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  • How to efficiently implement a strategy pattern with spring ?

    - by Anth0
    I have a web application developped in J2EE 1.5 with Spring framework. Application contains "dashboards" which are simple pages where a bunch of information are regrouped and where user can modify some status. Managers want me to add a logging system in database for three of theses dashboards. Each dashboard has different information but the log should be traced by date and user's login. What I'd like to do is to implement the Strategy pattern kind of like this : interface DashboardLog { void createLog(String login, Date now); } // Implementation for one dashboard class PrintDashboardLog implements DashboardLog { Integer docId; String status; void createLog(String login, Date now){ // Some code } } class DashboardsManager { DashboardLog logger; String login; Date now; void createLog(){ logger.log(login,now); } } class UpdateDocAction{ DashboardsManager dbManager; void updateSomeField(){ // Some action // Now it's time to log dbManagers.setLogger = new PrintDashboardLog(docId, status); dbManagers.createLog(); } } Is it "correct" (good practice, performance, ...) to do it this way ? Is there a better way ? Note :I did not write basic stuff like constructors and getter/setter.

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  • CSS "Cover" - No scroll bars?

    - by Lynda
    I am using the cover property to create a background image that fills the background and resizes with the browser. But I run into one issue, the page has a lot of content and no scroll bars appear for me to scroll down! Here is the code I am using: body{ background: url(path.jpg) no-repeat center center fixed; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; /* Cover for IE 7/8 */ filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(src='path.jpg', sizingMethod='scale'); -ms-filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(src='path.jpg', sizingMethod='scale'); /* End Cover for IE 7/8 */ background-size: cover; background-color: transparent !important; position:fixed; top: 0; left: 0; width: 100%; height:100%; max-width:2500px; max-height:1500px; z-index:1; } If I remove position:fixed; I get the scroll bars back but the background image disappears. What is the best way to tackle this and have both scroll bars and the background cover image? Note: I am using jQuery and would use a JS answer if it works (though I prefer a CSS only answer.)

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  • Self organizing layouts

    - by user613326
    Quite a while ago i was more in websites building then i am now. In my time there where huge debates about what to use; tables or pure CSS alternatives. I went out of the webdesigning, but now an old question re-surfaces. What i would like to create is a web page design that depending on screensize, would self organize the page into columns, so that for example on a PDA it would show 1 column On an old computer monitor, it would show 2 colomns, and on a widescreen laptop it would show 3 columns. I forgot how this was called and how it was done in the past, it had to do with XML and storing data seperate from design (if i remember well), perhaps these days better methods exist to do that, does this, anyone ring this a bell ? Also i note a lot is possible with Jquery and and brouwser depending webkits. But i need to make sure that it would run on all (modern) brouwsers : Iexplorer, Firefox, chrome And Jquery is nice too, but i am kinda woried that some day one of these brouwser vendors decides that jscript like java isnt enabled by default (or is that very unlikely ?)11 Perhaps someone can point me to a method that is the prefered way to do this.

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  • Execute a block of database querys

    - by Nightmare
    I have the following task to complete: In my program a have a block of database querys or questions. I want to execute these questions and wait for the result of all questions or catch an error if one question fails! My Question object looks like this (simplified): public class DbQuestion(String sql) { [...] } [...] //The answer is just a holder for custom data... public void SetAnswer(DbAnswer answer) { //Store the answer in the question and fire a event to the listeners this.OnAnswered(EventArgs.Empty); } [...] public void SetError() { //Signal an Error in this query! this.OnError(EventArgs.Empty); } So every question fired to the database has a listener that waits for the parsed result. Now I want to fire some questions asynchronous to the database (max. 5 or so) and fire an event with the data from all questions or an error if only one question throws one! Which is the best or a good way to accomplish this task? Can I really execute more then one question parallel and stop all my work when one question throws an error? I think I need some inspiration on this... Just a note: I´m working with .NET framework 2.0

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  • Calling NSFetchedResultsController & CoreData experts

