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  • (type theoretical) How is ([] ==) [] typed in haskell?

    - by Ingo
    It sounds silly, but I can't get it. Why can the expression [] == [] be typed at all? More specifically, which type (in class Eq) is inferred to the type of list elements? In a ghci session, I see the following: Prelude> :t (==[]) (==[]) :: (Eq [a]) => [a] -> Bool But the constraint Eq [a] implies Eq a also, as is shown here: Prelude> (==[]) ([]::[IO ()]) <interactive>:1:1: No instance for (Eq (IO ())) arising from use of `==' at <interactive>:1:1-2 Probable fix: add an instance declaration for (Eq (IO ())) In the definition of `it': it = (== []) ([] :: [IO ()]) Thus, in []==[], the type checker must assume that the list element is some type a that is in class Eq. But which one? The type of [] is just [a], and this is certainly more general than Eq a = [a].

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  • Objective-C : enum like Java (int values and many others for each enum)

    - by Oliver
    In Java, you can make an enum having multiples values. In objective-C, this cannot be done easily. I've read many pages about this but I didn't found anything satisfying that would allow me to use enums by a simple way and to keep the enum declaration and their different values in the same file. I would like to write something like this in a enums.h : // ======================================== typedef enum {eRED, eGREEN, eBLUE} ColorEnum; int colorValues[] = { 0xFF0000, 0x00FF00, 0x0000FF }; NSArray *colorNames = [NSArray arrayWithObjects:@"Red color", @"light green", @"Deep blue", nil]; // ======================================== and be able to use thoses global variables to manage my stuff anywhere like : int color = colorValues[eRED]; But I don't know how to write this. I have compile errors like "ColorValues" is defines many times. Or if I just use "static", I have many "ColorValues" not used in .m file... Could you help me ?

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  • How to determine whether a class has a particular templated member function?

    - by Aozine
    I was wondering if it's possible to extend the SFINAE approach to detecting whether a class has a certain member function (as discussed here: "Is there a Technique in C++ to know if a class has a member function of a given signature?" http://stackoverflow.com/questions/87372/is-there-a-technique-in-c-to-know-if-a-class-has-a-member-function-of-a-given-s ) to support templated member functions? E.g. to be able to detect the function foo in the following class: struct some_class { template < int _n > void foo() { } }; I thought it might be possible to do this for a particular instantiation of foo, (e.g. check to see if void foo< 5 >() is a member) as follows: template < typename _class, int _n > class foo_int_checker { template < typename _t, void (_t::*)() > struct sfinae { }; template < typename _t > static big test( sfinae< _t, &_t::foo< _n > > * ); template < typename _t > static small test( ... ); public: enum { value = sizeof( test< _class >( 0 ) ) == sizeof( big ) }; }; Then do foo_int_checker< some_class, 5 >::value to check whether some_class has the member void foo< 5 >(). However on MSVC++ 2008 this always returns false while g++ gives the following syntax errors at the line test( sfinae< _t, &_t::foo< _n > > ); test.cpp:24: error: missing `>' to terminate the template argument list test.cpp:24: error: template argument 2 is invalid test.cpp:24: error: expected unqualified-id before '<' token test.cpp:24: error: expected `,' or `...' before '<' token test.cpp:24: error: ISO C++ forbids declaration of `parameter' with no type Both seem to fail because I'm trying to get the address of a template function instantiation from a type that is itself a template parameter. Does anyone know whether this is possible or if it's disallowed by the standard for some reason? EDIT: It seems that I missed out the ::template syntax to get g++ to compile the above code correctly. If I change the bit where I get the address of the function to &_t::template foo< _n > then the program compiles, but I get the same behaviour as MSVC++ (value is always set to false). If I comment out the ... overload of test to force the compiler to pick the other one, I get the following compiler error in g++: test.cpp: In instantiation of `foo_int_checker<A, 5>': test.cpp:40: instantiated from here test.cpp:32: error: invalid use of undefined type `class foo_int_checker<A, 5>' test.cpp:17: error: declaration of `class foo_int_checker<A, 5>' test.cpp:32: error: enumerator value for `value' not integer constant where line 32 is the enum { value = sizeof( test< _class >( 0 ) ) == sizeof( big ) }; line. Unfortunately this doesn't seem to help me diagnose the problem :(. MSVC++ gives a similar nondescript error: error C2770: invalid explicit template argument(s) for 'clarity::meta::big checker<_checked_type>::test(checker<_checked_type>::sfinae<_t,&_t::template foo<5>> *)' on the same line. What's strange is that if I get the address from a specific class and not a template parameter (i.e. rather than &_t::template foo< _n > I do &some_class::template foo< _n >) then I get the correct result, but then my checker class is limited to checking a single class (some_class) for the function. Also, if I do the following: template < typename _t, void (_t::*_f)() > void f0() { } template < typename _t > void f1() { f0< _t, &_t::template foo< 5 > >(); } and call f1< some_class >() then I DON'T get a compile error on &_t::template foo< 5 >. This suggests that the problem only arises when getting the address of a templated member function from a type that is itself a template parameter while in a SFINAE context. Argh!

