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  • Why doesn't is operator take in consideration if the explicit operator is overriden when checking ty

    - by Galilyou
    Hey Guys, Consider this code sample: public class Human { public string Value { get; set;} } public class Car { public static explicit operator Human (Car c) { Human h = new Human(); h.Value = "Value from Car"; return h; } } public class Program { public static void Mani() { Car c = new Car(); Human h = (Human)c; Console.WriteLine("h.Value = {0}", h.Value); Console.WriteLine(c is Human); } } Up I provide a possibility of an explicit cast from Car to Human, though Car and Human hierarchically are not related! The above code simply means that "Car is convertible to human" However, if you run the snippet you will find the expression c is Human evaluates to false! I used to believe that the is operator is kinda expensive cause it attempts to do an actual cast that might result in an InvalidCastException. If the operator is trying to cast, then the cast should succeed as there's an operator logic that should perform the cast! What does "is" test? Does test a hierarchical "is-a" relationship? Does test whether a variable type is convertible to a type?

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  • (x86) Assembler Optimization

    - by Pindatjuh
    I'm building a compiler/assembler/linker in Java for the x86-32 (IA32) processor targeting Windows. High-level concepts of a "language" (in essential a Java API for creating executables) are translated into opcodes, which then are wrapped and outputted to a file. The translation process has several phases, one is the translation between languages: the highest-level code is translated into the medium-level code which is then translated into the lowest-level code (probably more than 3 levels). My problem is the following; if I have higher-level code (X and Y) translated to lower-level code (x, y, U and V), then an example of such a translation is, in pseudo-code: x + U(f) // generated by X + V(f) + y // generated by Y (An easy example) where V is the opposite of U (compare with a stack push as U and a pop as V). This needs to be 'optimized' into: x + y (essentially removing the "useless" code) My idea was to use regular expressions. For the above case, it'll be a regular expression looking like this: x:(U(x)+V(x)):null, meaning for all x find U(x) followed by V(x) and replace by null. Imagine more complex regular expressions, for more complex optimizations. This should work on all levels. What do you suggest? What would be a good approach to optimize in these situations?

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  • getting an error on jslint while creating a new object using javascript

    - by user3712689
    For some reason this code is giving a lint. I can't really figure out why. It says: 'was expecting a assignment or function call, and instead saw an expression.' What does that mean? window.onload = function (){ function SuspectOne (naam, leeftijd, wie){ this.naam = Spencer Hawes; this.leeftijd = 22; this.wie = zoon van de man; } function SuspectTwo (naam, leeftijd, wie){ this.naam = Tyrone Biggums; this.leeftijd = 28; this.wie = lokale herionejunk; } function SuspectThree (naam, leeftijd, wie){ this.naam = Ellie Campbell Hawes; this.leeftijd = 40; this.wie = vrouw van de man; } var verdachten = new Array[]; verdachten[0] = new Verdachte("Spencer Hawes", 22, "zoon van de man"); verdachten[1] = new Verdachte("Tyrone Biggums", 28, "lokale herionejunk"); verdachten[2] = new Verdachte("Ellie Spencer Hawes", 40, "vrouw van de man"); for(x=0; x<verdachten.length; x++){ console.log("De verdachte is de " + verdachten[x].leeftijd + "jaar oud " + verdachten[x].naam + ", de " + verdachten[x].wie); } }; Can someone help me with this? I would really like a lint free code.

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  • Conventions for the behavior of double or triple "click to select text" features?

    - by John Sullivan
    Almost any mature program that involves text implements "double click to select the word" and, in some cases, "triple click to select additional stuff like an entire line" as a feature. I find these features useful but they are often inconsistent between programs. Example - some programs' double clicks do not select the ending space after a word, but most do. Some recognize the - character as the end of a word, others do not. SO likes to select the entire paragraph as I write this post when I triple click it, VS web developer 2005 has no triple click support, and ultra-edit 32 will select one line upon triple clicking. We could come up with innumerable inconsistencies about how double and triple click pattern matching is implemented across programs. I am concerned about how to implement this behavior in my program if nobody else has achieved a convention about how the pattern matching should work. My question is, does a convention (conventions? maybe an MS or Linux convention?) exist that dictates how these features are supposed to behave to the end user? What, if any, are they?

