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  • Why does VS2005 skip execution of lines when debugging managed C++ without optimizations?

    - by Sakin
    I ran into a rather odd behavior that I don't even know how to start describing. I wrote a piece of managed C++ code that makes calls to native methods. A (very) simplified version of the code would look like this (I know it looks like a full native function, just assume there is managed stuff being done all over the place): int somefunction(ptrHolder x) { // the accessptr method returns a native pointer if (x.accessptr() != nullptr) // I tried this with nullptr, NULL, 0) { try { x->doSomeNativeVeryImportantStuff(); // or whatever, doesn't matter } catch (SomeCustomExceptionClass &) { return 0; } } SomeOtherNativeClass::doStaticMagic(); return 1; } I compiled this code without optimizations using the /clr flag (VS.NET 2005, SP2) and when running it in the debugger I get to the if statement, since the pointer is actually null, I don't enter the if, but surprisingly, the cursor jumps directly to the return 1 statement, ignoring the doStaticMagic() method completely!!! When looking at the assembly code, I see that it really jumps directly to that line. If I force the debugger to enter the if block, I also jump to the return 1 statement after I press F10. Any ideas why this is happening? Thanks, Ariel

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  • PHP: Extract direct sub directory from path string

    - by Nebs
    I need to extract the name of the direct sub directory from a full path string. For example, say we have: $str = "dir1/dir2/dir3/dir4/filename.ext"; $dir = "dir1/dir2"; Then the name of the sub-directory in the $str path relative to $dir would be "dir3". Note that $dir never has '/' at the ends. So the function should be: $subdir = getsubdir($str,$dir); echo $subdir; // Outputs "dir3" If $dir="dir1" then the output would be "dir2". If $dir="dir1/dir2/dir3/dir4" then the output would be "" (empty). If $dir="" then the output would be "dir1". Etc.. Currently this is what I have, and it works (as far as I've tested it). I'm just wondering if there's a simpler way since I find I'm using a lot of string functions. Maybe there's some magic regexp to do this in one line? (I'm not too good with regexp unfortunately). function getsubdir($str,$dir) { // Remove the filename $str = dirname($str); // Remove the $dir if(!empty($dir)){ $str = str_replace($dir,"",$str); } // Remove the leading '/' if there is one $si = stripos($str,"/"); if($si == 0){ $str = substr($str,1); } // Remove everything after the subdir (if there is anything) $lastpart = strchr($str,"/"); $str = str_replace($lastpart,"",$str); return $str; } As you can see, it's a little hacky in order to handle some odd cases (no '/' in input, empty input, etc). I hope all that made sense. Any help/suggestions are welcome.

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  • Efficient update of SQLite table with many records

    - by blackrim
    I am trying to use sqlite (sqlite3) for a project to store hundreds of thousands of records (would like sqlite so users of the program don't have to run a [my]sql server). I have to update hundreds of thousands of records sometimes to enter left right values (they are hierarchical), but have found the standard update table set left_value = 4, right_value = 5 where id = 12340; to be very slow. I have tried surrounding every thousand or so with begin; .... update... update table set left_value = 4, right_value = 5 where id = 12340; update... .... commit; but again, very slow. Odd, because when I populate it with a few hundred thousand (with inserts), it finishes in seconds. I am currently trying to test the speed in python (the slowness is at the command line and python) before I move it to the C++ implementation, but right now this is way to slow and I need to find a new solution unless I am doing something wrong. Thoughts? (would take open source alternative to SQLite that is portable as well)

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  • Is there anything on a local network or desktop environment that could effect JScript execution?

    - by uku
    I know this sounds odd. The JS on my project functions perfectly, except when the web site is accessed using computers at one specific company. To make things even more difficult, the JS fails only about 50% of the time when run from that company. The JS failure occurs with FireFox, Chrome, and IE. I have tested this myself using FF and Chrome on a thumb drive. The browsers on my thumb always display my project site perfectly, except when run from a computer on said company's network where they fail at the same rate as the installed browsers. My JS is using jQuery and making some Ajax calls. The Ajax calls are where the failure is occurring. To diagnose the problem I created a logging function for my Ajax calls and recorded success and failure. Over a one month period, there were only a handful of failures (about 1%) from all access points other than this company. Oddly enough, the Ajax calls in the logging function are not failing. There is nothing exotic there - Just Win XP SP3. I have never noticed any other unusual behavior from their network. The company is a division of a mega ISP and is on their corporate network. Any other suggestions for troubleshooting would be welcome.