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  • not returning anything from postgresql function?

    - by netllama
    Is it possible for a PostgreSQL plpgsql function to not return anything? I've created a function, and I don't need it to return anything at all, as it performs a complex SQL query, and inserts the results of that query into another table (SELECT INTO ....). Thus, I have no need or interest in having the function return any output or value. Unfortunately, when I try to omit the RETURN clause of the function declaration, I can't create the function. Is it possible for a PostgreSQL plpgsql function to not return anything?

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  • Trying to use SHCreateShellItem, having #include issues

    - by dreamlax
    There is a function in called SHCreateShellItem which is declared in <shlobj.h>, but it has been #ifdef'd out based on whether or not _WIN32_IE is greater than or equal to 0x601 (if it is, then the declaration is present). However, even when I define _WIN32_IE to 0x601 before I include <shlobj.h>, MSVC++ still complains that SHCreateShellItem is undeclared. For example, I cannot get the following to compile: #define _WIN32_IE 0x601 #include <shlobj.h> int someFunction (LPITEMIDLIST parent, LPITEMIDLIST child) { HRESULT result; IShellItem *shellObj; result = SHCreateShellItem (parent, NULL, child, &shellObj); if (SUCCEEDED(result)) { // do stuff } return SUCCEEDED(result); } Do I need to define _WIN32_IE in a different way?

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  • Function matching in Qt

    - by Alexander
    Hello, I have some trouble with Qt. I have a class 'Core' class Core { public: static QString get_file_content(QString filename); static void setMainwindow(MainWindow *w); private: static MainWindow *main_window; }; and class 'MainWindow' in namespace Ui: namespace Ui { class MainWindow; } class MainWindow : public QMainWindow { Q_OBJECT public: MainWindow(QWidget *parent = 0); ~MainWindow(); private: Ui::MainWindow *ui; }; In MainWindow constructor I make MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui->setupUi(this); Core::setMainwindow(this); } and gets error mainwindow.cpp:8: error: no matching function for call to 'Core::setMainwindow(MainWindow* const)' Of cource, i include core.h with declaration of 'Core' class. That's occurs only on setMainwindow method. So the questions is - why Core class method setMainwindow() is invisible in MainWindow class?

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  • Some help with basic Sound functions in actionscript 3

    - by danwoods
    Hello all. I'm working on a mp3 player and I'm super new at all things flash so there are lots of questions. Currently I'm getting stuck on the track change. My variable declaration look like this: var index:int = -1; var music:Sound = new Sound(new URLRequest("moe2008-05-24d02t02_vbr.mp3")); var sc:SoundChannel; var isPlaying:Boolean = false; and my change track function looks like this: function changeTrack(newTrack){ sc.stop(); isPlaying = false; music = new Sound(new URLRequest(newTrack)); sc = music.play(); isPlaying = true; index++; } Does anyone see any obvious errors??? Thanks

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  • login form whith java/sqlite

