Search Results

Search found 9718 results on 389 pages for 'classes'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 43/389 | < Previous Page | 39 40 41 42 43 44 45 46 47 48 49 50  | Next Page >

  • How do I change the class of an object to a subclass of its current class in C++?

    - by Jared P
    I have an array of pointers to a base class, so that I can make those pointers point to (different) subclasses of the base class, but still interact with them. (really only a couple of methods which I made virtual and overloaded) I'm wondering if I can avoid using the pointers, and instead just make an array of the base class, but have some way to set the class to the subclass of my choosing. I know there must be something there specifying the class, as it needs to use that to look up the function pointer for virtual methods. By the way, the subclasses all have the same ivars and layout. Note: the design is actually based on using a template argument instead of a variable, due to performance increases, so really the abstract base class is just the interface for the subclasses, which are all the same except for their compiled code. Thanks

    Read the article

  • printing the instance in Python

    - by kame
    Hello! With this code: class Complex: def __init__(self, realpart, imagpart): self.real = realpart self.imag = imagpart print self.real, self.imag class Circle: def __init__(self, radius): print "A circle wiht the radius", radius, "has the properties:" print "circumference =", 3.14*radius print "area =", 3.14*radius**2 I get this output: >>> Complex(3,2) 3 2 <__main__.Complex instance at 0x01412210> But why does he print the last line?

    Read the article

  • [Android] Putting Serializable Classes into SQL?

    - by CaseyB
    Here's the situation. I have a bunch of objects that implement Serializable that I want to store in a SQL database. I have two questions Is there a way to serialize the object directly into the database Is that the best way to do it or should I Write the object out to a formatting String and put it in the database that way and then parse it back out Write each member to the database with a field that is unique to each object

    Read the article

  • Automatically Add a Prefix to Column Names for @Embeddable Classes

    - by VeeArr
    I am developing a project in which I am persisting some POJOs by adding Hibernate annotations. One problem I am running into is that code like this fails, as Hibernate tries to map the sub-fields within the Time_T onto the same column (i.e. startTime.sec and stopTime.sec both try to map to the colum sec, causing an error). @Entity public class ExampleClass { @Id long eventId; Time_T startTime; Time_T stopTime; } @Embeddable public class Time_T { int sec; int nsec; } As there will be many occurrences like this throughout the system, it would be nice if there was an option to automatically append a prefix to the column name (e.g. make the columns be startTime_sec, startTime_nsec, stopTime_sec, stopTime_nsec), without having to apply overrides on a per-field basis. Does Hibernate have this capability, or is there any other reasonable work-around?

    Read the article

  • Nested Dynamic PHP Class

    - by user338844
    Alright, I may just need a terminology update, but I have been playing in Magento and Joomla, and they do references like $mage = new Mage; $mage->block('blockname'); where class Mage through some process I am failing to figure out is calling: class blockname extends something{ } Don't quote me on that code, however I am looking to do something like that where I have a file that I can do $myscript-block('blockname'); and it will load and call the file with class blockname. I hope that is not too confusing, but any help is appreciated. Thanks in advance!

    Read the article

  • java - find out the type of class which implements of other classes

    - by Johnzzz
    i have a kind of specific problem, let's say, that i have public interface A { } //------------------------------ public class B implements A{ static int countx = 0; } //---------------------------------- public class C implements A{ static int county = 0; } //---------------------------------- public class Arc { public A from; public A to; //======================================== and now I have an object a (which is an instance of Arc) and I want to find out whether it is an instance of B or C and get to the atributes countX or countY (stg like a.from.countX) any ideas? :)

    Read the article

  • Confusion over C++ new operator and classes

    - by Nils
    Hi all I created a simple class in C++ which has a private dynamic array. In the constructor I initialize the array using new and in the destructor I free it using delete. When I instantiate the class using Class a = Class(..); it works as expected, however it seems I cannot instantiate it using the new operator (Like Class *a = new Class(..);), I always get a segmentation fault. What I don't understand is when I should use new to instantiate a class and when just call the constructor or should it be possible to instantiate a class either with new or by just calling the constructor. float** A = new float*[3]; for (int i=0; i<3; i++) { A[i] = new float[3]; } A[0][0] = 3; A[0][1] = 3; A[0][2] = 4; A[1][0] = 5; A[1][1] = 6; A[1][2] = 7; A[2][0] = 1; A[2][1] = 2; A[2][2] = 3; Matrix *M = new Matrix(A, 3, 3); delete[] A; delete M; Below the class definition.. class Matrix { private: int width; int height; int stride; float* elements; public: Matrix(float** a, int n, int m); ~Matrix(); }; Matrix::Matrix(float** a, int n, int m) { // n: num rows // m: elem per rows elements = new float[n*m]; for (int i=0; i<n; i++) { for (int j=0; j<m; j++) { elements[i*n + j] = a[n][m]; } } } Matrix::~Matrix() { delete[] elements; }

