessage named "". Thanks Edit: A bit more info about the error Here is the signal that I dispatch to the command public class GameMessageSignal extends Signal { public function GameMessageSignal() { super(IMessage); } } which is dispatched from a IPushDataService class gameMessage.dispatch(message.message); and the implementation is wired up in the app context via injector.mapClass(IPushDataService, PushDataService); along with the signal signalCommandMap.mapSignalClass(GameMessageSignal, MessageReceivedCommand); Edit #2: Probably good to point out also I inject an instance of GameMessageSignal into IPushDataService public class PushDataService extends BaseDataService implements IPushDataService { [Inject] public var gameMessage:GameMessageSignal; //then private function processMessage(message:MessageEvent):void { gameMessage.dispatch(message.message); } } Edit:3 The mappings i set up in the SignalContext: injector.mapSingleton(IPushDataService); injector.mapClass(IPushDataService, PushDataService);

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  • PHP loop hanging/interspersed/threaded through HTML

    - by sandyv
    I can't figure out how to say what I'm talking about which is a big part of why I'm stuck. In PHP I often see code like this html <?php language construct that uses brackets { some code; ?> more html <?php some more code; } ?> rest of html Is there any name for this? Having seen this lead me to try it out so here is a concrete example whose behavior doesn't make sense to me <div id="content"> <ul id="nav"> <?php $path = 'content'; $dir = dir($path); while(false !== ($file = $dir->read())) { if(preg_match('/.+\.txt/i', $file)) { echo "<li>$file</li>"; ?> </ul> <?php echo file_get_contents($path . '/' . $file); } } ?> </div> Which outputs roughly <div><ul><li></li></ul><li></li>...</div> instead of <div><ul><li></li>...</ul></div> which is what I thought would happen and what I want to happen.

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  • Using Visual Studio 2010 Express to create a surface I can draw to

    - by Joel
    I'm coming from a Java background and trying to port a simple version of Conway's Game of Life that I wrote to C# in order to learn the language. In Java, I drew my output by inheriting from JComponent and overriding paint(). My new canvas class then had an instance of the simulation's backend which it could read/manipulate. I was then able to get the WYSIWYG GUI editor (Matisse, from NetBeans) to allow me to visually place the canvas. In C#, I've gathered that I need to override OnPaint() to draw things, which (as far as I know) requires me to inherit from something (I chose Panel). I can't figure out how to get the Windows forms editor to let me place my custom class. I'm also uncertain about where in the generated code I need to place my class. How can I do this, and is putting all my drawing code into a subclass really how I should be going about this? The lack of easy answers on Google suggests I'm missing something important here. If anyone wants to suggest a method for doing this in WPF as well, I'm curious to hear it. Thanks

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  • Determining the chances of an event occurring when it hasn't occurred yet

    - by sanity
    A user visits my website at time t, and they may or may not click on a particular link I care about, if they do I record the fact that they clicked the link, and also the duration since t that they clicked it, call this d. I need an algorithm that allows me to create a class like this: class ClickProbabilityEstimate { public void reportImpression(long id); public void reportClick(long id); public double estimateClickProbability(long id); } Every impression gets a unique id, and this is used when reporting a click to indicate which impression the click belongs to. I need an algorithm that will return a probability, based on how much time has past since an impression was reported, that the impression will receive a click, based on how long previous clicks required. Clearly one would expect that this probability will decrease over time if there is still no click. If necessary, we can set an upper-bound, beyond which we consider the click probability to be 0 (eg. if its been an hour since the impression occurred, we can be pretty sure there won't be a click). The algorithm should be both space and time efficient, and hopefully make as few assumptions as possible, while being elegant. Ease of implementation would also be nice. Any ideas?