    - by tuxou
    hi I would like to create a login form for my application with the possibility to add or remove users for an sqlite database, i have created the table users(nam, pass) but i can't unclud it in my login form, it someone could help me this is my login code: import java.awt.*; import java.awt.event.*; import javax.swing.*; public class login extends JFrame { // Variables declaration private JLabel jLabel1; private JLabel jLabel2; private JTextField jTextField1; private JPasswordField jPasswordField1; private JButton jButton1; private JPanel contentPane; // End of variables declaration public login() { super(); create(); this.setVisible(true); } private void create() { jLabel1 = new JLabel(); jLabel2 = new JLabel(); jTextField1 = new JTextField(); jPasswordField1 = new JPasswordField(); jButton1 = new JButton(); contentPane = (JPanel)this.getContentPane(); // // jLabel1 // jLabel1.setHorizontalAlignment(SwingConstants.LEFT); jLabel1.setForeground(new Color(0, 0, 255)); jLabel1.setText("username:"); // // jLabel2 // jLabel2.setHorizontalAlignment(SwingConstants.LEFT); jLabel2.setForeground(new Color(0, 0, 255)); jLabel2.setText("password:"); // // jTextField1 // jTextField1.setForeground(new Color(0, 0, 255)); jTextField1.setSelectedTextColor(new Color(0, 0, 255)); jTextField1.setToolTipText("Enter your username"); jTextField1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { jTextField1_actionPerformed(e); } }); // // jPasswordField1 // jPasswordField1.setForeground(new Color(0, 0, 255)); jPasswordField1.setToolTipText("Enter your password"); jPasswordField1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { jPasswordField1_actionPerformed(e); } }); // // jButton1 // jButton1.setBackground(new Color(204, 204, 204)); jButton1.setForeground(new Color(0, 0, 255)); jButton1.setText("Login"); jButton1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { jButton1_actionPerformed(e); } }); // // contentPane // contentPane.setLayout(null); contentPane.setBorder(BorderFactory.createEtchedBorder()); contentPane.setBackground(new Color(204, 204, 204)); addComponent(contentPane, jLabel1, 5,10,106,18); addComponent(contentPane, jLabel2, 5,47,97,18); addComponent(contentPane, jTextField1, 110,10,183,22); addComponent(contentPane, jPasswordField1, 110,45,183,22); addComponent(contentPane, jButton1, 150,75,83,28); // // login // this.setTitle("Login To Members Area"); this.setLocation(new Point(76, 182)); this.setSize(new Dimension(335, 141)); this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); this.setResizable(false); } /** Add Component Without a Layout Manager (Absolute Positioning) */ private void addComponent(Container container,Component c,int x,int y,int width,int height) { c.setBounds(x,y,width,height); container.add(c); } private void jTextField1_actionPerformed(ActionEvent e) { } private void jPasswordField1_actionPerformed(ActionEvent e) { } private void jButton1_actionPerformed(ActionEvent e) { System.out.println("\njButton1_actionPerformed(ActionEvent e) called."); String username = new String(jTextField1.getText()); String password = new String(jPasswordField1.getText()); if(username.equals("") || password.equals("")) // If password and username is empty Do this { jButton1.setEnabled(false); JLabel errorFields = new JLabel("You must enter a username and password to login."); JOptionPane.showMessageDialog(null,errorFields); jTextField1.setText(""); jPasswordField1.setText(""); jButton1.setEnabled(true); this.setVisible(true); } else { JLabel optionLabel = new JLabel("You entered "+username+" as your username. Is this correct?"); int confirm =JOptionPane.showConfirmDialog(null,optionLabel); switch(confirm){ // Switch Case case JOptionPane.YES_OPTION: // Attempt to Login user jButton1.setEnabled(false); // Set button enable to false to prevent 2 login attempts break; case JOptionPane.NO_OPTION: // No Case.(Go back. Set text to 0) jButton1.setEnabled(false); jTextField1.setText(""); jPasswordField1.setText(""); jButton1.setEnabled(true); break; case JOptionPane.CANCEL_OPTION: // Cancel Case.(Go back. Set text to 0) jButton1.setEnabled(false); jTextField1.setText(""); jPasswordField1.setText(""); jButton1.setEnabled(true); break; } // End Switch Case } } public static void main(String[] args) { JFrame.setDefaultLookAndFeelDecorated(true); JDialog.setDefaultLookAndFeelDecorated(true); try { UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); } catch (Exception ex) { System.out.println("Failed loading L&F: "); System.out.println(ex); } new login(); }; }

