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  • Adding methods to an Objective C class interface is optional?

    - by Steve the Plant
    Coming from a C++ background, one thing that confuses me about Objective C is the fact that you can add a method to a class without actually specifying it in the class interface. So I had a barrage of questions: Why would someone choose to not add the method in the class interface? Is it simply because of visibility? Methods without a declaration in the interface are private? Is declaring methods in a class interface just optional? Is it different for overriding a base class' method?

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  • Multiset of shared_ptrs as a dynamic priority queue: Concept and practice

    - by Sarah
    I was using a vector-based priority queue typedef std::priority_queue< Event, vector< Event >, std::greater< Event > > EventPQ; to manage my Event objects. Now my simulation has to be able to find and delete certain Event objects not at the top of the queue. I'd like to know if my planned work-around can do what I need it to, and if I have the syntax right. I'd also like to know if dramatically better solutions exist. My plan is to make EventPQ a multiset of smart pointers to Event objects: typedef std::multi_set< boost::shared_ptr< Event > > EventPQ; I'm borrowing functions of the Event class from a related post on a multimap priority queue. // Event.h #include <cstdlib> using namespace std; #include <set> #include <boost/shared_ptr.hpp> class Event; typedef std::multi_set< boost::shared_ptr< Event > > EventPQ; class Event { public: Event( double t, int eid, int hid ); ~Event(); void add( EventPQ& q ); void remove(); bool operator < ( const Event & rhs ) const { return ( time < rhs.time ); } bool operator > ( const Event & rhs ) const { return ( time > rhs.time ); } double time; int eventID; int hostID; EventPQ* mq; EventPQ::iterator mIt; }; // Event.cpp Event::Event( double t, int eid, int hid ) { time = t; eventID = eid; hostID = hid; } Event::~Event() {} void Event::add( EventPQ& q ) { mq = &q; mIt = q.insert( boost::shared_ptr<Event>(this) ); } void Event::remove() { mq.erase( mIt ); mq = 0; mIt = EventPQ::iterator(); } I was hoping that by making EventPQ a container of pointers, I could avoid wasting time copying Events into the container and avoid accidentally editing the wrong copy. Would it be dramatically easier to store the Events themselves in EventPQ instead? Does it make more sense to remove the time keys from Event objects and use them instead as keys in a multimap? Assuming the current implementation seems okay, my questions are: Do I need to specify how to sort on the pointers, rather than the objects, or does the multiset automatically know to sort on the objects pointed to? If I have a shared_ptr ptr1 to an Event that also has a pointer in the EventPQ container, how do I find and delete the corresponding pointer in EventPQ? Is it enough to .find( ptr1 ), or do I instead have to find by the key (time)? Is the Event::remove() sufficient for removing the pointer in the EventPQ container? There's a small chance multiple events could be created with the same time (obviously implied in the use of multiset). If the find() works on event times, to avoid accidentally deleting the wrong event, I was planning to throw in a further check on eventID and hostID. Does this seem reasonable? (Dumb syntax question) In Event.h, is the declaration of dummy class Event;, then the EventPQ typedef, and then the real class Event declaration appropriate? I'm obviously an inexperienced programmer with very spotty background--this isn't for homework. Would love suggestions and explanations. Please let me know if any part of this is confusing. Thanks.

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  • Is it possible to programmatically control c# health monitoring without using the web.config file?