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  • Generating a python file

    - by fema
    Hi! I'm havin issues with python (imo python itself is an issue). I have a txt file, it contains a custom language and I have to translate it to a working python code. The input: import sys n = int(sys.argv[1]) ;;print "Beginning of the program!" LOOP i in range(1,n) {print "The number:";;print i} BRANCH n < 5 {print n ;;print "less than 5"} The wanted output looks exactly like this: import sys n = int(sys.argv[1]) print "Beginning of the program!" for i in range(1,n) : print "The number:" print i if n < 5 : print n print "less than 5" The name of the input file is read from parameter. The out file is out.py. In case of a wrong parameter, it gives an error message. The ;; means a new line. When I tried to do it, I made an array, I read all the lines into it, split by " ". Then I wanted to strip it from the marks I don't need. I made 2 loops, one for the lines, one for the words. So then I started to replace the things. Everything went fine until it came to the } mark. It finds it, but it can not replace or strip it. I have no more idea what to do. Could someone help me, please? Thanks in advance!

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  • Regarding Div Display

    - by user71723
    Hi to all, When i click on button,one div is showing..whenever i click on the body,that div will be hide. How can we achieve this functionality .. i write one code is as below. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <title>Untitled Document</title> <script language="javascript"> function HideSubMenus(e) { var targ; if (!e) var e = window.event; if (e.target) targ = e.target; else if (e.srcElement) targ = e.srcElement; if (targ.nodeType == 3) // defeat Safari bug targ = targ.parentNode; for (var i=0; i!=5; i++) { if (!targ) { break; } else if (targ.className=="divclass") { return; } targ = targ.parentNode; } if(document.getElementById("showdivid")) { document.getElementById("showdivid").style.display=''; } } </script> </head> <body onclick="HideSubMenus(event);"> <input type="button" name="button" value="Click ME" onclick="document.getElementById('showdivid').style.display='';" /> <div id="showdivid" class="divclass" style="display:none;"> TeSt DIV </div> </body> </html> regards raj

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  • Proper structure for dependency injection (using Guice)

    - by David B.
    I would like some suggestions and feedback on the best way to structure dependency injection for a system with the structure described below. I'm using Guice and thus would prefer solutions centered around it's annotation-based declarations, not XML-heavy Spring-style configuration. Consider a set of similar objects, Ball, Box, and Tube, each dependent on a Logger, supplied via the constructor. (This might not be important, but all four classes happen to be singletons --- of the application, not Gang-of-Four, variety.) A ToyChest class is responsible for creating and managing the three shape objects. ToyChest itself is not dependent on Logger, aside from creating the shape objects which are. The ToyChest class is instantiated as an application singleton in a Main class. I'm confused about the best way to construct the shapes in ToyChest. I either (1) need access to a Guice Injector instance already attached to a Module binding Logger to an implementation or (2) need to create a new Injector attached to the right Module. (1) is accomplished by adding an @Inject Injector injectorfield to ToyChest, but this feels weird because ToyChest doesn't actually have any direct dependencies --- only those of the children it instantiates. For (2), I'm not sure how to pass in the appropriate Module. Am I on the right track? Is there a better way to structure this? The answers to this question mention passing in a Provider instead of using the Injector directly, but I'm not sure how that is supposed to work. EDIT: Perhaps a more simple question is: when using Guice, where is the proper place to construct the shapes objects? ToyChest will do some configuration with them, but I suppose they could be constructed elsewhere. ToyChest (as the container managing them), and not Main, just seems to me like the appropriate place to construct them.

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  • Tableview not drilling down

    - by JoshD
    I have a Tableview which is loaded with a dummy list of exercises. I need to drill to a different page. My didSelectRow is being called, but not implementing the method. The app is a tab bar navigation app that loads a UITableView. #import <UIKit/UIKit.h> @interface Schedule : UIViewController <UITableViewDelegate, UITableViewDataSource> { NSArray *mySchedule; } @end #import "Schedule.h" #import "AnotherViewController.h" @implementation Schedule - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{ return mySchedule.count; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{ //create a cell UITableViewCell *cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"cell"]; //fill it with contents cell.textLabel.text = [mySchedule objectAtIndex:indexPath.row]; //return it return cell; } - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{ AnotherViewController *anotherViewController = [[AnotherViewController alloc] initWithNibName:@"AnotherViewController" bundle:nil]; [self.navigationController pushViewController:anotherViewController animated:YES]; [anotherViewController release]; } /* // The designated initializer. Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad. - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) { // Custom initialization } return self; } */ // Implement viewDidLoad to do additional setup after loading the view, typically from a nib. - (void)viewDidLoad { NSString *myFile = [[NSBundle mainBundle] pathForResource:@"exercise" ofType:@"plist"]; mySchedule = [[NSArray alloc] initWithContentsOfFile:myFile]; [super viewDidLoad]; }