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  • ASP.NET 1.0 site error after upgrade to VS.NET 2010

    - by Keith
    Help. I installed VS.NET 2010 and now my existing ASP.NET MVC application won't run. I checked that the 1.0 version of System.Web.Mvc is still referenced but when I browse my application, I get an error like this: "Compiler Error Message: CS1579: foreach statement cannot operate on variables of type 'object' because 'object' does not contain a public definition for 'GetEnumerator'". My partial view has this declaration: <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<List<ProductModel" %> //various import statements <div <% foreach (var category in Model.Categories) { % <span<%= category.Name %</span <span<%= category.Market%</span <% } % </div For what it's worth, the source view shows ViewUserControl in red and gives a tool tip reading "Cannot resolve symbol 'ViewUserControl'". My working code didn't change, the only delta is that I upgraded to VS.NET 2010 (which includes MVC 2.0); I'm sure something is not referenced correctly but I cannot figure out what's going on.

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  • iPhone: custom UITableViewCell with Interface Builder -> how to release cell objects?

    - by Stefan Klumpp
    The official documentation tells me I've to do these 3 things in order to manage the my memory for "nib objects" correctly. @property (nonatomic, retain) IBOutlet UIUserInterfaceElementClass *anOutlet; "You should then either synthesize the corresponding accessor methods, or implement them according to the declaration, and (in iPhone OS) release the corresponding variable in dealloc." - (void)viewDidUnload { self.anOutlet = nil; [super viewDidUnload]; } That makes sense for a normal view. However, how am I gonna do that for a UITableView with custom UITableViewCells loaded through a .nib-file? There the IBOutlets are in MyCustomCell.h (inherited from UITableViewCell), but that is not the place where I load the nib and apply it to the cell instances, because that happens in MyTableView.m So do I still release the IBOutlets in the dealloc of MyCustomCell.m or do I have to do something in MyTableView.m? Also MyCustomCell.m doesn't have a - (void)viewDidUnload {} where I can set my IBOutlets to nil, while my MyTableView.m does.

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  • Copy constructor with more than one parameter

    - by Ravi Gupta
    I am learning C++ and was reading copy constructor from the C++: The Complete Reference. The books says that It is permissible for a copy constructor to have additional parameters as long as they have default arguments defined for them. However, in all cases the first parameter must be a reference to the object doing the initializing. But I am confused that how we are going to pass those additional parameters? I am sure there should be some way which is not given in the book and which I am unable to figure out. Can anyone help me out? EDIT: Also is it possible to pass these extra parameters in all three cases i.e. ¦ When one object explicitly initializes another, such as in a declaration ¦ When a copy of an object is made to be passed to a function ¦ When a temporary object is generated (most commonly, as a return value)

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  • inheritance and hidden overloads

    - by Caspin
    The following code doesn't compile. struct A {}; struct B {}; class Base { public: virtual void method( A param ) { } virtual void method( B param ) = 0; }; class Derived : public Base { public: //using Base::method; void method( B param ) { } }; int main() { Derived derived; derived.method(A()); } The compiler can't find the overload of method() that has an A parameter. The 'fix' is to add a using declaration in the derived class. My question is why. What is the rational for a weird language rule like this? I verified the error in both GCC and Comeau, so I assume this isn't a compiler bug but a feature of the language. Comeau at least gives me this warning: "ComeauTest.c", line 10: warning: overloaded virtual function "Base::method" is only partially overridden in class "Derived" class Derived : public Base ^

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  • Effects of the `extern` keyword on C functions

    - by Elazar Leibovich
    In C I did not notice any effect of the extern keyword used before function declaration. At first I thougth that when defining extern int f(); in a single file forces you to implement it outside of the files scope, however I found out that both extern int f(); int f() {return 0;} And extern int f() {return 0;} Compiles just fine, with no warnings from gcc. I used gcc -Wall -ansi, he wouldn't even accept // comments. Are there any effects for using extern before function definitions? Or is it just an optional keyword with no side effects for functions. In the latter case I don't understand why did the standard designers chose to litter the grammar with superfluous keywords. EDIT: to clarify, I know there's usage for extern in variables, but I'm only asking about extern in functions.