    - by JK
    I am having a few nagging issues with NSFetchedResultsController and CoreData, any of which I would be very grateful to get help on. Issue 1 - Updates: I update my store on a background thread which results in certain rows being delete, inserted or updated. The changes are merged into the context on the main thread using the "mergeChangesFromContextDidSaveNotification:" method. Inserts and deletes are updated properly, but updates are not (e.g. the cell label is not updated with the change) although I have confirmed the updates to come through the contextDidSaveNotifcation, exactly like the inserts and deleted. My current workaround is to temporarily change the staleness interval of the context to 0, but this does not seem like the ideal solution. Issue 2 - Deleting objects: My fetch batch size is 20. If an object is deleted by the background thread which is in the first 20 rows, everything works fine. But if the object is after the first 20 rows and the table is scrolled down, a "CoreData could not fulfill a fault" error is raised. I have tried resaving the context and reperforming the frc fetch - all to no avail. Note: In this scenario, the frc delegate method "didChangeObject...." is not called for the delete - I assume this is because the object in question had not been faulted at that time (as it is was outside the initial fetch range). But for some reason, the context still thinks the object is around, although is has been deleted from the store. Issue 3 - Deleting sections : When the deletion of a row leads to the deletion of a section, I have gotten the "invalid number of rows in section???" error. I have worked around this by removing the "reloadSection" line from the NSFetchedResultsChangeMove: section and replacing it with "[tableView insertRowsAtIndexPaths...." This seems to work, but once again, I am not sure if this is the best solution. Any help would be greatly appreciated. Thank you!

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  • How to use linux csplit to chop up massive XML file?

    - by Fred
    Hi everyone, I have a gigantic (4GB) XML file that I am currently breaking into chunks with linux "split" function (every 25,000 lines - not by bytes). This usually works great (I end up with about 50 files), except some of the data descriptions have line breaks, and so frequently the chunk files do not have the proper closing tags - and my parser chokes halfway through processing. Example file: (note: normally each "listing" xml node is supposed to be on its own line) <?xml version="1.0" encoding="UTF-8"?> <listings> <listing><date>2009-09-22</date><desc>This is a description WITHOUT line breaks and works fine with split</desc><more_tags>stuff</more_tags></listing> <listing><date>2009-09-22</date><desc>This is a really annoying description field WITH line breaks that screw the split function</desc><more_tags>stuff</more_tags></listing> </listings> Then sometimes my split ends up like <?xml version="1.0" encoding="UTF-8"?> <listings> <listing><date>2009-09-22</date><desc>This is a description WITHOUT line breaks and works fine with split</desc><more_tags>stuff</more_tags></listing> <listing><date>2009-09-22</date><desc>This is a really annoying description field WITH line breaks ... EOF So - I have been reading about "csplit" and it sounds like it might work to solve this issue. I cant seem to get the regular expression right... Basically I want the same output of ~50ish files Something like: *csplit -k myfile.xml '/</listing>/' 25000 {50} Any help would be great Thanks!

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  • Suggestions on error handling of Win32 C++ code: AtlThrow vs. STL exceptions

    - by EmbeddedProg
    In writing Win32 C++ code, I'd appreciate some hints on how to handle errors of Win32 APIs. In particular, in case of a failure of a Win32 function call (e.g. MapViewOfFile), is it better to: use AtlThrowLastWin32 define a Win32Exception class derived from std::exception, with an added HRESULT data member to store the HRESULT corresponding to value returned by GetLastError? In this latter case, I could use the what() method to return a detailed error string (e.g. "MapViewOfFile call failed in MyClass::DoSomething() method."). What are the pros and cons of 1 vs. 2? Is there any other better option that I am missing? As a side note, if I'd like to localize the component I'm developing, how could I localize the exception what() string? I was thinking of building a table mapping the original English string returned by what() into a Unicode localized error string. Could anyone suggest a better approach? Thanks much for your insights and suggestions.

