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Search found 50304 results on 2013 pages for 'class variables'.

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  • Overriding vs Virtual

    - by anonymous
    What is the purpose of using the reserved word virtual in front of functions? If I want a child class to override a parent function, I just declare the same function such as "void draw(){}". class Parent{ public: void say(){ std::cout << "1"; }}; class Child : public Parent{public:void say(){ std::cout << "2"; } }; int main() { Child* a = new Child(); a->say(); return 0; } The output is 2. So again, why would the reserved word "virtual" be necessary in the header of say() ? Thanks a bunch.

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  • [c++] Resolving namespace conflicts

    - by Kyle
    I've got a namespace with a ton of symbols I use, but I want to overwrite one of them: external_library.h namespace lottaStuff { class LotsOfClasses {}; class OneMoreClass {}; }; my_file.h using namespace lottaStuff; namespace myCustomizations { class OneMoreClass {}; }; my_file.cpp using myCustomizations::OneMoreClass; int main() { OneMoreClass foo; // error: reference to 'OneMoreClass' is ambiguous return 0; } How do I get resolve the 'ambiguous' error without resorting to replacing 'using namespace lottaStuff' with a thousand individual "using xxx;" statements?

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  • Which is the best and appropriate way to write the code in Winforms ?

    - by Harikrishna
    What is the best way to write the code ? (1) Like directly writing the code in the button_click() event. or (2) Make the function of that code which I write in button_click() event and write this function in one class and then that function I should call in the button_Click() event.Like is it called three-tired approach to write the code ? Like in button_Click() event I write the code to save the records in csv file from datatable.So I should write that code in button_Click() event or I should make one new function and one new class and write that code in that function which is the new class and calling that function in button_Click() event. This is only one example but I am talking about all the code written in my application that which is the appropriate and best way to write the code and what are the benefits ? Note that I write the code in Winforms with c#.

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  • Objective C - Custom Getter with inheritance

    - by anhdat
    Recently I have worked with Core Data. When I want to set a default value for some fields, I came up with this problem: So I made a simple represent: We have 2 class Parent and Child, in which Child inherit from Parent. // Parent.h @interface Parent : NSObject @property (strong, nonatomic) NSString *lastName; // Child.h @interface Child : Parent In Parent class, I made a custom getter to set a default value when nothing is set: // Parent.h - (NSString *)lastName { if (_lastName) { return _lastName; } else { return @"Parent Default Name"; } } But I cannot make a custom default value for the field "name" which Child inherits from its Parent. // Child.h @implementation Child - (NSString *)lastname { if (super.lastName) { return super.lastName; } else { return @"Child Default Name"; } } Apparently, this method is never called. So my question here is: How can I set a custom getter for the field the Child class inherits from Parent without define an overriding property?

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  • Yahoo Astra flash component error BaseScrollPane not found

    - by Chris
    I'm trying to use the Astra library from Yahoo but I'm getting an error saying the base class BaseScrollPane is not found. It appears to be imported from fl.containers.BaseScrollPane, which leads me to believe it should be a part of the base flash 10 library and therefore should be available, but it appears to be missing. Is this part of a separate package from somewhere? Update: For what it's worth, I found the actual class files in the Configuration/Component Source folder on my hard drive, but adding that to the class path (as well as the Components directory) did no good. I ended up fixing the issue by dragging a scroll pane component to the stage from the Components window and then deleting it, but I'm not sure what exactly that action changed that made it work, and would like to know for future reference.

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  • ActiveRecord has_many and polymorphic

    - by leomayleomay
    I've came into a problem while working with AR and polymorphic, here's the description, class Base < ActiveRecord::Base; end class Subscription < Base set_table_name :subscriptions has_many :posts, :as => :subscriptable end class Post < ActiveRecord::Base belongs_to :subscriptable, :polymorphic => true end in the console, >> s = Subscription.create(:name => 'test') >> s.posts.create(:name => 'foo', :body => 'bar') and it created a Post like: #<Post id: 1, name: "foo", body: "bar", subscriptable_type: "Base", subscriptable_id: 1, created_at: "2010-05-10 12:30:10", updated_at: "2010-05-10 12:30:10"> the subscriptable_type is Base but Subscription, anybody can give me a hand on this?