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  • Cached data accessed by reference?

    - by arthurdent510
    I am running into an odd problem, and this is the only thing I can think of. I'm storing a list in cache, and I am randomly losing items from my list as users use the site. I have a class that is called that either goes to cache and returns the list from there, or if the cache is over a certain time frame old, it goes to the database and refreshes the cache. So when I pull the data from cache, this is what it looks like.... results = (List<Software>)cache["software"]; And then I return results and do some processing, filter for security, and eventually it winds up on the screen. For each Software record, there can be multiple resources attached to it, and based on how the security goes they may see some, all, or none of the records. So in the security check it will remove some of those resources from the software record. So my question is.... when I return my results list, is it a reference directly to the cache object? So when I remove a resource from the software object, it is really removing from cache as well? If that is the case, is there any way to not return it as a reference? Thanks!

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  • naming a function that exhibits "set if not equal" behavior

    - by Chris Sears
    This might be an odd question, but I'm looking for a word to use in a function name. I'm normally good at coming up with succinct, meaningful function names, but this one has me stumped so I thought I'd appeal for help. The function will take some desired state as an argument and compare it to the current state. If no change is needed, the function will exit normally without doing anything. Otherwise, the function will take some action to achieve the desired state. For example, if wanted to make sure the front door was closed, i might say: my_house.<something>_front_door('closed') What word or term should use in place of the something? I'd like it to be short, readable, and minimize the astonishment factor. A couple clarifying points... I would want someone calling the function to intuitively know they didn't need to wrap the function an 'if' that checks the current state. For example, this would be bad: if my_house.front_door_is_open(): my_house.<something>_front_door('closed') Also, they should know that the function won't throw an exception if the desired state matches the current state. So this should never happen: try: my_house.<something>_front_door('closed') except DoorWasAlreadyClosedException: pass Here are some options I've considered: my_house.set_front_door('closed') my_house.setne_front_door('closed') # ne=not equal, from the setne x86 instruction my_house.ensure_front_door('closed') my_house.configure_front_door('closed') my_house.update_front_door('closed') my_house.make_front_door('closed') my_house.remediate_front_door('closed') And I'm open to other forms, but most I've thought of don't improve readability. Such as... my_house.ensure_front_door_is('closed') my_house.conditionally_update_front_door('closed') my_house.change_front_door_if_needed('closed') Thanks for any input!

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  • exit /B 0 does not work...

    - by murxx
    Hi, I have the following problem: I have created a batch script which calls itself in there (for being able to write a log in parallel). In the script I start another process (like start startServer.bat) which starts up a java process and keeps opened up all the time. In my original script I wait 30 seconds, check if the process is running and do an: exit /B 0 Unfortunately that does not work, the window shows that the exit /B 0 is being evaluated, but the window still keeps open. When I close the window with the other process (meaning the "child" processes started up in my .bat) my script continues its run. So: scriptA.bat - in there I call: start startServer.bat - wait 30 seconds - check is server is started - exit /B 0 Process hangs up! What's very odd, if I wrap another script around, like: scriptB.bat - call scriptA.bat ----- in there I call: start startServer.bat ----- wait 30 seconds ----- check is server is started ----- exit /B 0 - scriptA.bat continues without any hangup! I also tried the same with exit 0 (without /B) also, same result! In the first case it hangs up, in the second case my window closes as expected... Has anyone of you ever had such a problem before and knows what's wrong here? Process hangs up!

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  • What is this: main:for(...){...} doing?