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  • Google Analytics, Install Tracking android

    - by vvieux
    Hi, I want track install referer for my application using google analytics. I don't want use the Tracking Pageviews and Events feature, only install. So I added the sdk jar in my app, add these lines to the manifest : <receiver android:name="com.google.android.apps.analytics.AnalyticsReceiver" android:exported="true"> <intent-filter> <action android:name="com.android.vending.INSTALL_REFERRER" /> </intent-filter> </receiver> And publish the app. But how can see the stats ? I never entered my UA-xxxxxxx id. For the Pageviews and Events tracking it's here : tracker.start("UA-YOUR-ACCOUNT-HERE", this); But as thew readme says : (NOTE: do not start the GoogleAnalyticsTracker in your Application onCreate() method if using referral tracking). But with referer where do I put my id ? And what is the url to watch in the google analytics console ? Thx

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  • ASP.NET 2.0 in Virtual Trying to Use SQL State Server

    - by user251660
    We have IIS 6 running on a W2003 Server. The root web site is running a v1.1 site. Under this site we have a virtual running a v2.0 site (with a separate application pool). The web.config for the root site is using SQL as its state server and has a 1.1 SQL state server database installed. The 2.0 virtual web.config does not need state and its web.config has no reference to a state server. When we attempt to call the virtual we receive this error message. "Unable to use SQL Server because ASP.NET version 2.0 Session State is not installed on the SQL server. Please install ASP.NET Session State SQL Server version 2.0 or above. This issue is currently only occurring on one web server. The rest are able to run the 2.0 virtual application. I also notice that if we call the 2.0 virtual with the IP address it does not generate the error, however if we call it with the host header name it generates the error (this behavior is only on the 1 web server with the error, all the others can be called with either the ip or host header without error). As an additional note the root and virtual are running with SSL. My theory is that the virtual 2.0 application is inheriting the 1.1 web.config state server entry from the root and when it looks at the state server it sees it as a 1.1 version and reports the error that it needs a 2.0 state server. I however cannot understand why the other servers are not behaving in this matter. All of the servers are on the same OS service pack as well as the same version of .net framework. Any ideas? Thanks

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  • WHY JSLint complains: "someFunction() was used before it was defined"?

    - by 7hi4g0
    Searching for the JSLint error "was used before it was defined" i've found these: JSLint: Using a function before it's defined error Function was used before it was defined - JSLint JSLint: was used before it was defined jsLint error: “somefunction() was used before it was defined” jslint - Should we tolerate misordered definitions? Problem None of those answers WHY the error is shown. Elaboration According to the ECMA-262 Specification functions are evaluated before execution starts, hence all functions declared using the function keyword are available to all the code idenpendent of the place they were declared (assuming they are acessible on that scope). This is otherwise known as hoisting. Douglas Crockford seems to think it is better to declare every function before the code that uses it regardless of the hoisting effect. According to StackOverflowNewbie in his question, this raises some code organization problems. Not to mention some people, like me, prefer to declare their functions underneath the main/init code. On those questions there are some ways to avoid or fix the error, such as using function expressions vs function declarations. But none of them showed me the reason of the error. Not even Crockford's site. Question(s) Why is it an error to call a function before the declaration, even if it was declared using the function keyword? Is it better to use function expressions instead of function declaration in the JSLint context? If one is preferred, why? Note Not looking for answers like: Crockford is a tyrant Is just Crockford's opinion Thank you :*

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  • UIAlertView Will not show

    - by John
    I have a program that is requesting a JSON string. I have created a class that contains the connect method below. When the root view is coming up, it does a request to this class and method to load up some data for the root view. When I test the error code (by changing the URL host to 127.0.0.1), I expect the Alert to show. Behavior is that the root view just goes black, and the app aborts with no alert. No errors in debug mode on the console, either. Any thoughts as to this behavior? I've been looking around for hints to this for hours to no avail. Thanks in advance for your help. Note: the conditional for (error) is called, as well as the UIAlertView code. - (NSString *)connect:(NSString *)urlString { NSString *jsonString; UIApplication *app = [UIApplication sharedApplication]; app.networkActivityIndicatorVisible = YES; NSError *error = nil; NSURLResponse *response = nil; NSURL *url = [[NSURL alloc] initWithString:urlString]; NSURLRequest *req = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:10]; NSData *_response = [NSURLConnection sendSynchronousRequest: req returningResponse: &response error: &error]; if (error) { /* inform the user that the connection failed */ //AlertWithMessage(@"Connection Failed!", message); UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Oopsie!" message:@"Unable to connect! Try later, thanks." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles: nil]; [alert show]; [alert release]; } else { jsonString = [[[NSString alloc] initWithData:_response encoding:NSUTF8StringEncoding] autorelease]; } app.networkActivityIndicatorVisible = NO; [url release]; return jsonString; }