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  • Culture Sensitive GetHashCode

    - by user114928
    Hi, I'm writing a c# application that will process some text and provide basic query functions. In order to ensure the best possible support for other languages, I am allowing the users of the application to specify the System.Globalization.CultureInfo (via the "en-GB" style code) and also the full range of collation options using the System.Globalization.CompareOptions flags enum. For regular string comparison I'm then using a combination of: a) String.Compare overload that accepts the culture and options b) For some bulk processes I'm caching the byte data (KeyData) from CompareInfo.GetSortKey (overload that accepts the options) and using a byte-by-byte comparison of the KeyData. This seemed fine (although please comment if you think these two methods shouldn't be mixed), but then I had reason to use the HashSet< class which only has an overload for IEqualityComparer<. MS documentation seems to suggest that I should use StringComparer (which implements both IEqualityComparer< and IComparer<), but this only seems to support the "IgnoreCase" option from CompareOptions and not "IgnoreKanaType", "IgnoreSymbols", "IgnoreWidth" etc. I'm assuming that a StringComparer that ignores these other options could produce different hashcodes for two strings that might be considered the same using my other comparison options. I'd therefore get incorrect results from my application. Only thought at the moment is to create my own IEqualityComparer< that generates a hashcode from the SortKey.KeyData and compares eqality be using the String.Compare overload. Any suggestions?

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  • Java: 2-assignments-2-initializations inside for-loop not allowed?

    - by HH
    $ javac MatchTest.java MatchTest.java:7: ')' expected for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ MatchTest.java:7: ';' expected for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ MatchTest.java:7: ';' expected for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ MatchTest.java:7: not a statement for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ MatchTest.java:7: illegal start of expression for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ 5 errors $ cat MatchTest.java import java.util.*; import java.io.*; public class MatchTest { public static void main(String[] args){ String text = "hello0123456789hello0123456789hello1234567890hello3423243423232"; for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) System.out.println(i); } }

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  • Ruby 1.9 GarbageCollector, GC.disable/enable

    - by seb
    I'm developing a Rails 2.3, Ruby 1.9.1 webapplication that does quite a bunch of calculation before each request. For every request it has to calculate a graph with 300 nodes and ~1000 edges. The graph and all its nodes, edges and other objects are initialized for every request (~2000 objects) - actually they are cloned from an uncalculated cached graph using Marshal.load(Marshal.dump()). Performance is quite an issue here. Right now the whole request takes in average 150ms. I then saw that during a request, parts of the calculation randomly take longer. Assuming, that this might be the GarbageCollector kicking in, I wrapped the request in GC.disable and GC.enable, so that the request waits with garbagecollecting until calculating and rendering have finished. def query GC.disable calculate respond_to do |format| format.html {render} end GC.enable end The average request now takes about 100ms (50 ms less). But I'm unsure if this is a good/stable solution, I assume there must be drawbacks doing that. Does anybody has experience with a similar problem or sees problems with the above code?

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  • How to publish internal data to the internet - as simple as possible

    - by mlarsen
    We have a .net 2-tier application where a desktop program is talking to a database. We support MS SQL Server 2000, 2005, 2008 and Oracle 9, 10 and 11. The application is sold, not as shrink-wrap, but pretty close. It is quite important for us that the installation and configuration is as easy as possible as installation instructions are usually supplied in written form to the customers internal IT-department. Our application is usually not seen as mission critical for the IT-department, so we need to keep their work down to a minimum. Now we are starting to get wishes for a web application build on top of the same data. The web application will be hosted by us and delivered as a SaaS application. Now the challenge is how to move data back and forth between the web application and the customers internal database. as I see it we have some requirements: We must be ready to handle the situation where the customers database is not accessible from the DMZ. I guess the easiest solution is that all communication is initiated from inside the customers lan. As little firewall configuration as possible. The best is if we can run without any special configuration as long as outgoing traffic from the customers lan are not blocked. If we need something changed in the firewall, we must be able to document that the change is secure. It doesn't have to be real time. Moving data in batches every ten minutes or so is OK. Data moves both ways, but not the same tables, so we don't have to support merges. It would be nice if we don't have to roll our own framework completely. Looking forward to hear your suggestions.