    - by David Murdoch
    I pulled up the NWmatcher source code for some light morning reading and noticed this odd bit of code I'd never seen in javascript before: main:for(/*irrelevant loop stuff*/){/*...*/} This snippet can be found in the compileGroup method on line 441 (nwmatcher-1.1.1) return new Function('c,s,d,h', 'var k,e,r,n,C,N,T,X=0,x=0;main:for(k=0,r=[];e=N=c[k];k++){' + SKIP_COMMENTS + source + '}return r;' ); Now I figured out what main: is doing on my own. If you have a loop within a loop and want to skip to the next iteration of the outer loop (without completing the inner OR the outer loop) you can execute continue main. Example: // This is obviously not the optimal way to find primes... function getPrimes(max) { var primes = [2], //seed sqrt = Math.sqrt, i = 3, j, s; outer: for (; i <= max; s = sqrt(i += 2)) { j = 3; while (j <= s) { if (i % j === 0) { // if we get here j += 2 and primes.push(i) are // not executed for the current iteration of i continue outer; } j += 2; } primes.push(i); } return primes; } What is this called? Are there any browsers that don't support it? Are there other uses for it other than continue?

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  • power and modulo on the fly for big numbers

    - by user unknown
    I raise some basis b to the power p and take the modulo m of that. Let's assume b=55170 or 55172 and m=3043839241 (which happens to be the square of 55171). The linux-calculator bc gives the results (we need this for control): echo "p=5606;b=55171;m=b*b;((b-1)^p)%m;((b+1)^p)%m" | bc 2734550616 309288627 Now calculating 55170^5606 gives a somewhat large number, but since I have to do a modulooperation, I can circumvent the usage of BigInt, I thought, because of: (a*b) % c == ((a%c) * (b%c))%c i.e. (9*7) % 5 == ((9%5) * (7%5))%5 => 63 % 5 == (4 * 2) %5 => 3 == 8 % 5 ... and a^d = a^(b+c) = a^b * a^c, therefore I can divide b+c by 2, which gives, for even or odd ds d/2 and d-(d/2), so for 8^5 I can calculate 8^2 * 8^3. So my (defective) method, which always cut's off the divisor on the fly looks like that: def powMod (b: Long, pot: Int, mod: Long) : Long = { if (pot == 1) b % mod else { val pot2 = pot/2 val pm1 = powMod (b, pot, mod) val pm2 = powMod (b, pot-pot2, mod) (pm1 * pm2) % mod } } and feeded with some values, powMod (55170, 5606, 3043839241L) res2: Long = 1885539617 powMod (55172, 5606, 3043839241L) res4: Long = 309288627 As we can see, the second result is exactly the same as the one above, but the first one looks quiet different. I'm doing a lot of such calculations, and they seem to be accurate as long as they stay in the range of Int, but I can't see any error. Using a BigInt works as well, but is way too slow: def calc2 (n: Int, pri: Long) = { val p: BigInt = pri val p3 = p * p val p1 = (p-1).pow (n) % (p3) val p2 = (p+1).pow (n) % (p3) print ("p1: " + p1 + " p2: " + p2) } calc2 (5606, 55171) p1: 2734550616 p2: 309288627 (same result as with bc) Can somebody see the error in powMod?

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  • Can I split a single SQL 2008 DB Table into multiple filegroups, based on a discriminator column?

    - by Pure.Krome
    Hi folks, I've got a SQL Server 2008 R2 database which has a number of tables. Two of these tables contains a lot of large data .. mainly because one of them is VARBINARY(MAX) and the sister table is GEOGRAPHY. (Why two tables? Read Below if you're interested***) The data in these tables are geospatial shapes, such as zipcode boundaries. Now, the first 70K odd rows are for DataType = 1 the rest 5mil rows are for DataType = 2 Now, is it possible to split the table data into two files? so all rows that are for DataType != 2 goes into File_A and DataType = 2 goes into File_B? This way, when I backup the DB, I can skip adding File_B so my download is waaaaay smaller? Is this possible? I guessing you might be thinking - why not keep them as TWO extra tables? Mainly because in the code, the data is conceptually the same .. it's just happens that I want to split the storage of this model data. It really messes up my model if I now how two aggregates in my model, instead of one. ***Entity Framework doesn't like Tables with GEOGRAPHY, so i have to create a new table which transforms the GEOGRAPHY to VARBINARY, and then drop that into EF.