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  • Difference in calling redefined functions in F# and Clojure

    - by Michiel Borkent
    In F#: > let f x = x + 2;; val f : int -> int > let g x = f x;; val g : int -> int > g 10;; val it : int = 12 > let f x = x + 3;; val f : int -> int > g 10;; val it : int = 12 In Clojure: (defn f [x] (+ x 2)) (defn g [x] (f x)) (g 10) ;; => 12 (defn f [x] (+ x 3)) (g 10) ;; => 13 Note that in Clojure the most recent version of f gets called in the last line. In F# however still the old version of f is called. Why is this?

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  • typedef a functions prototype

    - by bitmask
    I have a series of functions with the same prototype, say int func1(int a, int b) { // ... } int func2(int a, int b) { // ... } // ... Now, I want to simplify their definition and declaration. Of course I could use a macro like that: #define SP_FUNC(name) int name(int a, int b) But I'd like to keep it in C, so I tried to use the storage specifier typedef for this: typedef int SpFunc(int a, int b); This seems to work fine for the declaration: SpFunc func1; // compiles but not for the definition: SpFunc func1 { // ... } which gives me the following error: error: expected '=', ',', ';', 'asm' or '__attribute__' before '{' token Is there a way to do this correctly or is it impossible? To my understanding of C this should work, but it doesn't. Why? Note, gcc understands what I am trying to do, because, if I write SpFunc func1 = { /* ... */ } it tells me error: function 'func1' is initialized like a variable Which means that gcc understands that SpFunc is a function type.

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  • Comparison of Java and .NET technologies/frameworks

    - by Paul Sasik
    I work in a shop that is a mix of mostly Java and .NET technologists. When discussing new solutions and architectures we often encounter impedance in trying to compare the various technologies, frameworks, APIs etc. in use between the two camps. It seems that each camp knows little about the other and we end up comparing apples to oranges and forgetting about the bushels. While researching the topic I found this: Java -- .Net rough equivalents It's a nice list but it's not quite exhaustive and is missing the key .NET 3.0 technologies and a few other tidbits. To complete that list: what are the near/rough equivalents (or a combination of technologies) in Java to the following in .NET? WCF WPF Silverlight = JavaFx WF = jBMP (Java Business Process Management) Generics Lambda expressions = lambdaJ project or Closures Linq (not Linq-to-SQL) ...have i missed anything else? Note that I omitted technologies that are already covered in the linked article. I would also like to hear feedback on whether the linked article is accurate. Thanks. (Will CW if requested.)

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  • What should I do from here?

    - by Sunscreen
    Hi all, First of all, the site rocks. You can ask and get specific answers, mainly, for programming issues. This question is more generic. I studied Physics for my bachelors and Digital Image Processing for my masters, ended on September 2001. From then on I started working as a developer and software analyst. I worked, and working, witn C, C++, AIX OS, XP OS, MFC 4.21. I also did some data translations from EDIFACT to XML and viceversa. I trained users for the applications that I was running, I created documents (detailed design docs mainly), though most of the time I wrote, and I still write, code. Recently I applied for the best greek, graduate university for my MBA and they accepted me, starting on Jan 2011. I am a developer with no specific insight with the languages I work. I can be very productive with some subsets of the languages that the companies I worked for use, though this is a limited thing for a developer. If I get my MBA I can be a semi-businees analyst ot consultant, as I am now a semi-developer. The problem is that I can do some but not all in a designated working area. What should I do from here? Should I get my MBA and look forswitching industries? Should I read and excersise myself with new languages and frameworks? Should I be more focussed to the deligations from my current job (currently I work with MFC)? Just for the note, I am 32 and I feel I am wasting my time. I am not getting the best that I can get from is current position (and I work here for 3+ years). Thanks all, Sun