    - by Adam
    I have developed my own custom provider for the health monitoring; however, I use parameters in the constructor and this is not allowed when using the health monitoring from the web.config file. Does anyone know if I can turn on/off the monitoring and have it watch properly through code (possibly in my global.asax file on application startup). Or, is it possible for me to create my own watcher that will do the same thing as the health monitor. Or, finally - can I just pass variables from the web.config setup (i'm not familiar with the public token part of the provider type declaration). Thanks in advance

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  • iPhone SDK 3.0 deprecation of UITableViewCell .text

    - by djt9000
    Came across an SDK3.0 deprecation that I am having a bit of trouble tryinig to figure out. If my declaration of @property (nonatomic, retain) UIImage *rowImage; does not work, nor @property (nonatomic, readonly, retain) UIImage *rowImage; and I @synthesize rowImage; Do I need to write my own setter because @synthesize will not properly handle this? cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:RootViewControllerCell] autorelease]; // Dpericated in SDK 3.0 // //cell.text = controller.title; //cell.image = controller.rowImage; // Using what the documentation says to use Error=== cell.textLabel = controller.title; Error=== cell.imageView = controller.rowImage; Error: Object cannot be set - Either readonly property or no setter found. Hope this makes sense, any help would be appreciated.

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  • Incremental Compilation in Eclipse. ASTNode-s and SVN versioning

    - by Alex
    Hi there, I am building up some statistics after analyzing the source code in eclipse. But the overall process is too slow because i rebuild my model every time from scratch after each compilation. I am looking for a way to get only the changed parts of the code (as ASTNodes) and to rebuild just that part of my model. I suppose that even the changed compilation units and not the exact code elements would be enough after the user compiles and still would be a nice optimization. I am sure eclipse is capable of knowing what code elements are changed (and even to know their semantics), because when I use the subclipse plugin my changes are ordered by a code element (an import, a method, a variable declaration, etc). Well.. at least that plugin is capable of knowing that info. Thanks in advance

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  • Incompatible Types in Initialization

    - by jack
    I have the following code in a subroutine that produces an incompatible types in initialization error on the varVal library in the subroutine evaluateExpression: NSDictionary *varVal; for (int i=0; i<varCount; i++) { [varVal setObject:[(i+1)*2 stringValue] forKey:[i stringValue]]; } double result =[[self brain] evaluateExpression:[[self brain] expression] usingVariableValues:varVal]; My subroutine declaration in the brain.h file is: +(double)evaluateExpression:(id)anExpression usingVariableValues:(NSDictionary *)variables; I'd appreciate any help.

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  • FindBugs and CheckForNull on classes vs. interfaces

    - by ndn
    Is there any way to let FindBugs check and warn me if a CheckForNull annotation is present on the implementation of a method in a class, but not on the declaration of the method in the interface? import javax.annotation.CheckForNull; interface Foo { public String getBar(); } class FooImpl implements Foo { @CheckForNull @Override public String getBar() { return null; } } public class FindBugsDemo { public static void main(String[] args) { Foo foo = new FooImpl(); System.out.println(foo.getBar().length()); } } I just discovered a bug in my application due to a missing null check that was not spotted by FindBugs because CheckForNull was only present on FooImpl, but not on Foo, and I don't want to spot all other locations of this problem manually.

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  • XML Schema Header & Namespace Config

    - by zharvey
    Migrating from DTD to XSD and for some reason the transition is a bumpy one. I understand how to define the schema once I'm inside the <xs:schema> root tag, but getting past the header & namespace declaration stuff is proving to be especially confusing for me. I have been trying to follow the well-laid out tutorial on W3S but even that tutorial seems to assume a lot of knowledge up front. I guess what I'm looking for is a King's English explanation of which attributes do what, where they go, and why: xmlns xmlns:xs xmlns:xsi targetNamespace xsi:schemaLocation And in some cases I see different variations of these elements/attributes, such as xsi which seems to have two different notations like xsi:schemaLocation="..." and xs:import schemaLocation="...". I guess between all these slight variations I can't seem to make heads or tails of what each of these does. Thanks in advance for bringing any clarity to this confusion!