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  • Remove a DIV using a link

    - by GSTAR
    HTML: <div class="row"> <!-- content --> <a href="#" class="remove">remove</a> </div> JS: $('.remove').click(function(){ $(this).parent().remove(); return false; }); If there is only one DIV it works OK but when there are multiple DIVS (class="row") it won't do anything. No errors are returned either. EDIT: I should add that by default there is only one div - additional divs get dynamically created using a jQuery clone function - perhaps this is why it won't recognise the new link/div?

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  • C#: Storting Instance of Objects in (Hashtable)

    - by DaGambit
    Hi I tried filling a Hashtable in the following way: ResearchCourse resCourse= new ResearchCourse();//Class Instance resCourse.CID="RC1000"; resCourse.CName="Rocket Science"; TaughtCourse tauCourse= new TaughtCourse();//Class Instance tauCourse.CID="TC1000"; tauCourse.CName="Marketing"; Hashtable catalog = new Hashtable(); catalog.Add("1", "resCourse.CID"); catalog.Add("2", "tauCourse.CID"); foreach (DictionaryEntry de in catalog) { Console.WriteLine("{0}, {1}", de.Key, de.Value); } Output Result to Console was: 1, resCourse.CID 2, tauCourse.CID Expected Result to be: 1, RC1000 2, TC2000 What am I misunderstanding about Hashtables? What is an easy way for the Hashtable to store the class instance and its values?

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  • placing image as div background

    - by Lucka
    How can I place only an image in a div as background image, and add url link to it. Currenty I'm doing it this way: <div class="image"><a href="example.com"><img src="books.png" alt="Test" /></a></div> I want to do something like following, but its not working (the image does not appear). <div class="image"><a href="example.com"><span class="books"></span></a></div> Thanks.

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  • php query cant figure out the problem

    - by Eat
    I dont get an error but it does not return me the row values as well. How can I address the problem? <?php //DATABASE $dbConn = mysql_connect($host,$username,$password); mysql_select_db($database,$dbConn); $SQL = mysql_query("SELECT N.*, C.CatID FROM News N INNER JOIN Categories C ON N.CatID = C.CatID WHERE N.Active = 1 ORDER BY DateEntered DESC"); while ( $Result = mysql_fetch_array($SQL) or die(mysql_error())) { $CatID[] = $Result[CatID]; $NewsName[] = $Result[NewsName]; $NewsShortDesc[] = $Result[NewsShortDesc]; } // mysql_free_result($Result); ?> <div class="toparticle"> <span class="section"><?=$CatID[0] ?> </span> <span class="headline"><?=$NewsName[0] ?></span> <p><?=$NewsShortDesc[0] ?></p> </div>

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  • What is dbReferenceProperty?

    - by user246114
    Hi, In the python app engine docs, I see something called dbReferenceProperty. I can't understand what it is, or how it's used. I'm using the java interface to app engine, so I'm not sure if there's an equivalent. I'm interested in it because it sounds like some sort of pseudo-join, where we can point a property of a class to some other object's value - something like if we had: class User { private String mPhotoUrl; private String mPhone; private String mState; private String mCountry; .. etc .. } class UserLite { @ReferenceProperty User.mPhotoUrl; private String mPhotoUrl; } then if we had to update a User object's mPhotoUrl value, the change would somehow propagate out to all UserLite instances referencing it, rather than having to update every UserLite object instance manually, Thanks

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  • css: top and bottom with flexible centre

    - by Haroldo
    is it possible with just css2 to have the following: 3 divs: <div id="wrap_centre"> <div class="top"></div> <div class="mid"></div> <div class="bot"></div> </div> all the content to be in the flexible div.mid section overlap the top and bottom parts not fussed about ie6 here's the photoshop with centre slice: as you can see the top and bottom parts are quite large and i need to overlap them from the middle slice...

