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• In C# should I use uint or int for values that are never supposed to be negative?

  - by Hamish Grubijan

  Suppose that the MaxValue of (roughly :) ) 2^31 vs 2^32 does not matter. On one hand, using uint seems nice because it is self-explanatory, it indicates (and promises?) that some value may never be negative. However, int is more common, and a cast is often inconvenient. One can just use int and always supplement it with code contracts (everyone has moved to .Net 4.0 by now, right?) Standard libraries do use int for Length and Size properties, even though those should never be negative. So, is it obvious to you that int is better than uint most of the time, or is it more complicated? Please ask questions if you find that this question is not clearly stated. Thanks.

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• Best calculator software to help programmers

  - by RHaguiuda

  As a embedded systems programmer I always need to make lots of base conversions (dec to hex, hex to bin and so on...), and I must admit: Windows 7 calculator is a good calc, but too limited in my point of view. I work a lot with communications protocols and it`s common to need some base conversion in this field of knowledge. I`m looking for a calculator software (not a hardware one), to help with base conversions, but it must also support scientific calc. Can anyone help on this? Since this subject is intended to help programmers, I did not ask this in SuperUser.com. Thanks.

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• Java Jersey RESTful services

  - by pHk

  Rather new to REST and Jersey, and I'm trying out some basic examples. I've got one particular question though, which I haven't really found an answer for yet (don't really know how to look for this): how would you go about storing/defining common services so that they are stateful and accessible to all/some resources? For instance, a logger instance (Log4J or whatever). Do I have to manually initialize this and store it in the HttpSession? Is there a "best practice" way of doing this so that my logger is accessible to all/some resources? Thanks a lot.

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• What are the rules for Javascript's automatic semicolon insertion?

  - by T.R.

  Well, first I should probably ask if this is browser dependent. I've read that if an invalid token is found, but the section of code is valid until that invalid token, a semicolon is inserted before the token if it is preceded by a line break. However, the common example cited for bugs caused by semicolon insertion is: return _a+b; which doesn't seem to follow this rule, since _a would be a valid token. On the other hand, breaking up call chains works as expected: $('#myButton') .click(function(){alert("Hello!")}); Does anyone have a more in-depth description of the rules?

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• ESS/AucTeX/Sweave integration

  - by aL3xa

  I'm using GNU/Linux distro (Arch, if that's relevant), Emacs v23.2.1, ESS v5.9 and AucTeX v11.86. I want to setup AucTeX to recognize .Rnw files, so I can run LaTeX on .Rnw files with C-c C-c and get .dvi file automatically. I reckon it's quite manageable by editing .emacs file, but I still haven't got a firm grasp on Elisp. Yet another problem is quite annoying - somehow, LaTeX is not recognizing \usepackage{Sweave} in preambule, so I actually need to copy Sweave.sty file (in my case located in /usr/share/R/texmf/Sweave.sty) to directory where .Rnw file is located (and I'm getting more frustrated with the fact that this is common bug on Windows platforms!) My question boils down to two problems: how to make LaTeX recognize \usepackage{Sweave} (without copying Sweave.sty to "home" folder each time) how to setup AucTeX to compile .Rnw files to .dvi

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• Bejeweled Blitz - How does it assert there is always a move?

  - by EvilTeach

  I have been playing Bejeweled Blitz for a while now. Yes, it is an addiction. In thinking about the game, I have observed that on some boards, the bottom runs dry (no moves) leaving only the top part of the board playable. Frequently that part of the board drys up, and one is left with moves in area cleared by the last move. The board never runs completely dry, so clearly the program is doing some sorts of calculation that allows it to choose what to drop to prevent it from running dry. I have noticed in this 'mode' that it is very common for the algorithm to drop jewels which causes more non-dry area to appear in the horizontal area. Perhaps less frequent is a drop which seems designed to open up the bottom part of the board again. So my question is "How would one go about designing an algorithm guarantee that there is always a move available.?"

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• Are all languages used within .net Equally performant?