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  • When to define SDD operations System->Actor?

    - by devoured elysium
    I am having some trouble understanding how to make SDDs, as I don't fully grasp why in some cases one should define operations for System - Actor and in others don't. Here is an example: 1) The User tells the System that wants to buy some tickets, stating his client number. 2) The System confirms that the given client number is valid. 3) The User tells the System the movie that wants to see. 4) The System shows the set of available sessions and seats for that movie. 5) The System asks the user which session/seat he wants. 6) The user tells the System the chosen session/seat. This would be converted to: a) -----> tellClientNumber(clientNumber) b) <----- validClientNumber c) -----> tellMovieToSee(movie) d) <----- showsAvailableSeatsHours e) -----> tellSystemChosenSessionSeat(session, seat) I know that when we are dealing with SDD's we are still far away from coding. But I can't help trying to imagine how it how it would have been had I to convert it right away to code: I can understand 1) and 2). It's like if it was a C#/Java method with the following signature: boolean tellClientNumber(clientNumber) so I put both on the SDD. Then, we have the pair 3) 4). I can imagine that as something as: SomeDataStructureThatHoldsAvailableSessionsSeats tellSystemMovieToSee(movie) Now, the problem: From what I've come to understand, my lecturer says that we shouldn't make an operation on the SDD for 5) as we should only show operations from the Actor to the System and when the System is either presenting us data (as in c)) or validating sent data (such as in b)). I find this odd, as if I try to imagine this like a DOS app where you have to put your input sequencially, it makes sense to make an arrow even for 5). Why is this wrong? How should I try to visualize this? Thanks

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  • Recreating a workflow instance with the same instance id

    - by Miron Brezuleanu
    We have some objects that have an associated workflow instance. The objects are identified with a GUID, which is also the GUID of the workflow instance associated with the object. We need to restart (see NOTE 3 for the meaning of 'restart') the workflow instance if the workflow definition changed (there is no state in the workflow itself and it is written to support restarting in this manner). The restarting is performed by calling Terminate on the WorkflowInstance, then recreating the instance with the same GUID. The weird part is that this works every other attempt (odd attempts - the workflow is stopped, but for some reason doesn't restart, even attempt - the already terminated workflow is recreated and started successfully). While I admit that using 'second hand' GUIDs is a sign of extraordinary cheapness (and something we plan to change), I'm wondering why this isn't working. Any ideas? NOTES: The terminated workflow instance is passivated (waiting for a notification) at the time of the termination. The Terminate call successfully deletes the data persisted in the database for that instance. We're using 'restarting' with a meaning that's less common in the context of WF - not restarting a passivated instance, but force the workflow to start again from the beginning of its definition. Thanks!

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  • When do Symfony's user attributes get written to session?

    - by Rob Wilkerson
    I have a Symfony app that populates the "widgets" of a portal application and I'm noticing something (that seems) odd. The portal app has iframes that make calls to the Symfony app. On each of those calls, a random user key is passed on the query string. The Symfony app stores that key its session using myUser->setAttribute(). If the incoming value is different from what it has in session, it overwrites the session value. In pseudo-code (and applying a synchronous nature for clarity even though it may not exist): # Widget request arrives with ?foo=bar if the user attribute 'foo' does not equal 'bar' overwrite the user attribute 'foo' with 'bar' end What I'm noticing is that, on a portal page with multiple widgets (read: multiple requests coming in more or less simultaneously) where the value needs to be overwritten, each request is trying to overwrite. Is this a timing problem? When I look at the log prints, I'd expect the first request that arrives to overwrite and subsequent requests to see that the user attribute they received matches what was just put into cache by the initial request. In this scenario, it could be that subsequent requests begin (and are checked) even before the first one--the one that should overwrite the cached value--has completely finished. Are session values not really available to subsequent requests until one request has completed entirely or could there be something else that I'm missing? Thanks.

