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• What should a hobbyist do to develop good programming skills after basics?

  - by thyrgle

  So I'll say right here that I'm no professional coder. I'm a hobbyist. And pretty much like other people I feel like I'm doing it wrong. Like this question A feeling that I'm not a good programmer if have began to feel like that. Now I know basically that they say you shouldn't worry and that your good even if you continuously doubt yourself. But, they are talking to him. I'm not like him (in the sense I'm more of a newbie)... I've been coding as a hobbyist for 3 years (3 hobbyist years mind you!) unlike his 10-11 years that he states. Also, the only thing I've probably read in-depth is Teach Yourself C++ in 21 Days. And before I continue, just so your not confused about the various questions I've posted on (mostly) iPhone and OpenGL, I have poked and prodded at those two things for a few months each and finally sort of got a hang of both of them. But, from what I've noticed, is that I suck at making good code. For me its not even a debate of whether I'm doing it wrong or not: I can tell (from the various spaghetti code I create and other various discrepancies I, and others, can see and have noted in my code). What is a good way to get rid of these awful habits of mine and do it in a more correct, or if there is no "correct way" then I mean "typical", way?

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• Draggable cards (touch enumeration) issue

  - by glitch

  I'm trying to let a player tap, drag and release a card from a fanned stack on the screen to a 4x4 field on the board. My cards are instantiated from a custom class that inherits from the UIImageView class. I started with the Touches sample app, and I modified the event handlers for touches to iterate over my player's card hand instead of the 3 squares the sample app allows you to move on screen. Everything works, until that is, I move the card I'm dragging near another card. I'm really drawing a blank here for the logic to get the cards to behave properly. Here's my code: - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { NSUInteger numTaps = [[touches anyObject] tapCount]; if(numTaps = 1) { for (UITouch *touch in touches) { [self dispatchFirstTouchAtPoint:[touch locationInView: self.boardCardView] forEvent:nil]; } } } -(void) dispatchFirstTouchAtPoint:(CGPoint)touchPoint forEvent:(UIEvent *)event { for (int i = 0; i<5; i++) { UIImageView *touchedCard = boardBuffer[i]; if (CGRectContainsPoint([touchedCard frame], touchPoint)) { [self animateFirstTouchAtPoint:touchPoint forView:touchedCard]; } } } - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { NSUInteger touchCount = 0; for (UITouch *touch in touches){ [self dispatchTouchEvent:[touch view] toPosition:[touch locationInView:self.boardCardView]]; touchCount++; } } My questions are: How do I get the touch logic to disallow other cards from being picked up by a dragging finger? Is there anyway I can only enumerate the objects that are directly below a player's finger and explicitly disable other objects from responding? Thanks!

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• C++ std::vector memory/allocation

  - by aaa

  from a previous question about vector capacity, http://stackoverflow.com/questions/2663170/stdvector-capacity-after-copying, Mr. Bailey said: In current C++ you are guaranteed that no reallocation occurs after a call to reserve until an insertion would take the size beyond the value of the previous call to reserve. Before a call to reserve, or after a call to reserve when the size is between the value of the previous call to reserve and the capacity the implementation is allowed to reallocate early if it so chooses. So, if I understand correctly, in order to assure that no relocation happens until capacity is exceeded, I must do reserve twice? can you please clarify it? I am using vector as a memory stack like this: std::vector<double> memory; memory.reserve(size); memory.insert(memory.end(), matrix.data().begin(), matrix.data().end()); // smaller than size size_t offset = memory.size(); memory.resize(memory.capacity(), 0); I need to guarantee that relocation does not happen in the above. thank you. ps: I would also like to know if there is a better way to manage memory stack in similar manner other than vector

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• create CLLocationCoordinate2D from array