  - by WeNeedAnswers

  I know the "Sales pitch" answer is yes to this question, but is it technically true. The Common Language Runtime (CLR) is designed as an intermediate language based on Imperative Programming (IP), but this has obvious implications when dealing with Declarative Programming (DP). So how efficient is a language based on a different paradigm than the Imperative Style when implemented in the CLR? I also get the feeling that the step to DP would incur an extra level of abstraction that might not model at all performant, would this be a fair comment? I have done some simple tests using F# and it all looks great, but am I missing something if the programs get more complex?

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• Django, Redirecting staff from login to the admin site.

  - by Francisco Gomez

  So my site basically has 2 kinds of ways to login, one of them is for the common users, who get the regular screen that asks them for username and password, the other way its for staff. The staff login should redirect them to the admin site after logging in, but for some reason the redirect doesnt happen, it stays on the same login page. I use this condition on the login view. if user is not None and user.is_active and user.is_staff: auth.login(request,user) return HttpResponseRedirect("/admin/") The admin site its up and running in my url configuration and everything, but i dont know if this is the correct way to redirect to the admin site already on session. Thanks, any help would be appreciated.

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• Correct way to detect sequence parameter?

  - by noamtm

  I want to write a function that accepts a parameter which can be either a sequence or a single value. The type of value is str, int, etc., but I don't want it to be restricted to a hardcoded list. In other words, I want to know if the parameter X is a sequence or something I have to convert to a sequence to avoid special-casing later. I could do type(X) in (list, tuple) but there may be other sequence types I'm not aware of, and no common base class. -N. Edit: See my "answer" below for why most of these answers don't help me. Maybe you have something better to suggest.

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• Can you use the PackageMaker command to create an installer from a list of files?

  - by zekel

  I want to (periodically and automatically) create an installer from various files and folders that are in many places. But, I can't figure out how to supply the packagemaker command with all the paths of the items I want to install. This is for internal development purposes, not for customer distribution. I want the files included to be configureable; it's not really an option to use the GUI to add all the paths because they will change frequently. The best I could do was to use the --watch flag and touch all of the stuff I wanted included in the package. This is very messy and includes other files that happen to be accessed at the same time. There isn't a common scheme to what I want to include, so I can't just --filter the rest out. Is there a better way? Am I missing the point?

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• DataAdapter Select string from base table schema?

  - by MattSlay

  When I built my .xsd, I had to choose the columns for each table, and it made a schema for the tables, right? So how can I get that Select string to use as a base Select command for new instances of dataadapters, and then just append a Where and OrderBy clause to it as needed? That would keep me from having to keep each DataAdapter's field list (for the same table) in synch with the schema of that table in the .xsd file. Isn't it common to have several DataAdapters that work on a certain table schema, but with different params in the Where and OrderBy clauses? Surely one does not have to maintain (or even redundently build) the field list part of the Select strings for half a dozen DataAdapters that all work off of the same table schema. I'm envisioning something like this pseudo code: BaseSelectString = MyTypedDataSet.JobsTable.GetSelectStringFromSchema() // Is there such a method or technique? WhereClause = " Where SomeField = @Param1 and SomeOtherField = @Param2" OrderByClause = " Order By Field1, Field2" SelectString=BaseSelectString + WhereClause + OrderByClause OleDbDataAdapter adapter = new OleDbDataAdapter(SelectString, MyConn)

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• How do I debug random Timeout::Error: execution expired

  - by ChrisH

  We are using Rails 2.3.5 and have been experiencing seemingly random Timeout::Error: execution expired errors. The errors reported by Hoptoad are not consistently in any particular controller and show up everywhere from user sessions to account settings to some of our core functionality controllers. The vast majority of requests do not Timeout but there are enough to cause concern. Is this normal? If so, what are some things to look at to decrease the occurance? If not, has anyone run into this and what are some common problems that can trigger an error like this.