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  • I need to remove Java Script tags using regular expressions and JRegex

    - by piotr
    I need to remove all the Java Script tags and the content in between and style tags from the HTML code of web pages.So far I've come up with this expression : "(<[ \r\n\t]script([ \r\n\t]|){1,}([ \r\n\t]|.)?)|(<[ \r\n\t]noscript([ \r\n\t]|){1,}([ \r\n\t]|.)?)|(<[ \r\n\t]style([ \r\n\t]|){1,}([ \r\n\t]|.)?)" I use JRegex library to work with regular expressions. When I test it in any regex tester it works just fine, but once I run my program - it all crashes down with this error report: Exception in thread "Thread-0" java.lang.StackOverflowError at java.util.regex.Pattern$BranchConn.match(Unknown Source) at java.util.regex.Pattern$BmpCharProperty.match(Unknown Source) at java.util.regex.Pattern$Branch.match(Unknown Source) at java.util.regex.Pattern$GroupHead.match(Unknown Source) at java.util.regex.Pattern$LazyLoop.match(Unknown Source) at java.util.regex.Pattern$GroupTail.match(Unknown Source) at java.util.regex.Pattern$BranchConn.match(Unknown Source) at java.util.regex.Pattern$CharProperty.match(Unknown Source) at java.util.regex.Pattern$Branch.match(Unknown Source) at java.util.regex.Pattern$GroupHead.match(Unknown Source) at java.util.regex.Pattern$LazyLoop.match(Unknown Source) .................................. And it keeps on going forever. If anyone can give me an advice on this one - I'll be very grateful.

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  • Operation is not valid due to the current state of the object?

    - by Bill
    I am programming in C#; the code was working about a week ago, however it throws an exception and I don't understand at all what could be wrong with it. Var root = new CalculationNode(); -> Throw exception. In the call stack thats the only thing listed, I've been told that it could be that I need a clean build, but I am open to any ideas or suggestions. Thanks, -Bill Update: Exception's Detail System.InvalidOperationException was unhandled by user code Message=Operation is not valid due to the current state of the object. Source=Calculator.Logic StackTrace: at ~.Calculator.Logic.MyBaseExpressionParser.Parse(String expression) in ~\Source\Calculator.Logic\MyBaseExpressionParser.cs:line 44 at ~.Calculator.Logic.Tests.MyBaseCalculatorServiceTests.BasicMathDivision() in ~\Projects\Tests\Calculator.Logic.Tests\MyBaseCalculatorServiceTests.cs:line 60 InnerException: CalculationNode's code: public sealed calss CalculationNode { public CalculationNode() { this.Left = null; this.Right = null; this.Element = new CalculationElement(); } public CalculationNode Left {get;set;} public CalculationNode Right {get;set;} public CalculationElement Element {get; set;} } CalculationElement's code: public sealed class CalculationElement { public CalculationElement() { Value = string.Empty; IsOperator = false; } public string Value {get; set} public bool IsOperator {get; set} }

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  • How to update application files using patching?

    - by Marek
    I am not interested in any auto update solution, such as ClickOnce or the MS Updater Block. For anyone feeling the urge to ask why not: I am already using these and there is nothing wrong with them, I would just like to learn about any efficient alternatives. I would like to publish patches = small differences that will modify existing files of the deployment with the smallest possible delta. Not only code needs to be patched, but also resource files. Patching the running code can be accomplished by maintaining two separate synchronized copies of the deployment (no on the fly changes to the running executable are required). The application itself can be xcopy deployed (to avoid MSI auto-correcting the modified files or breaking ClickOnce signatures). I would like to learn how to handle different versions of patches (e.g. there is a patch issued that fixes one error and later another patch that fixes another error (in the same file) - users may have any combination of these and there comes a third patch - in text files, this may be easy to implement, but how about executable files? (native Win32 code vs. .NET, any difference?) If the first problem is too hard to solve or unsolvable for executables, I would like to at least learn if there is a solution that implements simple patching with serial revisions - in order to install revision 5, user must have all previous revisions installed to ensure validity of the deployment. Are there any existing solutions to accomplish this? NOTE: There are a few questions on SO that may seem like duplicates, but none with a good answer. This question is about the Windows platform, preferably .NET.