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  • At what point is it worth using a database?

    - by radix07
    I have a question relating to databases and at what point is worth diving into one. I am primarily an embedded engineer, but I am writing an application using QT to interface with our controller. We are at an odd point where we have enough data that it would be feasible to implement a database (around 700+ items and growing) to manage everything, but I am not sure it is worth the time right now to deal with. I have no problems implementing the GUI with files generated from excel and parsed in, but it gets tedious and hard to track even with VBA scripts. I have been playing around with converting our data into something more manageable for the application side with Microsoft Access and that seems to be working well. If that works out I am only a step (or several) away from using an SQL database and using the QT library to access and modify it. I don't have much experience managing data at this level and am curious what may be the best way to approach this. So what are some of the real benefits of using a database if any in this case? I realize much of this can be very application specific, but some general ideas and suggestions on how to straddle the embedded/application programming line would be helpful. Thanks

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  • "end()" iterator for back inserters?

    - by Thanatos
    For iterators such as those returned from std::back_inserter(), is there something that can be used as an "end" iterator? This seems a little nonsensical at first, but I have an API which is: template<typename InputIterator, typename OutputIterator> void foo( InputIterator input_begin, InputIterator input_end, OutputIterator output_begin, OutputIterator output_end ); foo performs some operation on the input sequence, generating an output sequence. (Who's length is known to foo but may or may not be equal to the input sequence's length.) The taking of the output_end parameter is the odd part: std::copy doesn't do this, for example, and assumes you're not going to pass it garbage. foo does it to provide range checking: if you pass a range too small, it throws an exception, in the name of defensive programming. (Instead of potentially overwriting random bits in memory.) Now, say I want to pass foo a back inserter, specifically one from a std::vector which has no limit outside of memory constraints. I still need a "end" iterator - in this case, something that will never compare equal. (Or, if I had a std::vector but with a restriction on length, perhaps it might sometimes compare equal?) How do I go about doing this? I do have the ability to change foo's API - is it better to not check the range, and instead provide an alternate means to get the required output range? (Which would be needed anyways for raw arrays, but not required for back inserters into a vector.) This would seem less robust, but I'm struggling to make the "robust" (above) work.

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  • Using "margin: 0 auto;" in Internet Explorer 8

    - by stusmith
    I'm in the process of doing some advance IE8 testing, and it seems that the old technique of using "margin: 0 auto;" doesn't work in all cases in IE8. The following piece of HTML gives a centered button in FF3, Opera, Safari, Chrome, IE7, and IE8 compat, but NOT in IE8 standard: <div style="height: 500px; width: 500px; background-color: Yellow;"> <input type="submit" style="display: block; margin: 0 auto;" /> </div> (As a work-around I can add an explicit width to the button). So the question is: which browsers are correct? Or is this one of those cases where the behaviour is undefined? (My thinking is that all the browsers are incorrect - shouldn't the button be 100% width if it's "display: block"?) UPDATE: I'm being a dunce. Since input isn't a block-level element, I should have just contained it within a div with "text-align: center". Having said that, for curiosity's sake, I'd still like to know whether the button should or shouldn't be centered in the example above. FOR THE BOUNTY: I know I'm doing odd things in the example, and as I point out in the update, I should have just aligned it center. For the bounty, I'd like references to the specs that answer: If I set "display: block", should the button be width 100%? Or is this undefined? Since the display is block, should "margin: 0 auto;" center the button, or not, or undefined?