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  • Matrix multiplication using pairs

    - by sc_ray
    Hi, I am looking into alternate ways to do a Matrix Multiplication. Instead of storing my matrix as a two-dimensional array, I am using a vector such as vector<pair<pair<int,int >,int > > to store my matrix. The pair within my pair (pair) stores my indices (i,j) and the other int stores the value for the given (i,j) pair. I thought I might have some luck implementing my sparse array this way. The problem is when I try to multiply this matrix with itself. If this was a 2-d array implementation, I would have multiplied the matrix as follows: for(i=0; i<row1; i++) { for(j=0; j<col1; j++) { C[i][j] = 0; for(k=0; k<col2; k++) C[i][j] += A[i][j] * A[j][k]; } } Can somebody point out a way to achieve the same result using my vector of 'pair of pairs'? Thanks

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  • Immutability and shared references - how to reconcile?

    - by davetron5000
    Consider this simplified application domain: Criminal Investigative database Person is anyone involved in an investigation Report is a bit of info that is part of an investigation A Report references a primary Person (the subject of an investigation) A Report has accomplices who are secondarily related (and could certainly be primary in other investigations or reports These classes have ids that are used to store them in a database, since their info can change over time (e.g. we might find new aliases for a person, or add persons of interest to a report) If these are stored in some sort of database and I wish to use immutable objects, there seems to be an issue regarding state and referencing. Supposing that I change some meta-data about a Person. Since my Person objects immutable, I might have some code like: class Person( val id:UUID, val aliases:List[String], val reports:List[Report]) { def addAlias(name:String) = new Person(id,name :: aliases,reports) } So that my Person with a new alias becomes a new object, also immutable. If a Report refers to that person, but the alias was changed elsewhere in the system, my Report now refers to the "old" person, i.e. the person without the new alias. Similarly, I might have: class Report(val id:UUID, val content:String) { /** Adding more info to our report */ def updateContent(newContent:String) = new Report(id,newContent) } Since these objects don't know who refers to them, it's not clear to me how to let all the "referrers" know that there is a new object available representing the most recent state. This could be done by having all objects "refresh" from a central data store and all operations that create new, updated, objects store to the central data store, but this feels like a cheesy reimplementation of the underlying language's referencing. i.e. it would be more clear to just make these "secondary storable objects" mutable. So, if I add an alias to a Person, all referrers see the new value without doing anything. How is this dealt with when we want to avoid mutability, or is this a case where immutability is not helpful?

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  • Which Perl moudle can handle variety of date formats with unicode characters ?

    - by ram
    My requirement is parsing xml files which contains wide varieties of timestamps based on the locales at which they are written. They may contain Unicode characters in case of Chinese or Korean locales. I have to parse these timestamps and put then in a standard format something like 2009-11-26 12:40:54 to put them in a oracle database. Sometimes I may not even know the locale and yet I have to parse the timestamps. I am looking for a module that automatically detects the timestamp format (including unicode characters for am and pm in their local language) and converts in to epoch time so that I can convert it back to what ever way I like to. I have gone through similar questions in this forum. Few suggested DateFormat module, and Date::Parse module. The perl distribution I am using is 5.10 so Date::Manip doesn't come as a core module. As I am supposed to use just the basic core modules and few CPAN modules(on request I cannot ask for all), I request you to kindly suggest me a good module that suffices all my requirements. Thanks in advance

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  • Computing, storing, and retrieving values to and from an N-Dimensional matrix