  - by shani

  I have a plist with dictionary of array's with coordinates (stored as strings). I want to create a CLLocationCoordinate2D from every array and crate an overlay for the map. I did that - NSString *thePath = [[NSBundle mainBundle] pathForResource:@"Roots" ofType:@"plist"]; NSDictionary *pointsDic = [[NSDictionary alloc] initWithContentsOfFile:thePath]; NSArray *pointsArray = [NSArray arrayWithArray:[pointsDic objectForKey:@"roade1"]]; CLLocationCoordinate2D pointsToUse[256]; for(int i = 0; i < 256; i++) { CGPoint p = CGPointFromString([pointsArray objectAtIndex:i]); pointsToUse[i] = CLLocationCoordinate2DMake(p.x,p.y); NSLog(@"coord %f",pointsToUse [i].longitude); NSLog(@"coord %f",pointsToUse [i].latitude); } MKPolyline *myPolyline = [MKPolyline polylineWithCoordinates:pointsToUse count:256]; [[self mv] addOverlay:myPolyline]; but the app is crashing without any error. (BTW when i remove the addOverLay method the app does not crash). I have 2 questions- What am i doing wrong? I have tried to set the pointsArray count as the argument for the CLLocationCoordinate2D like that - CLLocationCoordinate2D pointsToUse[pointsArray count]; And i am getting an error. How can i set the CLLocationCoordinate2D dynamically ? Thanks for any help. Shani

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• find and replace values in csv using PHP

  - by peirix

  I'd think there was a question on this already, but I can't find one. Maybe the solution is too easy... Anyway, I have a csv and want to let the user change the values based on a name. I've already sorted out creating new name+value-pairs using the fopen('a') mode, using jQuery to send the AJAX call with newValue and newName. But say the content looks like this: host|http:www.stackoverflow.com folder|/questions/ folder2|/users/ And now I want to change the folder value. So I'll send in folder as oldName and /tags/ as newValue. What's the best way to overwrite the value? The order in the list doesn't matter, and the name will always be on the left, followed by a |(pipe), the value and then a new-line. My first thought was to read the list, store it in an array, search all the [0]'s for oldName, then change the [1] that belongs to it, and then write it back to a file. But I feel there is a better way around this? Any ideas? Maybe regex?

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• How to strongly type properties in JavaScript that map to models in C# ?

  - by Roberto Sebestyen

  I'm not even sure if I worded the question right, but I'll try and explain as clearly as possible with an example: In the following example scenario: 1) Take a class such as this: public class foo { public string firstName {get;set;} public string lastName {get;set} } 2) Serialize that into JSON, pass it over the wire to the Browser. 3) Browser de-serializes this and turns the JSON into a JavaScript object so that you can then access the properties like this: var foo = deSerialize("*******the JSON from above**************"); alert(foo.firstName); alert(foo.lastName); What if now a new developer comes along working on this project decides that firstName is no longer a suitable property name. Lets say they use ReSharper to rename this property, since ReSharper does a pretty good job at finding (almost) all the references to the property and renaming them appropriately. However ReSharper will not be able to rename the references within the JavaScript code (#3) since it has no way of knowing that these also really mean the same thing. Which means the programmer is left with the responsibility of manually finding these references and renaming those too. The risk is that if this is forgotten, no one will know about this error until someone tests that part of the code, or worse, slip through to the customer. Back to the actual question: I have been trying to think of a solution to this to some how strongly type these property names when used in javascript, so that a tool like ReSharper can successfully rename ALL usages of the property? Here is what I have been thinking for example (This would obviously not work unless i make some kind of static properties) var foo = deSerialize("*******the JSON from above**************"); alert(foo.<%=foo.firstName.GetPropertyName()%>) alert(foo.<%=foo.lastName.GetPropertyName()%>) But that is obviously not practical. Does anyone have any thoughts on this? Thanks, and kudos to all of the talented people answering questions on this site.

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• License of popular dictionary word lists (e.g. SOWPODS, TWL)? Copyright? Trademarks?

  - by BobbyJim

  (I'm not sure if this off-topic. I found a lot of voted-up questions about software licenses and this is related. Plus, I'm sure many of us have had the situation that we need to use a dictionary in our code) I'm making a (maybe commercial) word game and need to use a good word dictionary for checking words. The most common dictionaries to use are the SOWPODS or TWL lists that are used Scrabble tournaments; see here: http://www.scrabblist.com/ (I have nothing to do with this site by the way). I've seen loads of websites offering these two dictionaries for download and loads of word games advertise that they use them. However, I cannot find any licensing terms attached to these dictionaries wherever I download them. For the players of my game, I'd want to say what dictionary I'm using (e.g. "this game uses SOWPODS"). However, I'm nervous about what I can do legally. Does anyone know about if you can copyright lists of words? Does anyone know the licenses of TWL and SOWPODS? TWL and SOWPODS don't seem to have trademarks on them but I'd like to know for sure. I cannot find any good sources for this information. EDIT: Great, now the top result for "SOWPODS license" is my stackoverflow question. :)