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  • In Elixir or SQLAlchemy, is there a way to also store a comment for a/each field in my entities?

    - by kchau
    Our project is basically a web interface to several systems of record. We have many tables mapped, and the names of each column aren't as well named and intuitive as we'd like... The users would like to know what data fields are available (i.e. what's been mapped from the database). But, it's pointless to just give them column names like: USER_REF1, USER_REF2, etc. So, I was wondering, is there a way to provide a comment in the declaration of my field? E.g. class SegregationCode(Entity): using_options(tablename="SEGREGATION_CODES") segCode = Field(String(20), colname="CODE", ... primary_key=True) #Have a comment attr too? If not, any suggestions?

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  • var keyword without 'using someNamespace'

    - by RichK
    How does Visual Studio/intellisense know what to do with a variable declared as var even if you don't include the necessary using declaration at the top? For example, I have class MyDomainObject defined in a different namespace If I don't declare using TheOtherNameSpace; in the file the following code won't compile: private void Foo() { MyDomainObject myObj = new MyDomainObject(); // Doesn't know what this class is } But if I use var var myObj = new MyDomainObject(); This will compile, and intellisense knows exactly what I can with it. So how the heck does it know what the type is without the using? (And as an aside, if it knows without the using, why do we need usings at all?!)

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  • Pros and Cons of Different macro function / inline methods in C

    - by Robert S. Barnes
    According to the C FAQ, there are basically 3 practical methods for "inlining" code in C: #define MACRO(arg1, arg2) do { \ /* declarations */ \ stmt1; \ stmt2; \ /* ... */ \ } while(0) /* (no trailing ; ) */ or #define FUNC(arg1, arg2) (expr1, expr2, expr3) To clarify this one, the arguments are used in the expressions, and the comma operator returns the value of the last expression. or using the inline declaration which is supported as an extension to gcc and in the c99 standard. The do { ... } while (0) method is widely used in the Linux kernel, but I haven't encountered the other two methods very often if at all. I'm referring specifically to multi-statement "functions", not single statement ones like MAX or MIN. What are the pros and cons of each method, and why would you choose one over the other in various situations?

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  • Add XSLT 2 schema to Visual Studio 2010 for intellisense

    - by David Merrilees
    I'd like to add the XSLT 2 schema to Visual Studio 2010 to provide intellisense. I've added the schema to C:\Program Files\Microsoft Visual Studio 10.0\Xml\Schemas (removing the XSLT 1 schema), but to no avail. The schema seems to have been parsed by Visual Studio, as I can hover my cursor over the namespace declaration in the stylesheet (xmlns:xsl="http://www.w3.org/1999/XSL/Transform") and see the comments from the new schema, however, intellisense still refers to the XSLT 1 implementation. For example the element has a warning that 'xsl:function is not yet available'. Do I need to register the schema in some way? Any suggestions welcome.

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  • Using the "naked" attribute for functions in GCC

    - by Art Spasky
    GCC documentation (http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html) states in 6.29 Declaring Attributes of Functions "naked Use this attribute on the ARM, AVR, IP2K, RX and SPU ports to indicate that the specified function does not need prologue/epilogue sequences generated by the compiler. It is up to the programmer to provide these sequences. The only statements that can be safely included in naked functions are asm statements that do not have operands. All other statements, including declarations of local variables, if statements, and so forth, should be avoided. Naked functions should be used to implement the body of an assembly function, while allowing the compiler to construct the requisite function declaration for the assembler." Can I safely call functions using C syntax from naked functions, or only by using asm?

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  • Global variable call working only first time

    - by Ruthy
    Hello, I defined a global variable that is called from other view and it is working first time but not following ones, it keeps with value from first call! Suppose that is a cocoa fundamental problem and variable is not properly defined according its need. Thanks for any idea to solve it. declaration: @interface TableArchiveAppDelegate : NSObject <UIAppDelegate> { NSString *varName; } @property (nonatomic, copy) NSString *varName; then related lines on .m file: @synthesize varName; -(void)test{ varName = textField.text; } and request from another view: - (void)viewDidLoad { TableArchiveAppDelegate *mainDelegate = (TableArchiveAppDelegate *)[[UIApplication sharedApplication] delegate]; name.text = mainDelegate.varName; [super viewDidLoad]; }

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  • What does the '&' operator do in C++?