    - by Adam S
    This question is probably quite different from what you are used to reading here - I hope it can provide a fun challenge. Essentially I have an algorithm that uses 5(or more) variables to compute a single value, called outcome. Now I have to implement this algorithm on an embedded device which has no memory limitations, but has very harsh processing constraints. Because of this, I would like to run a calculation engine which computes outcome for, say, 20 different values of each variable and stores this information in a file. You may think of this as a 5(or more)-dimensional matrix or 5(or more)-dimensional array, each dimension being 20 entries long. In any modern language, filling this array is as simple as having 5(or more) nested for loops. The tricky part is that I need to dump these values into a file that can then be placed onto the embedded device so that the device can use it as a lookup table. The questions now, are: What format(s) might be acceptable for storing the data? What programs (MATLAB, C#, etc) might be best suited to compute the data? C# must be used to import the data on the device - is this possible given your answer to #1?

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  • java array pass by reference does not work?

    - by stdnoit
    guys i thought almost all language including java pass array into function as reference (modifiable) but somehow it does not work here. and the testArray is still 1,2,3 with size of 3 strange enough, when if i change result[i] = 2 to a[1] =2; it work . it did pass by reference what is wrong with this code? at the end, i had a = result; (which update the a). did result get removed from stack. that is why a still get to the original a ? i am confused. thanks class Test { public static void main(String[] args) { int[] testArray = {1,2,3}; equalize(testArray, 6); System.out.println("test Array size :" + testArray.length); for(int i = 0; i < testArray.length; i++) System.out.println(testArray[i]); } public static void equalize(int[] a, int biggerSize) { if(a.length > biggerSize) throw new Error("Array size bigger than biggerSize"); int[] result = new int[biggerSize]; // System.arraycopy(a, 0, result, 0, a.length); // int array default value should be 0 for(int i = 0; i < biggerSize; i++) result[i] = 2; a = result; } }

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  • A generic C++ library that provides QtConcurrent functionality?

    - by Lucas
    QtConcurrent is awesome. I'll let the Qt docs speak for themselves: QtConcurrent includes functional programming style APIs for parallel list processing, including a MapReduce and FilterReduce implementation for shared-memory (non-distributed) systems, and classes for managing asynchronous computations in GUI applications. For instance, you give QtConcurrent::map() an iterable sequence and a function that accepts items of the type stored in the sequence, and that function is applied to all the items in the collection. This is done in a multi-threaded manner, with a thread pool equal to the number of logical CPU's on the system. There are plenty of other function in QtConcurrent, like filter(), filteredReduced() etc. The standard CompSci map/reduce functions and the like. I'm totally in love with this, but I'm starting work on an OSS project that will not be using the Qt framework. It's a library, and I don't want to force others to depend on such a large framework like Qt. I'm trying to keep external dependencies to a minimum (it's the decent thing to do). I'm looking for a generic C++ framework that provides me with the same/similar high-level primitives that QtConcurrent does. AFAIK boost has nothing like this (I may be wrong though). boost::thread is very low-level compared to what I'm looking for. I know C# has something very similar with their Parallel Extensions so I know this isn't a Qt-only idea. What do you suggest I use?

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  • Silverlight: Button template with texttrimming cut off

    - by dex3703
    I'm replacing the default Button template's ContentPresenter with a TextBlock, so the text can be trimmed when it's too long. Works fine in WPF. In Silverlight the text gets pushed to one edge and cut off on the left, even when there's space on the right: Template is nothing special, just replaced the ContentPresenter with the TextBlock: <Border x:Name="bdrBackground" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" /> <Rectangle x:Name="rectMouseOverVisualElement" Opacity="0"> <Rectangle.Fill> <SolidColorBrush x:Name="rectMouseOverColor" Color="{StaticResource MouseOverItemBgColor}"/> </Rectangle.Fill> </Rectangle> <Rectangle x:Name="rectPressedVisualElement" Opacity="0" Style="{TemplateBinding Tag}"/> <TextBlock x:Name="textblock" Text="{TemplateBinding Content}" TextTrimming="WordEllipsis" TextWrapping="NoWrap" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Margin="{TemplateBinding Padding}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/> <Rectangle x:Name="rectDisabledVisualElement" Opacity="0" Style="{StaticResource RectangleDisabledStyle}"/> <Rectangle x:Name="rectFocusVisualElement" Opacity="0" Style="{StaticResource RectangleFocusStyle}"/> </Grid> </ControlTemplate> How do I fix this? More info: With the latest comment about HorizontalAlignment, it's clear that SL's implementation of TextTrimming differs from WPF's. In SL, TextTrimming only really works if the text is aligned left. SL isn't smart enough to align the text the way WPF does. For instance: WPF button: SL button with the textblock horizontalalignment = left: SL button with textblock horizontalalignment = center:

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  • Where to place interactive objects in JavaScript?

    - by Chris
    I'm creating a web based application (i.e. JavaScript with jQuery and lots of SVG) where the user interacts with "objects" on the screen (think of DIVs that can be draged around, resized and connected by arraows - like a vector drawing programm or a graphical programming language). As each "object" contains individual information but is allways belonging to a "class" of elements it's obvious that this application should be programmed by using an OOP approach. But where do I store the "objects" best? Should I create a global structure ("registry") with all (JS native) objects and tell them "draw yourself on the DOM"? Or should I avoid such a structure and think of the (relevant) DOM nodes as my objects and attach the relevant data as .data() to them? The first approach is very MVC - but I guess the attachment of all the event handlers will be non trivial. The second approach will handle the events in a trivial way and it doesn't create a duplicate structure, but I guess the usual OO stuff (like methods) will be more complex. What do you recomend? I think the answer will be JavaScript and SVG specific as "usual" programming languages don't have such a highly organized output "canvas".

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  • Dynamic Select boxes page load

    - by Chris
    Hello, I have a dynamic chained select box that I am attempting to show the value of on a page load. In my chained select box, it will default to the first option within the select box on page load, could anyone provide assitance? I stumbled upon this thread, but I can't seem to translate what they are doing with that answer to my language of CF. Dynamic chained drop downs on page refresh Here is the JS script I am using. function dynamicSelect(id1, id2) { // Feature test to see if there is enough W3C DOM support if (document.getElementById && document.getElementsByTagName) { // Obtain references to both select boxes var sel1 = document.getElementById(id1); var sel2 = document.getElementById(id2); // Clone the dynamic select box var clone = sel2.cloneNode(true); // Obtain references to all cloned options var clonedOptions = clone.getElementsByTagName("option"); // Onload init: call a generic function to display the related options in the dynamic select box refreshDynamicSelectOptions(sel1, sel2, clonedOptions); // Onchange of the main select box: call a generic function to display the related options in the dynamic select box sel1.onchange = function() { refreshDynamicSelectOptions(sel1, sel2, clonedOptions); } } } function refreshDynamicSelectOptions(sel1, sel2, clonedOptions) { // Delete all options of the dynamic select box while (sel2.options.length) { sel2.remove(0); } // Create regular expression objects for "select" and the value of the selected option of the main select box as class names var pattern1 = /( |^)(select)( |$)/; var pattern2 = new RegExp("( |^)(" + sel1.options[sel1.selectedIndex].value + ")( |$)"); // Iterate through all cloned options for (var i = 0; i < clonedOptions.length; i++) { // If the classname of a cloned option either equals "select" or equals the value of the selected option of the main select box if (clonedOptions[i].className.match(pattern1) || clonedOptions[i].className.match(pattern2)) { // Clone the option from the hidden option pool and append it to the dynamic select box sel2.appendChild(clonedOptions[i].cloneNode(true)); } } } Thanks so much for any assistance

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  • Objective C: Function returning correct data for the first time of call and null for other times