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• Rails 3 MySQL 2 reports an error in what looks to be valid SQL syntax

  - by John Judd

  I am trying to use the following bit of code to help in seeding my database. I need to add data continually over development and do not want to have to completely reseed data every time I add something new to the seeds.rb file. So I added the following function to insert the data if it doesn't already exist. def AddSetting(group, name, value, desc) Admin::Setting.create({group: group, name: name, value: value, description: desc}) unless Admin::Setting.find_by_sql("SELECT * FROM admin_settings WHERE group = '#{group}' AND name = '#{name}';").exists? end AddSetting('google', 'analytics_id', '', 'The ID of your Google Analytics account.') AddSetting('general', 'page_title', '', '') AddSetting('general', 'tag_line', '', '') This function is included in the db/seeds.rb file. Is this the right way to do this? However I am getting the following error when I try to run it through rake. rake aborted! Mysql2::Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'group = 'google' AND name = 'analytics_id'' at line 1: SELECT * FROM admin_settings WHERE group = 'google' AND name = 'analytics_id'; Tasks: TOP => db:seed (See full trace by running task with --trace) Process finished with exit code 1 What is confusing me is that I am generating correct SQL as far as I can tell. In fact my code generates the SQL and I pass that to the find_by_sql function for the model, Rails itself can't be changing the SQL, or is it? SELECT * FROM admin_settings WHERE group = 'google' AND name = 'analytics_id'; I've written a lot of SQL over the years and I've looked through similar questions here. Maybe I've missed something, but I cannot see it.

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• Common methods/implementation across multiple WCF Services

  - by Rob

  I'm looking at implementing some WCF Services as part of an API for 3rd parties to access data within a product I work on. There are currently a set of services exposed as "classic" .net Web Services and I need to emulate the behaviour of these, at least in part. The existing services all have an AcquireAuthenticationToken method that takes a set of parameters (username, password, etc) and return a session token (represented as a GUID), which is then passed in on calls to any other method (There's also a ReleaseAuthenticationToken method, no guesses needed as to what that does!). What I want to do is implement multiple WCF services, such as: ProductData UserData and have both of these services share a common implementation of Acquire/Release. From the base project that is created by VS2k8, it would appear I will start with, per service: public class ServiceName : IServiceName { } public interface IServiceName { } Therefore my questions would be: Will WCF tolerate me adding a base class to this, public class ServiceName : ServiceBase, IServiceName, or does the fact that there's an interface involved mean that won't work? If "No it won't work" to Question 1, could I change IServiceName so it extends another interface, IServiceBase, thus forcing the presence of Acquire/Release methods, but then having to supply the implementation in each service. Are 1 and 2 both really bad ideas and there's actually a much better solution that, knowing next to nothing about WCF, I just haven't thought of?

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• Very fast document similarity

  - by peyton

  Hello, I am trying to determine document similarity between a single document and each of a large number of documents (n ~= 1 million) as quickly as possible. More specifically, the documents I'm comparing are e-mails; they are grouped (i.e., there are folders or tags) and I'd like to determine which group is most appropriate for a new e-mail. Fast performance is critical. My a priori assumption is that the cosine similarity between term vectors is appropriate for this application; please comment on whether this is a good measure to use or not! I have already taken into account the following possibilities for speeding up performance: Pre-normalize all the term vectors Calculate a term vector for each group (n ~= 10,000) rather than each e-mail (n ~= 1,000,000); this would probably be acceptable for my application, but if you can think of a reason not to do it, let me know! I have a few questions: If a new e-mail has a new term never before seen in any of the previous e-mails, does that mean I need to re-compute all of my term vectors? This seems expensive. Is there some clever way to only consider vectors which are likely to be close to the query document? Is there some way to be more frugal about the amount of memory I'm using for all these vectors? Thanks!