    - by rascher
    n00b question. I am a C guy and I'm trying to understand some C++ code. I have the following function declaration: int foo(const string &myname) { cout << "called foo for: " << myname << endl; return 0; } How does the function signature differ from the equivalent C: int foo(const char *myname) Is there a difference between using string *myname vs string &myname? What is the difference between & in C++ and * in C to indicate pointers? Similarly: const string &GetMethodName() { ... } What is the & doing here? Is there some website that explains how & is used differently in C vs C++?

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  • What features of interpreted languages can a compiled one not have?

    - by sub
    Interpreted languages are usually more high-level and therefore have features as dynamic typing (including creating new variables dynamically without declaration), the infamous eval and many many other features that make a programmer's life easier - but why can't compiled languages have these as well? I don't mean languages like Java that run on a VM, but those that compile to binary like C(++). I'm not going to make a list now but if you are going to ask which features I mean, please look into what PHP, Python, Ruby etc. have to offer. Which common features of interpreted languages can't/don't/do exist in compiled languages? Why?

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  • Visual c++ opencv 2.1 contains()

    - by kaushalyjain
    how to check whether a given point is contained in a rectangle using the contains() function in Rect_ construct... Please give me the exact function and its parameters.Like when i type this Point b(2,2); Rect a(10,10,50,50); cout<< Rect_::contains(b); There is a compile error saying 1c:\users\kaushal\documents\visual studio 2008\projects\test1\test1.cpp(23) : error C2352: 'cv::Rect_<Tp::contains' : illegal call of non-static member function 1c:\opencv2.1\include\opencv\cxcore.hpp(385) : see declaration of 'cv::Rect<_Tp::contains'

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  • Difference between these two namespaces in javascript

    - by Lol coder
    First off, all I'm trying to do is to structure my javascript code properly. I've been told I must not have anything global. So I took the 2 types of namespaces declaration from this answer and now asking you guys for the pros and cons of each. var namespace1 = new function () { var internalFunction = function () { }; this.publicFunction = function () { }; }; var namespace2 = { publicFunction: function () { } }; Also, how do i have a private function in the last one namespace2?

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  • compare function for upper_bound / lower_bound

    - by Martin Beckett
    I want to find the first item in a sorted vector that has a field less than some value x. I need to supply a compare function that compares 'x' with the internal value in MyClass but I can't work out the function declaration. Can't I simply overload '<' but how do I do this when the args are '&MyClass' and 'float' ? float x; std::vector< MyClass >::iterator last = std::upper_bound(myClass.begin(),myClass.end(),x);

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  • How do I prevent my form from freezing when it is loading an image from the web at the click of a button?