    Read the article

  • Adding variably named fields to Python classes

    - by Carson Myers
    I have a python class, and I need to add an arbitrary number of arbitrarily long lists to it. The names of the lists I need to add are also arbitrary. For example, in PHP, I would do this: class MyClass { } $c = new MyClass(); $n = "hello" $c.$n = array(1, 2, 3); How do I do this in Python? I'm also wondering if this is a reasonable thing to do. The alternative would be to create a dict of lists in the class, but since the number and size of the lists is arbitrary, I was worried there might be a performance hit from this. If you are wondering what I'm trying to accomplish, I'm writing a super-lightweight script interpreter. The interpreter walks through a human-written list and creates some kind of byte-code. The byte-code of each function will be stored as a list named after the function in an "app" class. I'm curious to hear any other suggestions on how to do this as well.

    Read the article

  • Javascript methods, classes and events

    - by Randy Gurment
    Hi, how should I document this piece of code: // Is this class? colors = { // Is this method? "red" : function() { // Do something... } // Still method? "black" : { // So what is this? "black-1" : function() { /* Do something */ } } } I am using YUI Doc. These tags are available @module @class @method @event @property

    Read the article

  • Operator as and generic classes

    - by abatishchev
    I'm writing .NET On-the-Fly compiler for CLR scripting and want execution method make generic acceptable: object Execute() { return type.InvokeMember(..); } T Execute<T>() { return Execute() as T; /* doesn't work: The type parameter 'T' cannot be used with the 'as' operator because it does not have a class type constraint nor a 'class' constraint */ // also neither typeof(T) not T.GetType(), so on are possible return (T) Execute(); // ok } But I think operator as will be very useful: if result type isn't T method will return null, instead of an exception! Is it possible to do?

    Read the article

  • C# Inconsistent Accessibility (Multiple Classes)

    - by MattP
    I am getting an Inconsistent Accessibility problem where I have one class that contains a List of another class namespace NS { public class Foo { public Foo() { this.bar = new List<Bar>(); } private List<Bar> bar; } public class Bar { public Bar() { } } } The error is property type NS.Bar is less accessible than property NS.Foo.Bar The structure to the application is each Foo consists of a Dynamic Array (List) of Bar. It's not ecommerce but the best example would be an eCommerce Store-Categories-Products in terms of how the data will be accessed.

    Read the article

  • SwingWorker exceptions lost even when using wrapper classes

    - by Ti Strga
    I've been struggling with the usability problem of SwingWorker eating any exceptions thrown in the background task, for example, described on this SO thread. That thread gives a nice description of the problem, but doesn't discuss recovering the original exception. The applet I've been handed needs to propagate the exception upwards. But I haven't been able to even catch it. I'm using the SimpleSwingWorker wrapper class from this blog entry specifically to try and address this issue. It's a fairly small class but I'll repost it at the end here just for reference. The calling code looks broadly like try { // lots of code here to prepare data, finishing with SpecialDataHelper helper = new SpecialDataHelper(...stuff...); helper.execute(); } catch (Throwable e) { // used "Throwable" here in desperation to try and get // anything at all to match, including unchecked exceptions // // no luck, this code is never ever used :-( } The wrappers: class SpecialDataHelper extends SimpleSwingWorker { public SpecialDataHelper (SpecialData sd) { this.stuff = etc etc etc; } public Void doInBackground() throws Exception { OurCodeThatThrowsACheckedException(this.stuff); return null; } protected void done() { // called only when successful // never reached if there's an error } } The feature of SimpleSwingWorker is that the actual SwingWorker's done()/get() methods are automatically called. This, in theory, rethrows any exceptions that happened in the background. In practice, nothing is ever caught, and I don't even know why. The SimpleSwingWorker class, for reference, and with nothing elided for brevity: import java.util.concurrent.ExecutionException; import javax.swing.SwingWorker; /** * A drop-in replacement for SwingWorker<Void,Void> but will not silently * swallow exceptions during background execution. * * Taken from http://jonathangiles.net/blog/?p=341 with thanks. */ public abstract class SimpleSwingWorker { private final SwingWorker<Void,Void> worker = new SwingWorker<Void,Void>() { @Override protected Void doInBackground() throws Exception { SimpleSwingWorker.this.doInBackground(); return null; } @Override protected void done() { // Exceptions are lost unless get() is called on the // originating thread. We do so here. try { get(); } catch (final InterruptedException ex) { throw new RuntimeException(ex); } catch (final ExecutionException ex) { throw new RuntimeException(ex.getCause()); } SimpleSwingWorker.this.done(); } }; public SimpleSwingWorker() {} protected abstract Void doInBackground() throws Exception; protected abstract void done(); public void execute() { worker.execute(); } }