    - by Kooshal Bhungy
    Hi all, Am a beginner in objective C, i am implementing a function that would query a web server and display the returning string in console. I am calling the function (getDatafromServer) repeatedly in a loop. The problem is that the first time am getting the value whereas the other times, it returns me a (null) in console... I've searched about memory management and check out on the forums but none have worked. Can you please guys tell me where am wrong in the codes below? Thanks in advance.... @implementation RequestThread +(void)startthread:(id)param{ while (true) { //NSLog(@"Test threads"); sleep(5); NSLog(@"%@",[self getDatafromServer]); } } +(NSString *) getDatafromServer{ NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; NSString *myRequestString = @"name=Hello%20&[email protected]"; NSData *myRequestData = [NSData dataWithBytes:[myRequestString UTF8String] length:[myRequestString length]]; NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL: [NSURL URLWithString:@"http://192.168.1.32/gs/includes/widget/getcalls.php?user=asdasd&passw=asdasdasd"]]; [request setHTTPMethod:@"POST"]; [request setHTTPBody: myRequestData]; [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"content-type"]; NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil]; NSString *myString = [NSString stringWithUTF8String:[returnData bytes]]; [myRequestString release]; [request release]; [returnData release]; return myString; [pool release]; } @end

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  • Best (Java) book for understanding 'under the bonnet' for programming?

    - by Ben
    What would you say is the best book to buy to understand exactly how programming works under the hood in order to increase performance? I've coded in assembly at university, I studied computer architecture and I obviously did high level programming, but what I really dont understand is things like: -what is happening when I perform a cast -whats the difference in performance if I declare something global as opposed to local? -How does the memory layout for an ArrayList compare with a Vector or LinkedList? -Whats the overhead with pointers? -Are locks more efficient than using synchronized? -Would creating my own array using int[] be faster than using ArrayList -Advantages/disadvantages of declaring a variable volatile I have got a copy of Java Performance Tuning but it doesnt go down very low and it contains rather obvious things like suggesting a hashmap instead of using an ArrayList as you can map the keys to memory addresses etc. I want something a bit more Computer Sciencey, linking the programming language to what happens with the assembler/hardware. The reason im asking is that I have an interview coming up for a job in High Frequency Trading and everything has to be as efficient as possible, yet I cant remember every single possible efficiency saving so i'd just like to learn the fundamentals. Thanks in advance

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  • Datastructure choices for highspeed and memory efficient detection of duplicate of strings

    - by Jonathan Holland
    I have a interesting problem that could be solved in a number of ways: I have a function that takes in a string. If this function has never seen this string before, it needs to perform some processing. If the function has seen the string before, it needs to skip processing. After a specified amount of time, the function should accept duplicate strings. This function may be called thousands of time per second, and the string data may be very large. This is a highly abstracted explanation of the real application, just trying to get down to the core concept for the purpose of the question. The function will need to store state in order to detect duplicates. It also will need to store an associated timestamp in order to expire duplicates. It does NOT need to store the strings, a unique hash of the string would be fine, providing there is no false positives due to collisions (Use a perfect hash?), and the hash function was performant enough. The naive implementation would be simply (in C#): Dictionary<String,DateTime> though in the interest of lowering memory footprint and potentially increasing performance I'm evaluating a custom data structures to handle this instead of a basic hashtable. So, given these constraints, what would you use? EDIT, some additional information that might change proposed implementations: 99% of the strings will not be duplicates. Almost all of the duplicates will arrive back to back, or nearly sequentially. In the real world, the function will be called from multiple worker threads, so state management will need to be synchronized.

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  • Attempt to create nested for loops generating missing arguments error

    - by JerryK
    Am attempting to teach myself to program using Tcl. (I want to become more familiar with the language to understand someone else's code - SCID chess) The task i've set myself to motivate my learing of Tcl is to solve the 8 queens problem. My approach to creating a program is to sucessively 'prototype' a solution. So. I'm up to nesting a for loop holding the q pos on row 2 inside the for loop holding the q pos on row 1 Here is my code set allowd 1 set notallowd 0 for {set r1p 1} {$r1p <= 8} {incr r1p } { puts "1st row q placed at $r1p" ;# re-initialize r2 'free for q placemnt' array after every change of r1 q pos: for {set i 1 } {$i <= 8} {incr i} { set r2($i) $allowd } for { set r2($r1p) $notallowd ; set r2([eval $r1p-1]) $notallowd ; set r2([eval $r1p+1]) $notallowd ; set r2p 1} {$r2p <= 8} { incr r2p ;# end of 'next' arg of r2 forloop } ;# commnd arg of r2 forloop placed below: {puts "2nd row q placed at $r2p" } } My problem is that when i run the code the interpreter is aborting with the fatal error: "wrong #args should be for start test next command. I've gone over my code a few times and can't see that i've missed any of the for loop arguments.