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  • Improve a regex statement in order to be as efficient as it can be

    - by user551625
    I have a PHP program that, at some point, needs to analyze a big amount of HTML+javascript text to parse info. All I want to parse needs to be in two parts. Seperate all "HTML goups" to parse Parse each HTML group to get the needed information. In the 1st parse it needs to find: <div id="myHome" And start capturing after that tag. Then stop capturing before <span id="nReaders" And capture the number that comes after this tag and stop. In the 2nd parse use the capture nº 1 (0 has the whole thing and 2 has the number) from the parse made before and then find . I already have code to do that and it works. Is there a way to improve this, make it easier for the machine to parse? preg_match_all('%<div id="myHome"[^>]>(.*?)<span id="nReaders[^>]>([0-9]+)<"%msi', $data, $results, PREG_SET_ORDER); foreach($results AS $result){ preg_match_all('%<div class="myplacement".*?[.]php[?]((?:next|before))=([0-9]+).*?<tbody.*?<td[^>]>.*?[0-9]+"%msi', $result[1], $mydata, PREG_SET_ORDER); //takes care of the data and finish the program Note: I need this for a freeware program so it must be as general as possible and, if possible, not use php extensions ADD: I ommitted some parts here because I didn't expect for answers like those. There is also a need to parse text inside one of the tags that is in the document. It may be the 6th 7th or 8th tag but I know it is after a certain tag. The parser I've checked (thx profitphp) does work to find the script tag. What now? There are more than 1 tag with the same class. I want them all. But I want only with also one of a list of classes..... Where can I find instructions and demos and limitations of DOM parsers (like the one in http://simplehtmldom.sourceforge.net/)? I need something that will work on, at least, a big amount of free servers.

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  • What should a teen dev do for practical experience in development?

    - by aviraldg
    What should a teen dev do for practical experience? If you want more details , then read on: I learnt programming when I was 9 , with GWBASIC (which I now hate) , which was what was taught @ school. That was done in a month. After that I learnt C++ and relearnt it (as I didn't know of templates and the STL before that) Recently I learnt PHP , SQL and Python. This was around the time I switched over to Ubuntu. I'd always loved the "GNUish" style of software development so I jumped right in. However , most of the projects that I found required extensive knowledge of their existing codebase. So , right now I'm this guy who knows a couple of languages and has written a couple of small programs ... but hasn't gone "big", if you get it. I would love suggestions of projects that are informal and small to medium sized , and do not require much knowledge of the codebase. Also note that I've looked at things like Google Summer of Code and sites like savannah.gnu.org and the first doesn't apply , since I'm still in school and the latter either has infeasable projects , or things that are too hard.

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  • Packages name conflicting with getters and setters?

    - by MrKishi
    Hello, folks. So, I've came across this compilation error a while ago.. As there's an easy fix and I didn't find anything relevant at the time, I eventually let it go. I just remembered it and I'm now wondering if this is really part of the language grammar (which I highly doubt) or if it's a compiler bug. I'm being purely curious about this -- it doesn't really affect development, but it would be nice to see if any of you have seen this already. package view { import flash.display.Sprite; public class Main extends Sprite { private var _view:Sprite = new Sprite(); public function Main() { this.test(); } private function test():void { trace(this.view.x, this.view.y); //1178: Attempted access of inaccessible property x through a reference with static type view:Main. //1178: Attempted access of inaccessible property y through a reference with static type view:Main. //Note that I got this due to the package name. //It runs just fine if I rename the package or getter. } public function get view():Sprite { return this._view; } } }

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  • CSS to create curved corner between two elements?