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• Writing a report

  - by wvd

  Hello all, Since some time I've been investigating more time into profiling things better, really think about how to do a thing and why. Now I'm going to start a new project, where I will be writing a report about. The report will be about anything what I wrote in the project, why, and I'll be investigating some things and do particular research about them. I've seen some reports, such as game programming in Haskell using FRP. However, after reading several reports they all seem to be build different. I have a few questions about writing a report: 1] What are the things I really should include, and what are the things I really shouldn't include? 2] Is it useful to include graphs about different methods/approaches to a several problem, where you only included one into your project, to show WHY you didn't include the other methods. Or should I just explain the method/approach used into the project. 3] Should I only be writing the report after I've completed the project, or should I also write pages about what I expect, how I'm going to build the software? Thanks, William van Doorn

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• User Defined Conversions in C++

  - by wash

  Recently, I was browsing through my copy of the C++ Pocket Reference from O'Reilly Media, and I was surprised when I came across a brief section and example regarding user-defined conversion for user-defined types: #include <iostream> class account { private: double balance; public: account (double b) { balance = b; } operator double (void) { return balance; } }; int main (void) { account acc(100.0); double balance = acc; std::cout << balance << std::endl; return 0; } I've been programming in C++ for awhile, and this is the first time I've ever seen this sort of operator overloading. The book's description of this subject is somewhat brief, leaving me with a few unanswered questions about this feature: Is this a particularly obscure feature? As I said, I've been programming in C++ for awhile and this is the first time I've ever come across this. I haven't had much luck finding more in-depth material regarding this. Is this relatively portable? (I'm compiling on GCC 4.1) Can user-defined conversions to user defined types be done? e.g. operator std::string () { /* code */ }

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• [PHP, CSS, & ?] fixed width div, resizing text on the fly based on length

  - by Andrew Heath

  Let's say you've got a simple fixed-width layout that pulls a title from a MySQL database. CSS: #wrapper { width: 800px; } h1 { width: 100%; } HTML: <html> <body> <div id="wrapper"> <h1> $titleString </h1> </div> </body> </html> But the catch is, the length of the title string pulled from your MySQL database varies wildly. Sometimes it might be 10 characters, sometimes it might be 80. It's possible to establish a min & max character count. How, if at all possible, do I get the text-size of my <h1>$titleString</h1> to enlarge/decrease on-the-fly such that the string is only ever on one line and best fit to that line length? I've seen a lot of questions about resizing the div - but in my case the div must always be 100% (800px) and I want to best-fit the title. Obviously a maximum text-size value would have to be set so 5 character strings don't become gargantuan. Does anyone have a suggestion? I'm only using PHP/MySQL/CSS on this page at the moment, but incorporation of another language is fine if it means I can solve the problem. The only thing I can think of is a bruteforce approach whereby through trial and error I establish acceptable string character count ranges matched with CSS em sizes, but that'd be a pretty ugly implementation from the code side.

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• SQL Standard Regarding Left Outer Join and Where Conditions

  - by Ryan

  I am getting different results based on a filter condition in a query based on where I place the filter condition. My questions are: Is there a technical difference between these queries? Is there anything in the SQL standard that explains the different resultsets in the queries? Given the simplified scenario: --Table: Parent Columns: ID, Name, Description --Table: Child Columns: ID, ParentID, Name, Description --Query 1 SELECT p.ID, p.Name, p.Description, c.ID, c.Name, c.Description FROM Parent p LEFT OUTER JOIN Child c ON (p.ID = c.ParentID) WHERE c.ID IS NULL OR c.Description = 'FilterCondition' --Query 2 SELECT p.ID, p.Name, p.Description, c.ID, c.Name, c.Description FROM Parent p LEFT OUTER JOIN Child c ON (p.ID = c.ParentID AND c.Description = 'FilterCondition') I assumed the queries would return the same resultsets and I was surprised when they didn't. I am using MS SQL2005 and in the actual queries, query 1 returned ~700 rows and query 2 returned ~1100 rows and I couldn't detect a pattern on which rows were returned and which rows were excluded. There were still many rows in query 1 with child rows with data and NULL data. I prefer the style of query 2 (and I think it is more optimal), but I thought the queries would return the same results.