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  • How to have table span the entire height?

    - by Yogendra
    Hi All, I have a html table and I am trying to have it span the entire page height. For some reason I am not able to get this to work. I have set the html, body and table height to be 100%, but the table still does not occupy the entire 100%. Heres the code. It is very basic because I am just trying to have the table occupy the entire height. <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplication1.WebForm1" %> <style type="text/css"> body,html { margin:0; padding:0; height:100%; } </style> <table border="2" cellpadding="0" cellspacing="0" style="height:100%; width:100%" > <tr> <td>ABCD</td> </tr> </table> </form> I tried for couple of hours and I could not get it to work. Any help is really appreciated.

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  • problems getting HTTPRiot working

    - by bwizzy
    I've got an iphone app where I'm trying to use HTTPRiot to make some API calls to a web app. Problem is I can't see that none of the HTTPRiot delegate methods are being called. I've got a log in all the delegate methods, and I'm also looking at the webserver log. I see that the URL is being hit. //API.h #import <Foundation/Foundation.h> #include <HTTPRiot/HTTPRiot.h> @interface API : HRRestModel { } +(void)runTest; @end //API.m #import "API.h" @implementation API + (void)initialize { NSLog(@"api initialize"); [self setDelegate:self]; [self setBaseURL:[NSURL URLWithString:@"http://localhost:3000/api"]]; [self setBasicAuthWithUsername:@"demo" password:@"123456"]; NSDictionary *params = [NSDictionary dictionaryWithObject:@"1234567" forKey:@"api_key"]; [self setDefaultParams:params]; }//end initialize +(void)runTest { NSLog(@"api run test"); // Would send a request to http://localhost:1234/api/people/1?api_key=1234567 [self getPath:@"/save_diet" withOptions:nil object:nil]; } +(void)restConnection:(NSURLConnection *)connection didReturnResource:(id)resource object:(id)object { NSLog(@"didReturnResource"); } +(void)restConnection:(NSURLConnection *)connection didReceiveResponse:(NSHTTPURLResponse *)response object:(id)object { NSLog(@"didReceiveResponse"); } +(void)restConnection:(NSURLConnection *)connection didReceiveParseError:(NSError *)error responseBody:(NSString *)body object:(id)object { NSLog(@"didReceiveParseError"); } +(void)restConnection:(NSURLConnection *)connection didReceiveError:(NSError *)error response:(NSHTTPURLResponse *)response object:(id)object { NSLog(@"didReceiveError"); } +(void)restConnection:(NSURLConnection *)connection didFailWithError:(NSError *)error object:(id)object { NSLog(@"didFailWithError"); } @end //test code [API runTest]; //log output

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  • Scroll table upwards or downwards using up and down button

    - by Psinyee
    I want to create a banner scrolling function for my homepage. I am not too sure of which programming language to use here. I want to code something similar to: http://www.squidfaceandthemeddler.com/. But I want the footer to remain at the same position while the user scroll the table. Is it possible to get that result? I have create a simple tables and 2 images for the user to click on here is my code for the tables: <div id="banner" style="height:750px; width:600px; overflow:scroll;" > <table width="750px" height="600px"> <tr> <td><a href="sale_1.php"><img src="banner1.png"/></a></td> </tr> </table> <table width="750px" height="600px"> <tr> <td><a href="sale_2.php"><img src="banner2.png"/></a></td> </tr> </table> <table width="750px" height="600px"> <tr> <td><a href="sale_3.php"><img src="banner3.png"/></a></td> </tr> </table> </div> and this is the upwards and downwards button for the scrolling: <table width="750px" height="30px"> <tr> <td align="right"><img src="images/up_arrow.png"/><img src="images/down_arrow.png"/></td> </tr> </table>

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