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  • Java how to load modules

    - by gerardorn
    heres my problem: im building a server that loads modules. each module is a .jar file. inside the jar theres all the classes that the module need. the server needs to read the jar, find the main class (it doesnt have the main method on it is just the class that makes the module work but not as a different program), build an object of that class and store it in a vector of modules so that it can acces to a specific module depending on the job to be done. how can i do that? as far as the server, it is listening and reciving request, but thes no modules to delegate the job to, since my vector of modules is empty

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  • Prototype - DOM Traversal with up()

    - by Jason McCreary
    I have the following structure: <form> <div class="content"> ... </div> <div class="action"> <p>Select <a class="select_all" href="?select=1" title="Select All">All</a></p> </div> </form> I am using Prototype's up() to traverse the DOM in order to find the <form> element in respect to the a.select_all. However the following doesn't work: select_link.up('form'); // returns undefined Yet, this does. select_link.up().up().up(); // returns HTMLFormElement Clearly this is an ancestor of a.select_all. The API Docs state Element.up() supports a CSSRule. What am I missing here?

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  • Is it possible to create an enum whose instance can't be created but can be used for readonly purpos

    - by Shantanu Gupta
    I created an enum where I stored some table names. I want it to be used to get the name of the table like ds.Tables[BGuestInfo.TableName.L_GUEST_TYPE.ToString()]. public class a { public enum TableName : byte { L_GUEST_TYPE = 0 ,L_AGE_GROUP = 1 ,M_COMPANY = 2 ,L_COUNTRY = 3 ,L_EYE_COLOR = 4 ,L_GENDER = 5 ,L_HAIR_COLOR = 6 ,L_STATE_PROVINCE = 7 ,L_STATUS = 8 ,L_TITLE = 9 ,M_TOWER = 10 ,L_CITY = 11 ,L_REGISTER_TYPE = 12 } } class b { a.TableName x; //trying to restrict this ds.Tables[a.TableName.L_GUEST_TYPE] //accessible and can be used like this } This is my enum. Now I have not created any instance of this enum so that no one can use it for other than read only purpose. For this enum to be accessible in outer classes as well I have to make it public which means some outer class can create its object as well. So what can i do so as to restrict its instance creation.

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  • Is there anything wrong with taking immediate actions in constructors?

    - by pestaa
    I have classes like this one: class SomeObject { public function __construct($param1, $param2) { $this->process($param1, $param2); } ... } So I can instantly "call" it as some sort of global function just like new SomeObject($arg1, $arg2); which has the benefits of staying concise, being easy to understand, but might break unwritten rules of semantics by not waiting till a method is called. Should I continue to feel bad because of a bad practice, or there's really nothing to worry about? Clarification: I do want an instance of the class. I do use internal methods of the class only. I initialize the object in the constructor, but call the "important" action-taker methods too. I am selfish in the light of these sentences.

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  • Disabled button working in my View page using jquery

    - by kumar
    <% using (Html.BeginForm("Student", "Home", FormMethod.Post, new { @id = "exc-"})) { %> this is my Beginform and I have buttons in my view.. <fieldset> <div> <input id="btnSelectAll" type="button" class="button" value="Select All" /> <input id="btnSubmit" type="submit" class="button" value="Save" /> <input id="btnCancel" type="button" class="button" value="Cancel" /> </div> </fieldset> On document load I am doing disabling my submit button $('#btnSubmit').attr('disabled','disabled'); $('#btnCancel').attr('disabled','disabled'); I am seeing My buttons are Disabled but when I click on Save button still its going to my controler? please can anybody tell me why its doing like this?

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  • where to put business logic in a library?

    - by fayer
    i'm going to create a library that consists of a lot of separate classes. i'm very familiar with mvc but have never created a pure library before. i wonder where i should put the business logic? the logic that is in the controller in a mvc. should it be in a class? or in a "bootstrap" file? and should one file include every class, or should only one class include its classes it uses? thanks!

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  • @ExceptionHandler doesn't handle the thrown exceptions

    - by Javi
    Hello, I have a method in my controller which will handle the exceptions thrown by the application. So I have a method like this one. @Controller public class ExceptionController { @RequestMapping(value="/error") @ExceptionHandler(value={Exception.class, NullPointerException.class}) public String showError(Exception e, Model model){ return "tiles:error"; } } And to try I if it works I throw a NullPointerException in another method in other method controller: boolean a = true; if(a){ throw new NullPointerException(); } After the exception is thrown it is printed in the JSP, but it doesn't go throw my showError() method (I've set a breakpoint there and it never enters). showError() method will catch the exception and will show different error pages depending on the exception type (though now it always shows the same error page). If I go to the url /error it shows the error page so the showError() method is OK. I'm using Spring 3. What can be the problem? Thanks.