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  • Tal condition always evaluates to false

    - by Ander2
    I'm using plone and trying to display a form result in a page template. I'm trying to filter some database results using tal:condition with a python expression but it always evaluates to false. The code looks like this: <tr tal:repeat="result view/results"> <td> <span tal:condition="python:view.teams[0]==result.team_id" tal:replace="result/position">Position</span></td> <td> <span tal:condition="python:view.teams[1]==result.team_id" tal:replace="result/position">Position</span></td> </tr> I want the table cells to be filled with the team position when the team id is matched in the result, but the cells always are empty. If I remove the tal:condition from the span and replace the tal:replace="result/position" with tal:replace=python:view.teams[0]==result.team_id it prints True or False so I can check that the result is correct. Can anyone help me about this issue? Why does tal:condition allways evaluate false?

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  • Simple jQuery code contains a syntax error that I can't find

    - by inkedmn
    I've got this (remarkably) simple JavaScript function that is called when a user clicks a "Cancel" link: function hideNewUserPanel(){ $('#create_user_panel').slideUp('slow'); $('.right_interior_panel').slideDown('slow'); } And the code to add the handler: $(function(){ $('#cancel_create_user_btn').live('click', function(){ hideNewUserPanel(); } }); Functionally, everything works as expected. Trouble is, when I click the "Cancel" link, Firebug shows an error in the console: uncaught exception: Syntax error, unrecognized expression: # I've stepped through the code several times and the error appears at some point before the call to hideNewUserPanel(). At the risk of sounding like one of "those programmers" (the kind that claim to have found a bug in GCC and assume their own code is perfect), the exception is being thrown from somewhere within jQuery proper, so I assume the issue is in there. I'm using jQuery 1.3.2 (this is a legacy project using many jQuery plugins that will break if we update to 1.4.x). Is there anything obviously wrong with my code that I'm simply not seeing? This code is, frankly, very simple and I don't really see what the issue could be. Thanks!

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  • How do I get rid of these warnings?

    - by Brian Postow
    This is really several questions, but anyway... I'm working with a big project in XCode, relatively recently ported from MetroWorks (Yes, really) and there's a bunch of warnings that I want to get rid of. Every so often an IMPORTANT warning comes up, but I never look at them because there's too many garbage ones. So, if I can either figure out how to get XCode to stop giving the warning, or actually fix the problem, that would be great. Here are the warnings: It claims that <map.h> is antiquated. However, when I replace it with <map> my files don't compile. Evidently, there's something in map.h that isn't in map... this decimal constant is unsigned only in ISO C90 This is a large number being compared to an unsigned long. I have even cast it, with no effect. enumeral mismatch in conditional expression: <anonymous enum> vs <anonymous enum> This appears to be from a ?: operator. Possibly that the then and else branches don't evaluate to the same type? Except that in at least one case, it's (matchVp == NULL ? noErr : dupFNErr) And since those are both of type OSErr, which is mac defined... I'm not sure what's up. It also seems to come up when I have other pairs of mac constants... multi-character character constant This one is obvious. The problem is that I actually NEED multi-character constants... -fwritable-strings not compatible with literal CF/NSString I unchecked the "Strings are Read-Only" box in both the project and target settings... and it seems to have had no effect...

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  • animated swap position of two buttons

    - by Jagat
    I am trying to swap the position of two buttons. my swapping code looks as below. private void exchangeButtons(Button btn1, Button btn2) { // Create the animation set AnimationSet exchangeAnimation = new AnimationSet(true); TranslateAnimation translate = new TranslateAnimation( Animation.RELATIVE_TO_SELF, btn2.getLeft(), Animation.RELATIVE_TO_SELF, btn1.getLeft(), Animation.RELATIVE_TO_SELF, btn2.getRight(), Animation.RELATIVE_TO_SELF, btn1.getRight() ); translate.setDuration(500); exchangeAnimation.addAnimation(translate); // int fromX = btn1.getLeft(); // int fromY = btn1.getRight(); // int toX = btn2.getLeft(); // int toY = btn2.getRight(); Log.d("ArrangeMe", "view1 pos:" + btn1.getLeft() + ", " +btn1.getRight() + "view2 pos:" + btn2.getLeft() + ", " + btn2.getRight()); AnimationSet exchangeAnimation1 = new AnimationSet(true); TranslateAnimation translate1 = new TranslateAnimation( Animation.RELATIVE_TO_SELF, btn1.getLeft(), Animation.RELATIVE_TO_SELF, btn2.getLeft(), Animation.RELATIVE_TO_SELF, btn1.getRight(), Animation.RELATIVE_TO_SELF, btn2.getRight() ); translate1.setDuration(500); exchangeAnimation1.addAnimation(translate1); // EXECUTE btn1.startAnimation(exchangeAnimation); btn2.startAnimation(exchangeAnimation1); } I call the code as below exchangeButtons(button1, button2); my layout looks as below what happens when i execute the code is, instead of the buttons exchanging their positions, they just disappear for sometime[may be 500 ms] and reappear as they were originally. how to resolve this problem ? will it work properly in device ? regards