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  • gems, bundle command, and ruby not found in new terminal window

    - by user3579987
    So I installed ruby with rvm, ran a bundle install and installed a bunch of gems, etc. It all works just fine in the original terminal window I did all of this in but I opened up a new terminal window and now I'm getting errors like bundle: command not found and gem command not found. I tried doing a symbolic link for the gem command but then when I do gem list it displays a much shorter list of my local gems and not at all the ones I need for bundle install. Is there something I need to do to configure bash or rvm so that it recognizes that I did indeed install all the gems I have installed? name@crunchbang:~/ug_research_portal$ which gem /home/name/.rvm/rubies/ruby-2.1.1/bin/gem name@crunchbang:~/ug_research_portal$ which ruby /home/name/.rvm/rubies/ruby-2.1.1/bin/ruby And in ~/.bashrc: GEM_HOME="/home/name/.rvm/gems/ruby-2.1.1" GEMGLOBAL_HOME="/home/ name/.rvm/gems/ruby-2.1.1@global" export PATH=$PATH:$GEM_HOME/bin:$GEMGLOBAL_HOME/bin:$HOME/.rvm/bin Edit: Looks like my $PATH is somehow wrong? bash: /home/name/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games:/home/name/.rvm/gems/ruby-2.1.1/bin:/home/name/.rvm/gems/ruby-2.1.1@global/bin:/home/name/.rvm/bin/: No such file or directory which is odd since ls for /home/name/.rvm/bin and /home/name/.rvm/gems/ruby-2.1.1@global/bin and /home/name/.rvm/gems/ruby-2.1.1/bin work just fine Psych, I was just doing $PATH instead of echo "$PATH" which was giving me the No such file or directory error. The original problem still stands though.

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  • CSS Zebra Stripe a Specific Table tr:nth-child(even)

    - by BillR
    I want to zebra stripe only select tables using. I do not want to use jQuery for this. tbody tr:nth-child(even) td, tbody tr.even td {background:#e5ecf9;} When I put that in a css file it affects all tables on all pages that call the same stylesheet. What I would like to do is selectively apply it to specific tables. I have tried this, but it doesn't work. // in stylesheet .zebra_stripe{ tbody tr:nth-child(even) td, tbody tr.even td {background:#e5ecf9;} } // in html <table class="zebra_even"> <colgroup> <col class="width_10em" /> <col class="width_15em" /> </colgroup> <tr> <td>Odd row nice and clear.</td> <td>Some Stuff</td> </tr> <tr> <td>Even row nice and clear but it should be shaded.</td> <td>Some Stuff</td> </tr> </table> And this: <table> <colgroup> <col class="width_10em" /> <col class="width_15em" /> </colgroup> <tbody class="zebra_even"> The stylesheet works as it is properly formatting other elements of the html. Can someone help me with an answer to this problem? Thanks.

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  • Use CSS3 nth-child to alternate the float of images within DIV tags...

    - by Aaron Rodgers
    Basically, what I'm trying to create is a page of div tags, each has an image inside them and I'm trying to use CSS3's nth-child to alternate the float of that specific image. But for the life of me, I can't get the nth-child to locate those images. Here is my code so far... CSS .featureBlock img:nth-of-type(even) { float: left; } .featureBlock img:nth-of-type(odd) { float: right; } This is the HTML of one of those div tags.... <div class="featureBlock"> <h1>Multisize Players</h1> <div class="featureHelpBlock"><a href="#">More help with this</a></div> <img src="http://office2.vzaar.com/images/features/ft_multisize_players.png"> <span class="featureContent"><p>A variety of player sizes is important as we recognise the fact that no two videos or websites are ever the same and you will want something that suits your site&#8217;s look. So if you record your video in 4x3 (not widescreen) or 16x9 (widescreen) we have the range of player sizes to suit your exact needs.</p> <p>We encode the video at the time of uploading in the size that you choose so that the picture and sound quality is retained throughout. Users can choose from the following sizes:</p></span> <br style="clear:both"> </div> Hope this makes sense...

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  • When to define SDD(System Sequence Diagram) operations System->Actor?