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  • iPhone - a question about @property

    - by Roger
    Hi, I am kind of newbie on Objective-C and I was looking at a code, trying to understand a few things, and I come across with this .h file: there was a declaration like that on the @interface section MyVideoClass *contrast_; then below we have @property (nonatomic, retain) MyVideoClass *contrast; @property (nonatomic, retain) FetchClass *fetchMe; The strange part is that the first has an underscrore after the name and the second one, doesn't. The other strange thing is that the guy has a call to these properties like this: FetchClass *fetchOne = [self.fetchMe contrast]; What kind of call is that? This seems pretty insane to me. I simply cannot understand what is going on here, but the code works. pretty insane. Can you guys explain me that? Forgive the stupid question, but I am still learning... thanks

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  • NSTextField doesn't display text

    - by Alexsander Akers
    The NSTextField has a superview and a frame. It is fully visible and has the following declaration: - (id) initWithFrame: (NSRect) frameRect { if ((self = [super initWithFrame: NSMakeRect(0, 0, 300, 20)])) { label = [[NSTextField alloc] initWithFrame: NSMakeRect(47, 1, 233, 18)]; [[label cell] setAllowsUndo: NO]; [[label cell] setLineBreakMode: NSLineBreakByTruncatingMiddle]; [[label cell] setScrollable: NO]; [label setBezeled: NO]; [label setBordered: NO]; [label setDrawsBackground: NO]; [label setEditable: NO]; [label setFont: [NSFont menuFontOfSize: 14.0f]]; [label setSelectable: NO]; [label setTextColor: [NSColor textColor]]; [self addSubview: label]; NSLog(@"%@", NSStringFromRect([label visibleRect])); } return self; }

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  • Java Enum Newbie Question

    - by ikurtz
    i have a situation where i need the Checker enum below used in multiple classes: package Sartre.Connect4; public enum Checker { EMPTY, RED, YELLOW } so i put the Checker in a Checker.java file and then from the classes that need it i simply do the following: example: public Cell(){ currentCell = Checker.EMPTY; } example: public Cell(Checker checker){ currentCell = checker; } and the code compiles fine and runs fine also. so what is my question? well being new to Java i am just wondering if the way i use Checker without encapsulating it in a class is a sound implementation? it may be because of The enum declaration defines a class (called an enum type). as noted in Java docs enum tutorial page. thank you for your insight into this matter.

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  • PHP Global variable in class is reset

    - by Robert
    I have a web form that manipulates records in a MySQL database. I have a method for displaying an edit interface for both creating new records and editing them if ($_POST['new_page']) { print "<h2>Create new page</h2>\n"; $isNew=1; $this->EditForm(); } else if($_POST['edit']){ print "<h2>Edit page</h2>\n"; $isNew=0; $this->EditForm(); } I am trying to use the global variable $isNew to determine where a record is to be added or updated. However, whenever my SaveChanges() function is run, $isNew is always 0. $isNew is declared immediately after the class declaration, outside all of the functions. class Editor{ public $isNew;

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  • Php code not executing - dies out when trying to refer to member of static class - no error displaye

    - by Ali
    I'm having some problems with this piece of code. I've included a class declaration and trying to create an object of that class but my code dies out. It doesn't seem to be an include issue as all the files are being included even the files called for inclusion within the class file itself. However the object is not created - I tried to put an echo statement in the __construct function but nothing it just doesn't run infact doesn't create the object and the code won't continue from there - plus no error is reported or displayed and I have error reporting set to E_ALL and display errors set to true WHats happening here :( =============EDIT SOrry I checked again the error is prior to teh object creation thing - it dies out when it tries to refer to a constant in a static class like so: $v = Zend_Oauth::REQUEST_SCHEME_HEADER; THis is the class or part of it - it has largely static functions its the Zend Oauth class: class Zend_Oauth { const REQUEST_SCHEME_HEADER = 'header'; const REQUEST_SCHEME_POSTBODY = 'postbody'; const REQUEST_SCHEME_QUERYSTRING = 'querystring'; // continued LIke I said no error is being reported at all :(

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  • Why does the HTML5 DOCTYPE mess with my padding?