    Read the article

  • Problem about C++ class (inheritance, variables scope and functions)

    - by Luigi Giaccari
    I have a class that contains some data: class DATA Now I would to create some functions that uses those data. I can do it easily by writing member functions like DATA::usedata(); Since there are hundreds of functions, I would to keep an order in my code, so I would like to have some "categories" (not sure of the correct name) like: DATA data; data.memory.free(); data.memory.allocate(); data.file.import(); data.whatever.foo(); where memory, file and whatever are the "categories" and free, allocate and foo are the functions. I tried the inheritance way, but I got lost since I can not declare inside DATA a memory or file object, error C2079 occurs: http://msdn.microsoft.com/en-us/library/9ekhdcxs%28VS.80%29.aspx Since I am not a programmer please don't be too complicated and if you have an easier way I am all ears.

    Read the article

  • PHP classes, parse syntax errors when using 'var' to declare variables

    - by jon
    I am a C# guy trying to translate some of my OOP understanding over to php. I'm trying to make my first class object, and are hitting a few hitches. Here is the beginning of the class: <?php require("Database/UserDB.php"); class User { private var $uid; private var $username; private var $password; private var $realname; private var $email; private var $address; private var $phone; private var $projectArray; public function _construct($username) { $userArray = UserDB::GetUserArray($username); $uid = $userArray['uid']; $username = $userArray['username']; $realname = $userArray['realname']; $email = $userArray['email']; $phone = $userArray['phone']; $i = 1; $projectArray = UserDB::GetUserProjects($this->GetID()); while($projectArray[$i] != null) { $projectArray[$i] = new Project($projectArray[$i]); } UserDB.php is where I have all my static functions interacting with the Database for this User Class. I am getting errors using when I use var, and I'm getting confused. I know I don't HAVE to use var, or declare the variables at all, but I feel it is a better practice to do so. the error is "unexpected T_VAR, expecting T_VARIABLE" When I simply remove var from the declarations it works. Why is this?

    Read the article

  • Using classes for the first time,help in debugging

    - by kaushik
    here is post my code:this is no the entire code but enough to explain my doubt.please discard any code line which u find irrelavent enter code here saving_tree={} isLeaf=False class tree: global saving_tree rootNode=None lispTree=None def __init__(self,x): file=x string=file.readlines() #print string self.lispTree=S_expression(string) self.rootNode=BinaryDecisionNode(0,'Root',self.lispTree) class BinaryDecisionNode: global saving_tree def __init__(self,ind,name,lispTree,parent=None): self.parent=parent nodes=lispTree.getNodes(ind) print nodes self.isLeaf=(nodes[0]==1) nodes=nodes[1]#Nodes are stored self.name=name self.children=[] if self.isLeaf: #Leaf Node print nodes #Set the leaf data self.attribute=nodes print "LeafNode is ",nodes else: #Set the question self.attribute=lispTree.getString(nodes[0]) self.attribute=self.attribute.split() print "Question: ",self.attribute,self.name tree={} tree={str(self.name):self.attribute} saving_tree=tree #Add the children for i in range(1,len(nodes)):#Since node 0 is a question # print "Adding child ",nodes[i]," who has ",len(nodes)-1," siblings" self.children.append(BinaryDecisionNode(nodes[i],self.name+str(i),lispTree,self)) print saving_tree i wanted to save some data in saving_tree{},which i have declared previously and want to use that saving tree in the another function outside the class.when i asked to print saving_tree it printing but,only for that instance.i want the saving_tree{} to have the data to store data of all instance and access it outside. when i asked for print saving_tree outside the class it prints empty{}.. please tell me the required modification to get my required output and use saving_tree{} outside the class..

    Read the article

  • c++ design question: Can i query the base classes to find the number of derived classes satisfying a

    - by vivekeviv
    I have a piece of code like this class Base { public: Base(bool _active) { active = _active; } void Configure(); void Set Active(bool _active); private: bool active; }; class Derived1 : public Base { public: Derived1(bool active):Base(active){} }; similarly Derived 2 and Derived 3 Now if i call derived1Object.Configure, i need to check how many of the derived1Obj, derived2Obj,derived3Obj is active. Should i add this in the "Base" class like a function say, GetNumberOfActive()? And If the implementation is like this: class Imp { public: void Configure() { //Code instantiating a particular Derived1/2/3 Object int GetNumberOfActiveDerivedObj(); baseRef.Configure(int numberOfActiveDerivedClasses); } prive: Derived1 dObj1(true); Derived2 dObj2(false); Derived3 dObj3(true); }; should i calculate the numberOfActive Derived Objects in Imp Class? THanks

    Read the article

  • What happens when you create an instance of an object containing no state in C#?