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  • Regex for removing certain variable numeric values from some text

    - by stephemurdoch
    I want to substitute all 4 instances of the number 300 from the code below, with 470. <div> <object width="300" height="300"> <embed src="link-removed" width="300" height="300"></embed> </object> <p> <a href="another-link">link</a> </p> </div> The width and height of the code being pasted might not always be 300 by 300. So I figure I probably need a regular expression that subs any numeric value that follows the strings "width=" and "height=", whilst remembering to account for the quotations marks that surround the number. Can anyone tell me if that's the best way, and if so, what would be the best regex? In case it matters, the code being pasted is stored as "text" in the db rather than as a string, as it's quite lengthy (i've removed a few hundred chars from what you see pasted here)...

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  • Microsoft products such as Visual Studio 2010 does not require to enter serial number

    - by MainMa
    Hi, I am member of WebsiteSpark and was member of DreamSpark. Both programs enable to download software and provide serial keys to use. Some software like Windows Server has an ISO file to download and a serial number displayed on the website which I must enter during installation. Some other software does not have any serial key. For example, when I downloaded Visual Studio 2010, there was just a link to an ISO file. During installation, there was no such a field as serial number (whereas Visual Studio 2008 had this field at the beginning of installation process). There is the same thing with SQL Server 2008 and Microsoft Expression Studio 3. Even when I've downloaded the public trial RTM version of Windows Seven Enterprise, there were no serial number to enter. I don't think that such expensive products as SQL Server 2008 Enterprise are delivered without serials and online validation, so I suppose that the serial is embedded into the product itself, either in installation binaries or in a separate config file, so is already in the ISO I download so I do not have to enter it. So my question is, how it is done technically? Is each 2 GBs ISO generated on-demand on the server to embed a serial each time this ISO is requested? I suppose that if it is done, it has a huge impact on servers performance (no caching, no streaming...), so what may be the techniques used behind? I want to implement the same feature in a product I intend to ship (to simplify installation by avoiding to ask to enter serial number), but I really don't see how to do it with low impact on server performance.

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  • Please take a stab at this VB.Net Oracle-related sample and help me with String.Format.

    - by Hamish Grubijan
    If the database is not Oracle, it is MS SQl 2008. My task: if Oracle, add two more parameters when calling a stored proc. Oracle and MSFT stored procs are generated; Oracle ones have 3 extra parameters: Vret_val out number, Vparam2 in out number, Vparam3 in out number, ... the rest (The are not actually named Vparam2 and Vparam3, but this should not matter). So, the code for a helper VB.Net class that calls a stored proc: Imports System.Data.Odbc Imports System.Configuration Dim objCon As OdbcConnection = Nothing Dim objAdapter As OdbcDataAdapter Dim cmdCommand As New OdbcCommand Dim objDataTable As DataTable Dim sconnection As String Try sconnection = mConnectionString objAdapter = New OdbcDataAdapter objCon = New OdbcConnection(sconnection) objCon.Open() objAdapter.SelectCommand = cmdCommand objAdapter.SelectCommand.Connection = objCon objAdapter.SelectCommand.CommandType = CommandType.StoredProcedure objAdapter.SelectCommand.CommandTimeout = Globals.mReportTimeOut If Not mIsOracle Then objAdapter.SelectCommand.CommandText = String.Format("{{call {0}}}", spName) Else Dim returnValue As New OdbcParameter returnValue.Direction = ParameterDirection.Output returnValue.ParameterName = "@Vret_val" returnValue.OdbcType = OdbcType.Numeric objAdapter.SelectCommand.Parameters.Add(returnValue) objAdapter.SelectCommand.CommandText = String.Format("{{call {0}(?)}}", spName) End If Try objDataTable = New DataTable(spName) objAdapter.Fill(objDataTable) Catch ex As Exception ... Question: I am puzzled as to what String.Format("{{call {0}(?)}}", spName) does, in particular the (?) part. My understanding of the String.Format is that it will simply replace {0} with spName. The {{, }}, and (?) do throw me off because { reminds me of formatting, (?) hints at some advanced regex use. Unfortunately I am getting little help from a key person who is on vacation without a leash [smart]phone. I am guessing that I simply add 5 more lines for each additional parameter, and change String.Format("{{call {0}(?)}}", spName) to String.Format("{{call {0}(?,?,?)}}", spName). I forgot to mention that I am coding this "blindly" - I have a compiler to help me, but no environment set up to test this. This will be over in a few days, but I need to do my best to try finishing it on time :) Thanks.