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• Problem with LINQ to XML and Namespaces

  - by abtcabe

  I am having problems with working with a third party XML string that contains a Namespace with LINQ to XML. In the below code everything works find. I am able to select the xElement (xEl1) and update its value. 'Example Without Namespace Dim XmlWithOutNs = _ <?xml version="1.0"?> <RATABASECALC> <RATEREQUEST> <ANCHOR> <DATABASENAME>DatabaseName</DATABASENAME> <DATABASEPW>DatabasePw</DATABASEPW> </ANCHOR> </RATEREQUEST> </RATABASECALC> Dim xEl1 = XmlWithOutNs...<DATABASEPW>.FirstOrDefault If xEl1 IsNot Nothing Then xEl1.Value = "test" End If However, in the below code the xElement (xEl2) returns Nothing. The only difference is the Namespace (xmlns="http://www.cgi.com/Ratabase) 'Example With Namespace Dim XmlWithNs = _ <?xml version="1.0"?> <RATABASECALC xmlns="http://www.cgi.com/Ratabase"> <RATEREQUEST> <ANCHOR> <DATABASENAME>DatabaseName</DATABASENAME> <DATABASEPW>DatabasePw</DATABASEPW> </ANCHOR> </RATEREQUEST> </RATABASECALC> Dim xEl2 = XmlWithNs...<DATABASEPW>.FirstOrDefault If xEl2 IsNot Nothing Then xEl2.Value = "test" End If So my questions are: 1. Why is this happening? 2. How do I resolve this issue?

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• Database (and ORM) choice for an small-medium size .NET Application

  - by jim

  I have a requirement to develop a .NET-based application whose data requirements are likely to exceed the 4 gig limit of SQL 2005 Express Edition. There may be other customers of the same application (in the future) with a requirement to use a specific DB platform (such as Oracle or SQL Server) due to in-house DBA expertise. Questions What RDBMS would you guys recommend? From the looks of it the major choices are PostGreSQL, MySQL or FireBird. I've only got experience of MYSQL from these. Which ORM tool (if any) would you recommend using - ideally one that can be swapped out between DB platforms with minimal effort? I like the look of the entity framework but unsure as to the degree to which platforms other than SQL Server are supported. If it helps, we'll be using the 3.5 version of the Framework. I'm open to the idea of using a tool such as NHibernate. On the other hand, if it's going to be easier, I'm happy to write my own stored procedures / DAL code - there won't be that many tables (perhaps 30-35).

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• Please suggest other ways of communicating between server & client.

  - by Geo

  I'm writing a TCP chat server ( programming language does not mather ). It's a school project for my nephew, so it won't be released, and all questions I'm asking are just for my knowledge :). . Some of the things it will support: chatting between users ( doh ), it will be multithreaded sending each other files I know I could easily get away with all the stuff above if I go with serialization, and just send objects from client to server and back. But, if I do that, it will be limited to a specific programming language ( meaning clients written in other programming languages may not be able to deserialize the objects ). What would be the way to go so that other clients written in other languages could be supported? One way to go, off the top of my head, would be to go in this direction: the server & the client communicate by sending messages & chunks ( in lieu of other names ). Here's what I mean by this: every time the client/server wants to send something ( text message or file ) it will first send a simple text message ( newline terminated ) with the number of the chunks it will send. Example: command 4,20,30,40,50 Where command would be something like instant-message or file,4 would be the number of chunks to be sent, 20 would be the size in bytes of the first chunk, 30 of the 2nd, and so forth. after the message was sent, the client/server will start sending chunks ( of sizes mentioned in the sent message ). What do you think about implementing the client/server communication this way? What better options are there?

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• Recommendation for using equals in Entities and avoiding LazyInitializationExceptions?

  - by huxendupsel

  In the beginning there is a problem that wants to be solved. In my case i got an LazyInitializationException while using indexof in a Collection to retrieve an Object for manipulation. Here i start to think about using equals in EntityBeans (OR-Mapper at all). I know there are some discussions about overriding equals in association with OR-Mapper as hibernate like [1] Entities equals(), hashCode() and toString(). How to correctly implement them? [2] To equals and hashcode or not on entity classes, that is the question. [3] Overriding equals and hashCode in Java I currently have some entities which implements the equals but inside the code i could not use equals several times because of the LazyInitializationExceptions. So i had to workaround and use eg. the name property of the object to identify it's equality. From my point of view the whole 'LazyInitializationException-thing' is not really mentioned in this questions. I'd like to know have you got some good patterns or real live recommendations how to avoid such exception in an equal-Method. Shall i use some helper Methodes to distinguish if a Object of a class is already initialized (4) or should i apdicate the use of equals and use helper classes instead (2)? And what is about catching LazyInitializationExceptions in the equals? [Edit]: If you put equals in context with the initialization of the Object then it will gain importance. Sometimes it is nessesary to have the Object fully initialized but sometimes you don't want to. Because you just need the Object itself (name, id, ...) not its Collection-Properties. So just for equalization you have to reattach the Object and load the whole bunch you don't realy need? Are there any other solutions for such a problem?