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  • Where do you hang your semantic information, html?

    - by bobobobo
    Well, I keep putting semantic information about what an element means for the page logically in the class attribute <li class="phone-number">555-5555</li> It seems to work for this dual purpose of hanging semantic information and a pointer to how to style it. I'm not sure if this is the best idea, I'm trying to see if others have other ways of doing it. I also started to use a hidden input: <li>555-5555 <input class="semantics" type="hidden" value="phone-number" /></li> inside an element, so with jQuery, I can retrieve additional information about the element using li.find( '.semantics' ).val() To get an element's semantics from JavaScript

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  • Delphi : What is the best way for passing data between forms?

    - by Flom Enol
    It may seem a little newbie, but I really have got problem with it. I have a form (not the main one)for getting many different data form the user and I want to pass it to a manager class for creating an object with these. The problem is that I can't have this class to use the other unit (getting circle uses) and also it doesn't have access to the manager class instance (which is in main form). So, what shall I do? I've already considered using public variable but I have a bad feeling about it (regarding OOD patterns). Any ideas? thanks in advance.

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  • Could someone tell me if my C++ indent style is named? (example given)

    - by Maulrus
    I'm learning C++. For me, my programming style is just what looks the best; it doesn't seem to follow the rules of any one particular style. Here's an example void f(int x){ //no space between close-paren and bracket if (!x){ cout << "x is non-zero\n"; } //closing bracket indented to the same level as the original statement } It's only slightly different for something like a class or a namespace: class myClass {}; //space between class name and bracket, otherwise the same as functions K&R style does uses that kind of bracketing for statements, but my style uses it for everything. I'd like to know if there's a name for it so I can say simply what my indent style is without having to explain using examples like these.

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  • How do you extend a Ruby module with macro-like metaprogramming methods?

    - by Ian Terrell
    Consider the following extension (the pattern popularized by several Rails plugins over the years): module Extension def self.included(recipient) recipient.extend ClassMethods recipient.class_eval { include InstanceMethods } end module ClassMethods def macro_method puts "Called macro_method within #{self.name}" end end module InstanceMethods def instance_method puts "Called instance_method within #{self.object_id}" end end end If you wished to expose this to every class, you can do the following: Object.send :include, Extension Now you can define any class and use the macro method: class FooClass macro_method end #=> Called macro_method within FooClass And instances can use the instance methods: FooClass.new.instance_method #=> Called instance_method within 2148182320 But even though Module.is_a?(Object), you cannot use the macro method in a module: module FooModule macro_method end #=> undefined local variable or method `macro_method' for FooModule:Module (NameError) This is true even if you explicitly include the original Extension into Module with Module.send(:include, Extension). How do you add macro like methods to Ruby modules?

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  • Reference to an instance method of a particular object

    - by Andrey
    In the following code, if i try to pass method reference using the class name, works. But passing the reference variable compiler gives an error, i do not understand why? public class User { private String name; public User(String name) { this.name = name; } public void printName() { System.out.println(name); } } public class Main { public static void main(String[] args) { User u1 = new User("AAA"); User u2 = new User("BBB"); User u3 = new User("ZZZ"); List<User> userList = Arrays.asList(u1, u2, u3); userList.forEach(User::printName); // works userList.forEach(u1::printName); // compile error } } Thanks,

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  • Javascript Inheritance and Arrays

    - by Inespe
    Hi all! I am trying to define a javascript class with an array property, and its subclass. The problem is that all instances of the subclass somehow "share" the array property: // class Test function Test() { this.array = []; this.number = 0; } Test.prototype.push = function() { this.array.push('hello'); this.number = 100; } // class Test2 : Test function Test2() { } Test2.prototype = new Test(); var a = new Test2(); a.push(); // push 'hello' into a.array var b = new Test2(); alert(b.number); // b.number is 0 - that's OK alert(b.array); // but b.array is containing 'hello' instead of being empty. why? As you can see I don't have this problem with primitive data types... Any suggestions?

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