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  • Bind button visibility to the expresion (C#)

    - by drasto
    I have a delete button in each row of GridView (component ASP.NET). I want some of the delete buttons to be invisible. The visibility of the delete button should depend on the data that are back the row. GridView is backed by EntityDataSource. GridView displays entities called Category, one instance in each row. Entity Category has (besides others) also a field of type EntityCollection. Name of that field is Items. Basically I want to allow user to delete a row only if the Items field of backing Category entity is an empty collection. I cannot make up the binding of Visible property. I have no experience with bindings and Google does not really help. This is how the button looks right now: <asp:Button ID="DeleteButton" runat="server" CommandName="Delete" Text="Delete" Visible=??? ></asp:Button> I don't know what should replace ???. The button schold be visible only when this expression evaluates to true: ((SimpleEShop.Model.Category) dataItem).Items.LongCount() <= 0 where dataItem variable contains data of current row in the table. What is the binding that I need ?

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  • Solving Naked Triples in Sudoku

    - by Kave
    Hello, I wished I paid more attention to the math classes back in Uni. :) How do I implement this math formula for naked triples? Naked Triples Take three cells C = {c1, c2, c3} that share a unit U. Take three numbers N = {n1, n2, n3}. If each cell in C has as its candidates ci ? N then we can remove all ni ? N from the other cells in U.** I have a method that takes a Unit (e.g. a Box, a row or a column) as parameter. The unit contains 9 cells, therefore I need to compare all combinations of 3 cells at a time that from the box, perhaps put them into a stack or collection for further calculation. Next step would be taking these 3-cell-combinations one by one and compare their candidates against 3 numbers. Again these 3 numbers can be any possible combination from 1 to 9. Thats all I need. But how would I do that? How many combinations would I get? Do I get 3 x 9 = 27 combinations for cells and then the same for numbers (N)? How would you solve this in classic C# loops? No Lambda expression please I am already confused enough :) Many Thanks for any help,

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  • Extension methods for encapsulation and reusability

    - by tzaman
    In C++ programming, it's generally considered good practice to "prefer non-member non-friend functions" instead of instance methods. This has been recommended by Scott Meyers in this classic Dr. Dobbs article, and repeated by Herb Sutter and Andrei Alexandrescu in C++ Coding Standards (item 44); the general argument being that if a function can do its job solely by relying on the public interface exposed by the class, it actually increases encapsulation to have it be external. While this confuses the "packaging" of the class to some extent, the benefits are generally considered worth it. Now, ever since I've started programming in C#, I've had a feeling that here is the ultimate expression of the concept that they're trying to achieve with "non-member, non-friend functions that are part of a class interface". C# adds two crucial components to the mix - the first being interfaces, and the second extension methods: Interfaces allow a class to formally specify their public contract, the methods and properties that they're exposing to the world. Any other class can choose to implement the same interface and fulfill that same contract. Extension methods can be defined on an interface, providing any functionality that can be implemented via the interface to all implementers automatically. And best of all, because of the "instance syntax" sugar and IDE support, they can be called the same way as any other instance method, eliminating the cognitive overhead! So you get the encapsulation benefits of "non-member, non-friend" functions with the convenience of members. Seems like the best of both worlds to me; the .NET library itself providing a shining example in LINQ. However, everywhere I look I see people warning against extension method overuse; even the MSDN page itself states: In general, we recommend that you implement extension methods sparingly and only when you have to. So what's the verdict? Are extension methods the acme of encapsulation and code reuse, or am I just deluding myself?