    - by Vimal Basdeo
    I want to display an image from the web to a panel in another Jframe at the click of a button but whenever I click the button first the image loads and during this time the current form potentially freezes and once the image has loaded the form is displayed with the image.. How can I avoid the situation where my form freezes since it is very irritating My codes :: My current class private void btn_TrackbusActionPerformed(java.awt.event.ActionEvent evt) { try { sendMessage("Query,map,$,start,211,Arsenal,!"); System.out.println(receiveMessage()); } catch (UnknownHostException ex) { Logger.getLogger(client_Trackbus.class.getName()).log(Level.SEVERE, null, ex); } catch (IOException ex) { Logger.getLogger(client_Trackbus.class.getName()).log(Level.SEVERE, null, ex); } catch (Exception ex) { Logger.getLogger(client_Trackbus.class.getName()).log(Level.SEVERE, null, ex); } client_trackedbus nextform=new client_trackedbus(planform,connection,packet_receive,packet_send); this.setVisible(false); this.dispose(); nextform.setVisible(true); // TODO add your handling code here: } My next class that displays the image public class client_trackedbus extends javax.swing.JFrame { client_planform planform=null; DatagramSocket connection=null; DatagramPacket packet_receive=null; DatagramPacket packet_send=null; JLabel label=null; /** Creates new form client_trackedbus */ public client_trackedbus(client_planform planform,DatagramSocket connection,DatagramPacket packet_receive,DatagramPacket packet_send) { initComponents(); this.planform=planform; this.connection=connection; this.packet_receive=packet_receive; this.packet_send=packet_send; try { displayMap("http://www.huddletogether.com/projects/lightbox2/images/image-2.jpg", jPanel1, new JLabel()); } catch (MalformedURLException ex) { Logger.getLogger(client_trackedbus.class.getName()).log(Level.SEVERE, null, ex); } } private void displayMap(String url,JPanel panel,JLabel label) throws MalformedURLException{ URL imageurl=new URL(url); Image image=(Toolkit.getDefaultToolkit().createImage(imageurl)); ImageIcon icon = new ImageIcon(image); label.setIcon(icon); panel.add(label); // System.out.println(panel.getSize().width); this.getContentPane().add(panel); } /** This method is called from within the constructor to * initialize the form. * WARNING: Do NOT modify this code. The content of this method is * always regenerated by the Form Editor. */ @SuppressWarnings("unchecked") // <editor-fold defaultstate="collapsed" desc="Generated Code"> private void initComponents() { jPanel1 = new javax.swing.JPanel(); jLabel1 = new javax.swing.JLabel(); btn_Exit = new javax.swing.JButton(); btn_Plan = new javax.swing.JButton(); setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); setTitle("Public Transport Journey Planner"); javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1); jPanel1.setLayout(jPanel1Layout); jPanel1Layout.setHorizontalGroup( jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 368, Short.MAX_VALUE) ); jPanel1Layout.setVerticalGroup( jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 172, Short.MAX_VALUE) ); jLabel1.setFont(new java.awt.Font("Arial", 1, 18)); jLabel1.setText("Your tracked bus"); btn_Exit.setText("Exit"); btn_Exit.addActionListener(new java.awt.event.ActionListener() { public void actionPerformed(java.awt.event.ActionEvent evt) { btn_ExitActionPerformed(evt); } }); btn_Plan.setText("Plan journey"); btn_Plan.addActionListener(new java.awt.event.ActionListener() { public void actionPerformed(java.awt.event.ActionEvent evt) { btn_PlanActionPerformed(evt); } }); javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); getContentPane().setLayout(layout); layout.setHorizontalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGap(104, 104, 104) .addComponent(jLabel1)) .addGroup(layout.createSequentialGroup() .addContainerGap() .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)) .addGroup(layout.createSequentialGroup() .addGap(65, 65, 65) .addComponent(btn_Plan) .addGap(65, 65, 65) .addComponent(btn_Exit, javax.swing.GroupLayout.PREFERRED_SIZE, 87, javax.swing.GroupLayout.PREFERRED_SIZE))) .addContainerGap(20, Short.MAX_VALUE)) ); layout.setVerticalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGap(35, 35, 35) .addComponent(jLabel1) .addGap(18, 18, 18) .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) .addGap(18, 18, 18) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) .addComponent(btn_Exit) .addComponent(btn_Plan)) .addContainerGap(12, Short.MAX_VALUE)) ); pack(); }// </editor-fold> private void btn_ExitActionPerformed(java.awt.event.ActionEvent evt) { // TODO add your handling code here: Exitform(); } private void btn_PlanActionPerformed(java.awt.event.ActionEvent evt) { // TODO add your handling code here: this.setVisible(false); this.dispose(); this.planform.setVisible(true); } private void Exitform(){ this.setVisible(false); this.dispose(); } /** * @param args the command line arguments */ public static void main(String args[]) { java.awt.EventQueue.invokeLater(new Runnable() { public void run() { // new client_trackedbus().setVisible(true); } }); } // Variables declaration - do not modify private javax.swing.JButton btn_Exit; private javax.swing.JButton btn_Plan; private javax.swing.JLabel jLabel1; private javax.swing.JPanel jPanel1; // End of variables declaration }

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