    - by Tauren
    My UI has an unordered list on the left. When a list item is selected, a div appears on the right of it. I'd like to have a curved outer corner where the <li> and the <div> meet. See the white arrow in the image below. To extend the blue <li> to the edge of the <ul>, I'm planning to do something like this: li { right-margin: 2em; border-radius: 8px; } li.active { right-margin: 0; border-bottom-right-radius: 0; border-top-right-radius: 0; } Is there a better way to extend the <li> to the edge of the <ul>? Obviously, I'll include the webkit and mozilla border radius CSS as well. The main thing I'm unsure about is that outer corner underneath the bottom right corner of the active <li>. I have some ideas, but they seem like hacks. Any suggestions? NOTE that the <ul> is indicated in grey, but it would be white in the real design. Also, I'm planning to use Javascript to position the <div> correctly when an <li> is selected.

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  • C++ member template for boost ptr_vector

    - by Ivan
    Hi there, I'm trying to write a container class using boost::ptr_vector. Inside the ptr_vector I would like to include different classes. I'm trying to achieve that using static templates, but so far I'm not able to do that. For example, the container class is class model { private: boost::ptr_vector<elem_type> elements; public: void insert_element(elem_type *a) { element_list.push_back(a); } }; and what I'm trying to achieve is be able to use different elem_type classes. The code below doesn't satisfy my requirements: template <typename T>class model { private: boost::ptr_vector<T> elements; public: void insert_element(T *a) { element_list.push_back(a); } }; because when I initialize the container class I can only use one class as template: model <elem_type_1> model_thing; model_thing.insert_element(new elem_type_1) but not elem_type_2: model_thing.insert_element(new elem_type_2)//error, of course It is possible to do something like using templates only on the member? class model { private: template <typename T> boost::ptr_vector<T> elements; public: void insert_element(T *a) { element_list.push_back(a); } }; //wrong So I can call the insert_element on the specific class that I want to insert? Note that I do not want to use virtual members. Thanks!

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  • How to detect if a certain range resides (partly) within an other range?

    - by Tom
    Lets say I've got two squares and I know their positions, a red and blue square: redTopX; redTopY; redBotX; redBotY; blueTopX; blueTopY; blueBotX; blueBotY; Now, I want to check if square blue resides (partly) within (or around) square red. This can happen in a lot of situations, as you can see in this image I created to illustrate my situation better: Note that there's always only one blue and one red square, I just added multiple so I didn't have to redraw 18 times. My original logic was simple, I'd check all corners of square blue and see if any of them are inside square red: if ( ((redTopX >= blueTopX) && (redTopY >= blueTopY) && (redTopX <= blueBotX) && (redTopY <= blueBotY)) || //top left ((redBotX >= blueTopX) && (redTopY >= blueTopY) && (redBotX <= blueBotX) && (redTopY <= blueBotY)) || //top right ((redTopX >= blueTopX) && (redBotY >= blueTopY) && (redTopX <= blueBotX) && (redBotY <= blueBotY)) || //bottom left ((redBotX >= blueTopX) && (redBotY >= blueTopY) && (redBotX <= blueBotX) && (redBotY <= blueBotY)) //bottom right ) { //blue resides in red } Unfortunately, there are a couple of flaws in this logic. For example, what if red surrounds blue (like in situation 1)? I thought this would be pretty easy but am having trouble coming up with a good way of covering all these situations.. can anyone help me out here? Regards, Tom

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  • Pointers and Addresses in C

    - by Mohit
    #include "stdio.h" main() { int i=3,*x; float j=1.5,*y; char k='c',*z; x=&i; y=&j; z=&k; printf("\nAddress of x= %u",x); printf("\nAddress of y= %u",y); printf("\nAddress of z= %u",z); x++; y++;y++;y++;y++; z++; printf("\nNew Address of x= %u",x); printf("\nNew Address of y= %u",y); printf("\nNew Address of z= %u",z); printf("\nNew Value of i= %d",i); printf("\nNew Value of j= %f",j); printf("\nNew Value of k= %c\n",k); } Output: Address of x= 3219901868 Address of y= 3219901860 Address of z= 3219901875 New Address of x= 3219901872 New Address of y= 3219901876 New Address of z= 3219901876 New Value of i= 3 New Value of j= 1.500000 New Value of k= c The new address of variable y and z are same. How can two variables have same address and et have different values? Note: I used gcc compiler on Ubuntu 9.04

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  • How do you prove a function works?