    - by devoured elysium
    I am having some trouble understanding how to make System Sequence Diagrams, as I don't fully grasp why in some cases one should define operations for System - Actor and in others don't. Here is an example: Let's assume the System is a Cinema Ticket Store and the Actor is a client that wants to buy a ticket. 1) The User tells the System that wants to buy some tickets, stating his client number. 2) The System confirms that the given client number is valid. 3) The User tells the System the movie that wants to see. 4) The System shows the set of available sessions and seats for that movie. 5) The System asks the user which session/seat he wants. 6) The User tells the System the chosen session/seat. This would be converted to: a) -----> tellClientNumber(clientNumber) b) <----- validClientNumber c) -----> tellMovieToSee(movie) d) <----- showsAvailableSeatsHours e) -----> tellSystemChosenSessionSeat(session, seat) I know that when we are dealing with SDD's we are still far away from coding. But I can't help trying to imagine how it how it would have been had I to convert it right away to code: I can understand 1) and 2). It's like if it was a C#/Java method with the following signature: boolean tellClientNumber(clientNumber) so I put both on the SDD. Then, we have the pair 3) 4). I can imagine that as something as: SomeDataStructureThatHoldsAvailableSessionsSeats tellSystemMovieToSee(movie) Now, the problem: From what I've come to understand, my lecturer says that we shouldn't make an operation on the SDD for 5) as we should only show operations from the Actor to the System and when the System is either presenting us data (as in c)) or validating sent data (such as in b)). I find this odd, as if I try to imagine this like a DOS app where you have to put your input sequencially, it makes sense to make an arrow even for 5). Why is this wrong? How should I try to visualize this? Thanks

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  • Why is T() = T() allowed?

    - by Rimo
    I believe the expression T() creates an rvalue (by the Standard). However, the following code compiles (at least on gcc4.0): class T {}; int main() { T() = T(); } I know technically this is possible because member functions can be invoked on temporaries and the above is just invoking the operator= on the rvalue temporary created from the first T(). But conceptually this is like assigning a new value to an rvalue. Is there a good reason why this is allowed? Edit: The reason I find this odd is it's strictly forbidden on built-in types yet allowed on user-defined types. For example, int(2) = int(3) won't compile because that is an "invalid lvalue in assignment". So I guess the real question is, was this somewhat inconsistent behavior built into the language for a reason? Or is it there for some historical reason? (E.g it would be conceptually more sound to allow only const member functions to be invoked on rvalue expressions, but that cannot be done because that might break some existing code.)

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  • Django Admin Running Same Query Thousands of Times for Model

    - by Tom
    Running into an odd . . . loop when trying to view a model in the Django admin. I have three related models (code trimmed for brevity, hopefully I didn't trim something I shouldn't have): class Association(models.Model): somecompany_entity_id = models.CharField(max_length=10, db_index=True) name = models.CharField(max_length=200) def __unicode__(self): return self.name class ResidentialUnit(models.Model): building = models.CharField(max_length=10) app_number = models.CharField(max_length=10) unit_number = models.CharField(max_length=10) unit_description = models.CharField(max_length=100, blank=True) association = models.ForeignKey(Association) created = models.DateTimeField(auto_now_add=True) updated = models.DateTimeField(auto_now=True) def __unicode__(self): return '%s: %s, Unit %s' % (self.association, self.building, self.unit_number) class Resident(models.Model): unit = models.ForeignKey(ResidentialUnit) type = models.CharField(max_length=20, blank=True, default='') lookup_key = models.CharField(max_length=200) jenark_id = models.CharField(max_length=20, blank=True) user = models.ForeignKey(User) is_association_admin = models.BooleanField(default=False, db_index=True) show_in_contact_list = models.BooleanField(default=False, db_index=True) created = models.DateTimeField(auto_now_add=True) updated = models.DateTimeField(auto_now=True) _phones = {} home_phone = None work_phone = None cell_phone = None app_number = None account_cache_key = None def __unicode__(self): return '%s' % self.user.get_full_name() It's the last model that's causing the problem. Trying to look at a Resident in the admin takes 10-20 seconds. If I take 'self.association' out of the __unicode__ method for ResidentialUnit, a resident page renders pretty quickly. Looking at it in the debug toolbar, without the association name in ResidentialUnit (which is a foreign key on Resident), the page runs 14 queries. With the association name put back in, it runs a far more impressive 4,872 queries. The strangest part is the extra queries all seem to be looking up the association name. They all come from the same line, the __unicode__ method for ResidentialUnit. Each one is the exact same thing, e.g., SELECT `residents_association`.`id`, `residents_association`.`jenark_entity_id`, `residents_association`.`name` FROM `residents_association` WHERE `residents_association`.`id` = 1096 ORDER BY `residents_association`.`name` ASC I assume I've managed to create a circular reference, but if it were truly circular, it would just die, not run 4000x and then return. Having trouble finding a good Google or StackOverflow result for this.