    - by Dakota
    I have an html5 page with a navbar. Completely scratch coded. I just recently added a doctype to the item, and now I’m getting extra space under my navbar. If I remove the doctype declaration, it goes back to normal. I have completely reset padding, margins, etc. on everything, and cut it down to the a small amount of code that illustrates the issue. The page can be seen at http://hackthetruth.org/webdesign/broken Does anyone know why declaring the doctype is messing with the height of a div?

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  • When is @uncheckedVariance needed in Scala, and why is it used in GenericTraversableTemplate?

    - by retronym
    @uncheckedVariance can be used to bridge the gap between Scala's declaration site variance annotations and Java's invariant generics. scala import java.util.Comparator import java.util.Comparator scala trait Foo[T] extends Comparator[T] defined trait Foo scala trait Foo[-T] extends Comparator[T] :5: error: contravariant type T occurs in invariant position in type [-T]java.lang.Object with java.util.Comparator[T] of trait Foo trait Foo[-T] extends Comparator[T] ^ scala import annotation.unchecked._ import annotation.unchecked._ scala trait Foo[-T] extends Comparator[T @uncheckedVariance] defined trait Foo This says that java.util.Comparator is naturally contra-variant, that is the type parameter T appears in parameters and never in a return type. Which begs the question, why is it also used in the Scala collections library: trait GenericTraversableTemplate[+A, +CC[X] <: Traversable[X]] extends HasNewBuilder[A, CC[A] @uncheckedVariance] What are the valid uses for this annotation?

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  • syntax error, unexpected '.', expecting ')'

    - by Jonathan
    Hi, I've got a problem when I'm calling a static var from another class. I get this pretty syntax error where php is unexpected the '.' Here is where I'm calling it : private $aLien = array( "menu1" => array("Accueil","statique/".Variable_init::$langue."/accueil.html",0,0), //This line "menu2" => array("Infos Pratiques","statique/".Variable_init::$langue."/info.html",0,0), "menu3" => array("Faire une réservation","statique/".Variable_init::$langue."/reserver.html",0,0), "menu4" => array("Pour Nous Joindre","statique/".Variable_init::$langue."/nousJoindre.html",0,0), "menu5" => array("Plan du site","statique/".Variable_init::$langue."/plansite.html",0,0) ); And here is my static var declaration from another class: class Variable_init implements iVariable_init{ public static $langue; public static $id_choix; public static $id_contenu;

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  • Expected Class-name before { token

    - by ML
    Hi All, I am trying to figure out whey I get an error: expected class-name before { token Here is the relative source to the error: #pragma once #ifndef H_FXACTION #define H_FXACTION #include "CP_M_RefCounted.h" #include "FxTypes.h" #include "string" #include "FxString.h" #include "FxPixels.h" #include "CP_Rect.h" #include "FxStreamable.h" #include "FxPoint.h" #include "FxPtr.h" #include "FxImage.h" #include "FxSleekStreaming.h" typedef FxID FxActionType; typedef FxUInt32 FxActionID; FxActionID FrMakeUniqueActionID(void); class FxActionData; class FxActionData : public CP_M_RefCounted { public: FxActionData(); FxActionData(FxBool final) :mFinal(final) { } virtual ~FxActionData(); I get the error at this line: class FxActionData : public CP_M_RefCounted What I dont get is why the line: class FxActionData; is there when you are creating the class directly under it. Isn't this a forward declaration? What things could be going on here?

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  • Why must use "out" instead of ref ?