    - by glenn I.
    I've recently gotten the testing religion and have started primarily with unit testing. I code unit tests which illustrate that a function works under certain cases, specifically using the exact inputs I'm using. I may do a number of unit tests to exercise the function. Still, I haven't actually proved anything other than the function does what I expect it to do under the scenarios I've tested. There may be other inputs and scenarios I haven't thought of and thinking of edge cases is expensive, particularly on the margins. This is all not very satisfying to do me. When I start to think of having to come up with tests to satisfy branch and path coverage and then integration testing, the prospective permutations can become a little maddening. So, my question is, how can one prove (in the same vein of proving a theorem in mathematics) that a function works (and, in a perfect world, compose these 'proofs' into a proof that a system works)? Is there a certain area of testing that covers an approach where you seek to prove a system works by proving that all of its functions work? Does anybody outside of academia bother with an approach like this? Are there tools and techniques to help? I realize that my use of the word 'work' is not precise. I guess I mean that a function works when it does what some spec (written or implied) states that it should do and does nothing other than that. Note, I'm not a mathematician, just a programmer.

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  • Pattern for version-specific implementations of a Java class

    - by Mike Monkiewicz
    So here's my conundrum. I am programming a tool that needs to work on old versions of our application. I have the code to the application, but can not alter any of the classes. To pull information out of our database, I have a DTO of sorts that is populated by Hibernate. It consumes a data object for version 1.0 of our app, cleverly named DataObject. Below is the DTO class. public class MyDTO { private MyWrapperClass wrapper; public MyDTO(DataObject data) { wrapper = new MyWrapperClass(data); } } The DTO is instantiated through a Hibernate query as follows: select new com.foo.bar.MyDTO(t1.data) from mytable t1 Now, a little logic is needed on top of the data object, so I made a wrapper class for it. Note the DTO stores an instance of the wrapper class, not the original data object. public class MyWrapperClass { private DataObject data; public MyWrapperClass(DataObject data) { this.data = data; } public String doSomethingImportant() { ... version-specific logic ... } } This works well until I need to work on version 2.0 of our application. Now DataObject in the two versions are very similar, but not the same. This resulted in different sub classes of MyWrapperClass, which implement their own version-specific doSomethingImportant(). Still doing okay. But how does myDTO instantiate the appropriate version-specific MyWrapperClass? Hibernate is in turn instantiating MyDTO, so it's not like I can @Autowire a dependency in Spring. I would love to reuse MyDTO (and my dozens of other DTOs) for both versions of the tool, without having to duplicate the class. Don't repeat yourself, and all that. I'm sure there's a very simple pattern I'm missing that would help this. Any suggestions?

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  • How might a C# programmer approach writing a solution in javascript?

    - by Ben McCormack
    UPDATE: Perhaps this wasn't clear from my original post, but I'm mainly interested in knowing a best practice for how to structure javascript code while building a solution, not simply learning how to use APIs (though that is certainly important). I need to add functionality to a web site and our team has decided to approach the solution using a web service that receives a call from a JSON-formatted AJAX request from within the web site. The web service has been created and works great. Now I have been tasked with writing the javascript/html side of the solution. If I were solving this problem in C#, I would create separate classes for formatting the request, handling the AJAX request/response, parsing the response, and finally inserting the response somehow into the DOM. I would build properties and methods appropriately into each class, doing my best to separate functionality and structure where appropriate. However, I have to solve this problem in javascript. Firstly, how could I approach my solution in javascript in the way I would approach it from C# as described above? Or more importantly, what's a better way to approach structuring code in javascript? Any advice or links to helpful material on the web would be greatly appreciated. NOTE: Though perhaps not immediately relevant to this question, it may be worth noting that we will be using jQuery in our solution.

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