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• Testing complex entities

  - by Carlos

  I've got a C# form, with various controls on it. The form controls an ongoing process, and there are many, many aspects that need to be right for the program to run correctly. Each part can be unit tested (for instance, loading some coefficients, drawing some diagnostics) but I often run into problems that are best described with an example: "If I click here, then here, then change this, then re-open the form, then click here, it crashes or produces an error" I've tried my best to use common code organisational ideas (inheritance, DRY, separation of concerns) but there never seems to be a way to test every single path, and inevitably, a form with several controls will have a huge number of ways to execute. What can I read (preferably online) that addresses this kind of issue, and is there a (non-generic) term for it. This isn't a specific problem I'm having, but one that creeps up on me, especially with WinForms.

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• PHP anonymous functions scope question

  - by Dan

  Hi, I'm trying to sort an array of objects by a common property, however I cannot get my $property parameter to register in the inner function (I can use it in the outer one OK). The way I read the documentation, it sounded like the parameter would be available, have I misunderstood something? Here is what I have: public static function sortObjectsByProperty($objects, $property) { function compare_object($a, $b) { $a = $a->$property; $b = $b->$property; if ($a->$property == $b->$property) { return 0; } return ($a->$property > $b->$property) ? +1 : -1; } usort($objects, 'compare_object'); return $objects; } Any advice appreciated. Thanks.

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• Lazy loading in Hibernate

  - by Steve

  My Java Web application uses Hibernate to perform ORM. In some of my objects, I use lazy loading to avoid getting data until I absolutely need it. The problem is that I load the initial object in a session, and then that session is destroyed. When I later attempt to resolve the lazy-loaded collections in my object I get the following error: org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: common.model.impl.User.groups, no session or session was closed I tried associating a new session with the collection and then resolving, but this gives the same results. Does anyone know how I can resolve the lazy collections once the original session is gone? Thanks... --Steve

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• How to fetch message body and attachments in XML format using php/linux from Lotus Domino server?

  - by too

  Has anybody some information about accessing Lotus Domino server to fetch entire mail contents by http(s) requests from php linux server? The article by Andrei Kouvchinnikov describes well how to fetch message list in notes mail folders; after obtaining session id during login one can for example select top 100 messages by calling: https://your.server.domain/mail_db/mailbox.nsf/($Inbox)?ReadViewEntries&Start=1&Count=100 And this works perfectly. The problem arises when I am trying to get message contents (0A1DA5EEB7B65277C12576F50055D811 is an example message unique Id): https://your.server.domain/mail_db/mailbox.nsf/($Inbox)/0A1DA5EEB7B65277C12576F50055D811/?OpenDocument Such request in IE shows frameset with data hard to parse, in less common browsers like Opera it informs about unsupported browser. Ideally if it is possible to fetch notes message contents and all attachments by requesting it in the url, has anybody some information what request would it be? Link to Lotus web calls reference would be even more beneficial.

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• Comparing images using SIFT

  - by Luís Fernando

  I'm trying to compare 2 images that are taken from a digital camera. Since there may be movement on the camera, I want to first make the pictures "match" and then compare (using some distant function). To match them, I'm thinking about cropping the second picture and using SIFT to find it inside the first picture... it will probably have a small difference on scale/translation/rotation so then I'd need to find the transformation matrix that converts image 1 to image 2 (based on points found by SIFT) any ideas on how to do that (or I guess that's a common problem that may have some opensource implementation?)? thanks

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• Recursive vs. Iterative algorithms

  - by teehoo

  I'm implementing the Euclidian algorithm for finding the GCD (Greatest Common Divisor) of two integers. Two sample implementations are given: Recursive and Iterative. http://en.wikipedia.org/wiki/Euclidean_algorithm#Implementations My Question: In school I remember my professors talking about recursive functions like they were all the rage, but I have one doubt. Compared to an iterative version don't recursive algorithms take up more stack space and therefore much more memory? Also, because calling a function requires uses some overhead for initialization, aren't recursive algorithms more slower than their iterative counterpart?

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• make website page get news articles from feeds

  - by Andy

  Hi, I would like to start publishing some news articles from time to time. An option would be to create a new web page for every article but this sounds like it can be done easier. For instance I noticed clear channel uses some kind of feed, like: http://www.z100.com/cc-common/news/sections/newsarticle.html?feed=104650&article=7011404 I don't know what it means and how it works but looks like a nice way to get the article from some kind of database I guess? Does someone knows how this works, or some other way to create new articles etc, some dynamical functionality for instance to generate links to the articles and get the right article from a database for example. thanks!