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  • Why can't multiple programmatically generated FilteringSelect's share a single store?

    - by yarmiganosca
    Before you ask, a MultiSelect wouldn't really be intuitive for the user in this instance. I have an object, with an array as its value for 'items', that's provided on the page in a var statement. I also have a function that generates and places dijit.form.FilteringSelects and is triggered on a certain button's click event. Every one of these selects should have the aformentioned object as their 'store' attribute. If I write store: new dojo.data.ItemFileReadStore({ data: object_name }), in my select initialization code, I get weird behavior: I click the generate button 2 times and get 2 FilteringSelects (call them A,B). I click on B's dropdown piece, and the menu appears attached to B. Then I click on A's dropdown button, and menu appears attached to A. If I then go back and click on B's dropdown button again, nothing happens (well not nothing; an error gets thrown). However, if instead, I have data: {items: array_literal} everything works fine, and I switch back and forth between the 2 as much as I want. As the data: statement appears once in the javascript code, this isn't a big deal (now that I have a workaround at least). It is however, exceedingly odd. I attempted to dig into the source code, to no avail.Anybody have any idea what's going on here?

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  • Large free block of english non-pronoun text

    - by Tom
    As part of teaching myself python I've written a script which allows a user to play hangman. At the moment, the hangman word to be guessed is simply entered manually at the start of the script's code. I want instead for the script to choose randomly from a large list of english words. This I know how to do - my problem is finding that list of words to work from in the first place. Does anyone know of a source on the net for, say, 1000 common english words where they can be downloaded as a block of text or something similar that I can work with? (My initial thought was grabbing a chunk of a novel from project gutenburg [this project is only for my own amusement and won't be available anywhere else so copyright etc doesn't matter hugely to me btw], but anything like that is likely to contain too many names or non-standard words that wouldn't be suitable for hangman. I need text that only has words legal for use in scrabble, basically). It's a slightly odd question for here I suppose, but actually I thought the answer might be of use not just to me but anyone else working on a project for a wordgame or similar that needs a large seed list of words to work from. Many thanks for any links or suggestions :)

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  • Calculations on the iteration count in for loop in Ruby 1.8.7

    - by user1805035
    I was playing around with Ruby and Latex to create a color coding set. I'm more than a novice with C++, but haven't looked at Ruby until now. So, still learning a lot of coding. I have the following block of code below. When attempting to run this, band1 = 1e+02. I've tried band1 = (BigDecimal(i) * 100).to_f thinking maybe there was some odd floating point issue. This is just me trying anything though as an integer multiplied by an integer should create an integer, if I'm still thinking correctly. I've tried a variety of other things as well (things that I can do in C++, but this ain't C++), but to no avail. (1..9).each do |i| #Band 1 (0..9).each do |j| #Band 2 (0..11).each do |k| #Band 3 #Band 3 Start #these are the colors of the resistor bands b1 = $c_band12[i] b2 = $c_band12[j] b3 = $c_band3[k] b4 = "Gold" oms = ((i*100) + (j*10)) * $mult[k] band1 = i*100 band2 = j band3 = $mult[k] end end end Not sure what I'm missing. Should I be using .each_with_index through these iterations? I've tried this: (1..9).each_with_index {|i, indexi| #Band 1 (0..9).each_with_index {|j, indexj| #Band 2 (0..11).each_with_index {|k, indexk| #Band 3 #Band 3 Start #these are the colors of the resistor bands b1 = $c_band12[i] b2 = $c_band12[j] b3 = $c_band3[k] b4 = "Gold" oms = ((i*100) + (j*10)) * $mult[k] band1 = indexk * 100 and I get the same answer. I can't see why 1*100 should equate to such a large number? Thank you, AT

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