    - by Phsika
    i wrote some code blocks about ref -out declaration. i think that ref is most useful out. Ok. why i need to use out. i can use always ref everytime: namespace out_ref { class Program { static void Main(string[] args) { sinifA sinif = new sinifA(); int test = 100; sinif.MethodA(out test); Console.WriteLine(test.ToString()); sinif.MethodB(ref test); Console.WriteLine(test.ToString()); Console.ReadKey(); } } class sinifA { public void MethodA(out int a) { a = 200; } int _b; public void MethodB(ref int b) { _b = b; b = 2*b; } } }

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  • NSMutableArray in appdelegate - EXEC_BAD_ACCESS

    - by Tejaswi Yerukalapudi
    Hi, I'm trying to use a global array in the appdelegate as a quick fix for a demo I'm building. The relevant code for this .h file has the declaration { NSMutableArray *trnEntered; } @property (nonatomic, retain) NSMutableArray *trnEntered .m file has the following code - trnEntered = [[NSMutableArray alloc] init]; NSLog(@"%@",[trnEntered count]); // prints null. [trnEntered addObject:@"1"]; NSLog(@"%@",[trnEntered count]); // exec bad access. Not sure where I'm going wrong here. Looks fairly straight forward. Thanks for the help in advance, Teja.

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  • Don't understand multiple parameter declarations in objective-c

    - by Blankman
    can someone clarify this for me: When there’s more than one argument, the arguments are declared within the method name after the colons. Arguments break the name apart in the declaration, just as in a message. For example: - (void)setWidth:(float)width height:(float)height; So in the above: method is for instance variables returns void parameter#1 is a float, named width. parameter#2 is a float,named height. But why is it hieght:(float)height; and not just: - (void)setWidth: (float)width (float)height;

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  • How to resolve parse error in Splint

    - by Thi
    Splint is not continuing it's checking after finding parse errors. I've tried with +trytorecover option also but no change. Please let me know on how to use +trytorecover to make Splint attempt to continue after a parse error. Here is what I'm receiving, 161: splint +trytorecover spy.c Splint 3.1.1 --- 19 Jul 2006 spy.c:41:12: Parse Error: Non-function declaration: byte_4 : int. Attempting to continue. spy.c:41:12: Cannot recover from parse error. *** Cannot continue.

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  • Question on preprocessor directives

    - by dotnetdev
    If I use proprocessor directives to define which code an OS will run, like so: #if winXP // Compiling for Windows XP platformName = "Microsoft Windows XP"; #elif win2000 // Compiling for Windows 2000 platformName = "Microsoft Windows 2000"; #elif win7 // Compiling for Windows 7 platformName = "Microsoft Windows 7"; #else // Unknown platform specified platformName = "Unknown"; How does the system pick up which OS is being used? This is an example from the book Visual C# 2010 Recipes, where the author says that the platformName variable (declaration ommitted), wil equal the OS above. Thanks

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  • C++ operator overloading doubt

    - by avd
    I have a code base, in which for Matrix class, these two definitions are there for () operator: template <class T> T& Matrix<T>::operator() (unsigned row, unsigned col) { ...... } template <class T> T Matrix<T>::operator() (unsigned row, unsigned col) const { ...... } One thing I understand is that the second one does not return the reference but what does const mean in the second declaration. Also which function is called when I do say mat(i,j)

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  • RoR model field without validators, has*, delegates, etc

    - by jackr
    How can I declare a field, in the Rails model, when it doesn't have any "has_" relations, or validations, or delegations? I just need to ensure its existence and column width in the schema. Currently, I have no mention of the field in the "schema section" of the model file, but it's referenced in various methods that use it, and this seems to work. However, depending on my exact creation workflow, the underlying database table may be created as t.binary "field_name", :limit => 32 or t.binary "field_name", :limit => 255 This is not a restriction on the value (any binary value is valid, even NULL), only on the table column declaration. As it happens, 32 is enough -- it never receives any larger value, it's only ever written to like this: self.field_name = SecureRandom.random_bytes(32)

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  • Generic Interface with property

    - by pranay
    i have one interface /// <summary> /// Summary description for IBindable /// </summary> public interface IBindable<T> { // Property declaration: T Text { get; set; } } Now i want to implement this interface in my class public class MyTextBox :IBindable<string> { //now i how can i implement Text peroperty here } I don't want to implement it like string IBindable<string>.Text { get { return "abc";} set { //assigne value } } i want to implement it like public string Text {get{} set {}}

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