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• Dealloc'd Predicate crashing iPhone App!

  - by DVG

  To preface, this is a follow up to an inquiry made a few days ago: http://stackoverflow.com/questions/2981803/iphone-app-crashes-when-merging-managed-object-contexts Short Version: EXC_BAD_ACCESS is crashing my app, and zombie-mode revealed the culprit to be my predicate embedded within the fetch request embedded in my Fetched Results Controller. How does an object within an object get released without an explicit command to do so? Long Version: Application Structure Platforms View Controller - Games View Controller (Predicated upon platform selection) - Add Game View Controller When a row gets clicked on the Platforms view, it sets an instance variable in Games View for that platform, then the Games Fetched Results Controller builds a fetch request in the normal way: - (NSFetchedResultsController *)fetchedResultsController{ if (fetchedResultsController != nil) { return fetchedResultsController; } //build the fetch request for Games NSFetchRequest *request = [[NSFetchRequest alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"Game" inManagedObjectContext:context]; [request setEntity:entity]; //predicate NSPredicate *predicate = [NSPredicate predicateWithFormat:@"platform == %@", selectedPlatform]; [request setPredicate:predicate]; //sort based on name NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES]; NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil]; [request setSortDescriptors:sortDescriptors]; //fetch and build fetched results controller NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:request managedObjectContext:context sectionNameKeyPath:nil cacheName:@"Root"]; aFetchedResultsController.delegate = self; self.fetchedResultsController = aFetchedResultsController; [sortDescriptor release]; [sortDescriptors release]; [predicate release]; [request release]; [aFetchedResultsController release]; return fetchedResultsController; } At the end of this method, the fetchedResultsController's _fetch_request - _predicate member is set to an NSComparisonPredicate object. All is well in the world. By the time - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section gets called, the _predicate is now a Zombie, which will eventually crash the application when the table attempts to update itself. I'm more or less flummoxed. I'm not releasing the fetched results controller or any of it's parts, and the only part getting dealloc'd is the predicate. Any ideas?

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• Linq-to-sql join/where?

  - by Curtis White

  I've the following table structures Users id Types id isBool UsersTypes userid types I want to select all the UserTypes based on id and isBool. I tried this query var q = from usertype in usertypes from type in types where type.isBool == false where userstypes.user == id select usertype; But this did not work as expected. My questions are: Why? Is there any difference in using the join on syntax vs where, where vs where cond1 && cond2? My understanding is query optimizer will optimize. Is there any difference in using where cond1 == var1 && cond2 == var2 with and without the parenthesis? This seems peculiar that it is possible to build this without parenthesis What type of query do I need in this case? I can see that I could do a subquery or use a group but not 100% sure if it is required. An example might be helpful. I'm thinking a subquery may be required in this case.

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• Interpretation of int (*a)[3]

  - by kapuzineralex

  When working with arrays and pointers in C, one quickly discovers that they are by no means equivalent although it might seem so at a first glance. I know about the differences in L-values and R-values. Still, recently I tried to find out the type of a pointer that I could use in conjunction with a two-dimensional array, i.e. int foo[2][3]; int (*a)[3] = foo; However, I just can't find out how the compiler "understands" the type definition of a in spite of the regular operator precedence rules for * and []. If instead I were to use a typedef, the problem becomes significantly simpler: int foo[2][3]; typedef int my_t[3]; my_t *a = foo; At the bottom line, can someone answer me the questions as to how the term int (*a)[3] is read by the compiler? int a[3] is simple, int *a[3] is simple as well. But then, why is it not int *(a[3])? EDIT: Of course, instead of "typecast" I meant "typedef" (it was just a typo).