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• Mono and Apache are serving files with no ASP.NET processing

  - by dnord

  On a new Rackspace Cloud Server box (Ubuntu 9.10), I've installed apache2, libapache2-mod-mono, and mod-mono-server2. I've disabled mod_mono and enabled mod_mono_auto, but whatever I do, requests for Default.aspx return the actual contents of Default.aspx (in this case, "This is a marker file generated by the precompilation tool, and should not be deleted!") I've installed XSP, and it looks like it works okay, but I'd like to use Apache with mod_mono (seems a more common configuration) if I can get it running. However, this is no error messages and no hints, with Google obviously not terribly helpful. What else can I look for to make sure I'm configured correctly? How can I test further?

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• What is your longest-held programming assumption that turned out to be incorrect?

  - by Demi

  I am doing some research into common errors and poor assumptions made by junior (and perhaps senior) software engineers. What was your longest-held poor assumption that was eventually corrected? For example: I at one point failed to understand that the size of an integer was not a standard (depends on the language and target). A bit embarrassing to state, but there it is. Be frank: what hard-held belief did you have, and roughly how long did you maintain the assumption? It can be about an algorithm, a language, a programming concept, testing, anything under the computer science domain.

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• Android Class which extends Dialog, how to clear TextViews before it is displayed

  - by wuntee

  I have a class that extends android.app.Dialog, the layout is done in an xml file, and the setup (button listeners, etc) is done on the onCreate method. My problem is that whenever the dialog is displayed, then dismissed, and displayed again, the Editable TextViews are still populated with the information that was displayed previously. What is the common way to clear these text fields? Remember - this is a separate class that extends Dialog - so there is no 'onDialogCreate' like Activity has. Or, perhaps I am extending the wrong class? There is just a lot of processing being done, and do not want to have all the code in the main Activity. I would like it to be in a separate Class. I tried to extend AlertDialog, but it does not create the border like Dialog does. Any help would be great. The dialog is shown via the Activity: protected Dialog onCreateDialog(int id) { switch(id){ case DIALOG_NEW_SAFE: return(new NewSafeDialog(this)); default: return(null); } }

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• How do I set my development web browser in VS2010?

  - by blesh

  I don't like to use IE for my system default web browser. but I do want to set IE as my browser in VS2010 because it works a little nicer for debugging and I like to develop to the lowest common denominator. (jab, lol)... anyhow, can I default to debugging against IE? I know in VS2008 you just had to "Browse With..." on an .aspx page. But that option doesn't exist in VS2010 RC. What gives?

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• Accurate Timings with Oscilloscopes on PC

  - by Paul Bullough

  In the world of embedded software (firmware) it is fairly common to observe the order of events, take timings and optimise a program by getting it to waggle PIO lines and capturing their behavior on an oscilloscope. In days gone by it was possible to toggle pins on the serial and parallel ports to achieve much the same thing on PC-based software. This made it possible to capture host PC-based software events and firmware events on the same trace and examine host software/firmware interactions. Now, my new laptop ... no serial or parallel ports! This is increasingly the case. So, does anyone have any suggestions as to go about emitting accurate timing signals off a "modern" PC? It strikes me that we don't have any immediately programmable, lag-free output pins left. The solution needs to run off a laptop, so using add-on cards that only plug into desktops are not permitted.

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• Can SVG render partially if gzipped and chunk-transferred?

  - by Scott Stafford

  Hi - I have some large, dynamically generated SVGs that are being served over a relatively slow internet connection. I'm trying to optimize them to be viewable as fast as possible. If I set the server to Content-Encoding: gzip and Transfer-Encoding: chunked, will any SVG viewers take advantage of that and render it partially, as it is transferred? If not, are there other ways to get it to render as-it-streams? I could break it up into several SVG pieces but that will be a lot of work, I was hoping for server settings... The most common users use IE7 with the Adobe SVG Viewer plugin. I doubt it matters but I'm serving with C#/ASP.NET and IIS6.

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