    - by liquorice
    I am I think ok at algorithmic programming, if that is the right term? I used to play with turbo pascal and 8086 assembly language back in the 1980s as a hobby. But only very small projects and I haven't really done any programming in the 20ish years since then. So I am struggling for understanding like a drowning swimmer. So maybe this is a very niave question or I'm just making no sense at all, but say I have an object kind of like this: class Something : IDoer { void Do(ISomethingElse x) { x.DoWhatEverYouWant(42); } } And then I do var Thing1 = new Something(); var Thing2 = new Something(); Thing1.Do(blah); Thing2.Do(blah); does Thing1 = Thing2? does "new Something()" create anything? Or is it not much different different from having a static class, except I can pass it around and swap it out etc. Is the "Do" procedure in the same location in memory for both the Thing1(blah) and Thing2(blah) objects? I mean when executing it, does it mean there are two Something.Do procedures or just one?

    Read the article

  • generate php classes in bash

    - by Derek
    i have this script: #!/bin/bash if [[ -z "$1" ]] ; then echo "Class is required" exit 1; fi if [[ -z "$2" ]] ; then package="Default" else package=$2; fi echo "<?php /** * $1.class.php * * Vcard class file. * @name Project * @author Author * @link http://www.domain.com * @copyright Copyright © 2011 * @package $package * @version 1.0 */ /** * The main $1 class * @package $package */ class $1 { /** * Constructor setup. */ public function __construct() { } /** * Destructor setup. */ public function __destruct() { } } " > $1.class.php php -l $1.class.php echo "Done"; if i do: ./generate.sh my_class it creates everything with my_class. how can i modify this to: MyClass? i need to use MyClass for the filename, and the class name etc... later in the code i use the argument (in this case my_class) for some other purposes. thanks

    Read the article

  • How are classes more secure than structures ?

    - by Asad Hanif
    Structure's member are public by default ans class's members are private by default. We can access private data members through a proper channel (using member function). If we have access to member functions we can read/write data in private data member, so how it is secure...we are accessing it and we are changing data too.....

    Read the article

  • Ruby on Rails: Modules vs. Classes

    - by Jack
    I'm trying to add a function that will be accessible throughout all parts of my program. I want something like: def GlobalFunctions.my_function(x,y) puts x + y end to be accessible for all models. Specifically I am trying to use a function like this in my seeds.rb file but I am most likely going to be reusing the code and don't want any redundancy. Now I know I can make a simple class, but I could also make a module. What are some reasons to go in either direction? And once I've decided on which type to use, how do I make it accessible throughout the whole program? I have tried a module, but I keep getting " Expected app/[module file] to define [ModuleName]"

    Read the article

  • Obj-C Sending Messages Between Classes

    - by user544359
    I'm a newbie in iPhone Programming. I'm trying to send a message from one view controller to another. The idea is that viewControllerA takes information from the user and sends it to viewControllerB. viewControllerB is then supposed to display the information in a label. viewControllerA.h #import <UIKit/UIKit.h> @interface viewControllerA : UIViewController { int num; } -(IBAction)do; @end viewControllerA.m #import "viewControllerA.h" #import "viewControllerB.h" @implementation viewControllerA - (IBAction)do { //initializing int for example num = 2; viewControllerB *viewB = [[viewControllerB alloc] init]; [viewB display:num]; [viewB release]; //viewA is presented as a ModalViewController, so it dismisses itself to return to the //original view, i know it is not efficient [self dismissModalViewControllerAnimated:YES]; } - (void)dealloc { [super dealloc]; } @end viewControllerB.h #import <UIKit/UIKit.h> @interface viewControllerB : UIViewController { IBOutlet UILabel *label; } - (IBAction)openA; - (void)display:(NSInteger)myNum; @end viewControllerB.m #import "viewControllerB.h" #import "viewControllerA.h" @implementation viewControllerB - (IBAction)openA { //presents viewControllerA when a button is pressed viewControllerA *viewA = [[viewControllerA alloc] init]; [self presentModalViewController:viewA animated:YES]; } - (void)display:(NSInteger)myNum { NSLog(@"YES"); [label setText:[NSString stringWithFormat:@"%d", myNum]]; } @end YES is logged successfully, but the label's text does not change. I have made sure that all of my connections in Interface Builder are correct, in fact there are other (IBAction) methods in my program that change the text of this very label, and all of those other methods work perfectly... Any ideas, guys? You don't need to give me a full solution, any bits of information will help. Thanks.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 39 40 41 42 43 44 45 46 47 48 49 50  | Next Page >