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• sqlite database help

  - by mamila

  Hi all i have some questions regarding database in android. 1. in my project, I would like to create a database with single table. i would also like to insert data on this table from word or excel document. is it possible? if so please how can i do it? some code snippets would be of great help. 2. i have four different activities which i would like them to interact with this single table. the first is the main activity and its purpose is just to launch the other three activities according to user choice. so it has no interaction with the db. but the other three activities will read from the table whenever called. can you please tell me how to call the dbhelper on these activities. am kind of unable to do this.and am currently creating one db per each activity which is not the optimal way. any help is really appreciated and would be better if very soon tahnks

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• Why does Go not seem to recognize size_t in a C header file?

  - by Graeme Perrow

  I am trying to write a go library that will act as a front-end for a C library. If one of my C structures contains a size_t, I get compilation errors. AFAIK size_t is a built-in C type, so why wouldn't go recognize it? My header file looks like: typedef struct mystruct { char * buffer; size_t buffer_size; size_t * length; } mystruct; and the errors I'm getting are: gcc failed: In file included from <stdin>:5: mydll.h:4: error: expected specifier-qualifier-list before 'size_t' on input: typedef struct { char *p; int n; } _GoString_; _GoString_ GoString(char *p); char *CString(_GoString_); #include "mydll.h" I've even tried adding either of // typedef unsigned long size_t or // #define size_t unsigned long in the .go file before the // #include, and then I get "gcc produced no output". I have seen these questions, and looked over the example with no success.

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• How grouping and totaling are done into three tables using JOIN

  - by text

  Here are my tables respondents: field sample value respondentid : 1 age : 2 gender : male survey_questions: id : 1 question : Q1 answer : sample answer answers: respondentid : 1 question : Q1 answer : 1 --id of survey question I want to display all respondents who answered the certain survey, display all answers and total all the answer and group them according to the age bracket. I tried using this query: $sql = "SELECT res.Age, res.Gender, answer.id, answer.respondentid, SUM(CASE WHEN res.Gender='Male' THEN 1 else 0 END) AS males, SUM(CASE WHEN res.Gender='Female' THEN 1 else 0 END) AS females, CASE WHEN res.Age < 1 THEN 'age1' WHEN res.Age BETWEEN 1 AND 4 THEN 'age2' WHEN res.Age BETWEEN 4 AND 9 THEN 'age3' WHEN res.Age BETWEEN 10 AND 14 THEN 'age4' WHEN res.Age BETWEEN 15 AND 19 THEN 'age5' WHEN res.Age BETWEEN 20 AND 29 THEN 'age6' WHEN res.Age BETWEEN 30 AND 39 THEN 'age7' WHEN res.Age BETWEEN 40 AND 49 THEN 'age8' ELSE 'age9' END AS ageband FROM Respondents AS res INNER JOIN Answers as answer ON answer.respondentid=res.respondentid INNER JOIN Questions as question ON answer.Answer=question.id WHERE answer.Question='Q1' GROUP BY ageband ORDER BY res.Age ASC"; I was able to get the data but the listing of all answers are not present. What's wrong with my query. I want to produce something like this: ex: # of Respondents is 3 ages: 2,3 and 6 Question: what are your favorite subjects? Ages 1-4: subject 1: 1 subject 2: 2 subject 3: 2 total respondents for ages 1-4 : 2 Ages 5-10: subject 1: 1 subject 2: 1 subject 3: 0 total respondents for ages 5-10 : 1

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• Tell me again why we need both .NET and Windows? Why can't Windows morph into the CLR?

  - by le dorfier

  The same way DOS morphed into Windows? We seem to have ended up supporting and developing for three platforms from Microsoft, and I'm not sure where the boundaries are supposed to lie. Why can't the benefits of the CLR (such as type safety, memory protection, etc.) be built into Windows itself? Or into the browser? Why an entirely other virtual machine? (How may levels of virtual machine indirection are we dealing with now? We just added Silverlight - and before that Flash - running inside the Browser running inside maybe a VM install...) I can see raw Windows for servers, but why couldn't there be a CLR for workstations talking directly to the hardware (or at least not the whole Windows legacy ball and chain)? (ooppp - I've got two questions here. Let's make this - why can't .net be built into Windows? I understand about backward compatibility - but the safety of what's in .NET could be at least optionally in Windows itself, couldn't it? It would just be yet another of many sets of APIs?) Factoid - I recall that one of the competitor architectures selling against MS-DOS on the IBM PC was UCSD-pascal runtime - a VM.

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