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  • Elegant way of parsing Data files for Simulation

    - by sc_ray
    I am working on this project where I need to read in a lot of data from .dat files and use the data to perform simulations. The data in my .dat file looks as follows: DeviceID InteractingDeviceID InteractionStartTime InteractionEndTime 1 2 1101 1105 1,2 1101 and 1105 are tab delimited and it means Device 1 interacted with Device 2 at 1101 ms and ended the interaction at 1105ms. I have a trace data sets that compile thousands of such interactions and my job is to analyze these interactions. The first step is to parse the file. The language of choice is C++. The approach I was thinking of taking was to read the file, for every line that's read create a Device Object. This Device object will contain the property DeviceId and an array/vector of structs, that will contain a list of all the devices the given DeviceId interacted with over the course of the simulation.The struct will contain the Interacting Device Id, Interaction Start Time and Interaction End Time. I have a two fold question here: Is my approach correct? If I am on the right track, how do I rapidly parse these tab delimited data files and create Device objects without excessive memory overhead using C++? A push in the right direction will be much appreciated. Thanks

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  • Why doesn't this simple regex match what I think it should?

    - by Kevin Stargel
    I have a data file that looks like the following example. I've added '%' in lieu of \t, the tab control character. 1234:56% Alice Worthington alicew% Jan 1, 2010 10:20:30 AM% Closed% Development Digg: Reddit: Update%% file-one.txt% 1.1% c:/foo/bar/quux Add%% file-two.txt% 2.5.2% c:/foo/bar/quux Remove%% file-three.txt% 3.4% c:/bar/quux Update%% file-four.txt% 4.6.5.3% c:/zzz ... many more records of the above form The records I'm interested in are the lines beginning with "Update", "Add", "Remove", and so on. I won't know what the lines begin with ahead of time, or how many lines precede them. I do know that they always begin with a string of letters followed by two tabs. So I wrote this regex: generate-report-for 1234:56 | egrep "^[[:alpha:]]+\t\t.+" But this matches zero lines. Where did I go wrong? Edit: I get the same results whether I use '...' or "..." for the egrep expression, so I'm not sure it's a shell thing.

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  • Ditching Django's models for Ajax/Web Services

    - by Igor Ganapolsky
    Recently I came across a problem at work that made me rethink Django's models. The app I am developing resides on a Linux server. Its a simple model/view/controller app that involves user interaction and updating data in the database. The problem is that this data resides in a MS SQL database on a Windows machine. So in order to use Django's models, I would have to leverage an ODBC driver on linux, and the use a python add-on like pyodbc. Well, let me tell you, setting up a reliable and functional ODBC connection on linux is no easy feat! So much so, that I spent several hours maneuvering this on my CentOS with no luck, and was left with frustration and lots of dumb system errors. In the meantime I have a deadline to meet, and suddenly the very agile and rapid Django application is a roadblock rather than a pleasure to work with. Someone on my team suggested writing this app in .NET. But there are a few problems with that: it won't be deployable on a linux machine, and I won't be able to work on it since I don't know ASP.net. Then a much better suggestion was made: keep the app in django, but instead of using models, do straight up ajax/web services calls in the template. And then it dawned on me - what a great idea. Django's models seem like a nuissance and hindrance in this case, and I can just have someone else write .Net services on their side, that I can call from my template. As a result my app will be leaner and more compact. So, I was wondering if you guys ever came across a similar dillema and what you decided to do about it.

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  • Improving the performance of XSL

    - by Rachel
    I am using the below XSL 2.0 code to find the ids of the text nodes that contains the list of indices that i give as input. the code works perfectly but in terms for performance it is taking a long time for huge files. Even for huge files if the index values are small then the result is quick in few ms. I am using saxon9he Java processor to execute the XSL. <xsl:variable name="insert-data" as="element(data)*"> <xsl:for-each-group select="doc($insert-file)/insert-data/data" group-by="xsd:integer(@index)"> <xsl:sort select="current-grouping-key()"/> <data index="{current-grouping-key()}" text-id="{generate-id( $main-root/descendant::text()[ sum((preceding::text(), .)/string-length(.)) ge current-grouping-key() ][1] )}"> <xsl:copy-of select="current-group()/node()"/> </data> </xsl:for-each-group> </xsl:variable> In the above solution if the index value is too huge say 270962 then the time taken for the XSL to execute is 83427ms. In huge files if the index value is huge say 4605415, 4605431 it takes several minutes to execute. Seems the computation of the variable "insert-data" takes time though it is a global variable and computed only once. Should the XSL be addessed or the processor? How can i improve the performance of the XSL.

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