Search Results

Search found 8115 results on 325 pages for 'dynamic inheritance'.

Page 59/325 | < Previous Page | 55 56 57 58 59 60 61 62 63 64 65 66  | Next Page >

  • Why `is_base_of` works with private inheritance?

    - by Alexey Malistov
    Why the following code works? typedef char (&yes)[1]; typedef char (&no)[2]; template <typename B, typename D> struct Host { operator B*() const; operator D*(); }; template <typename B, typename D> struct is_base_of { template <typename T> static yes check(D*, T); static no check(B*, int); static const bool value = sizeof(check(Host<B,D>(), int())) == sizeof(yes); }; //Test sample class B {}; class D : private B {}; //Exspression is true. int test[is_base_of<B,D>::value && !is_base_of<D,B>::value]; Note that B is private base. Note that operator B*() is const. How does this work? Why this works? Why static yes check(D*, T); is better than static yes check(B*, int); ?

    Read the article

  • CSS LESS class inheritance

    - by Haradzieniec
    Here is a css description of properties for my #myform1 .btn1 class: #myform1 .btn1 { ... } #myform1 .btn1:hover { ... } #myform1 .btn1.active { ... } #myform1 .btn1.disabled { ... } Is it possible to add absolutely the same properties for my #myform2 .btn2 class using LESS (any way is OK) without writing #myform1 .btn1 ,#myform2 .btn2 { ... } #myform1 .btn1:hover, #myform2 .btn2:hover { ... } #myform1 .btn1.active, #myform2 .btn2.active { ... } #myform1 .btn1.disabled, #myform2 .btn2.disabled { ... } Is it possible?

    Read the article

  • Inheritance - initialization problem

    - by dumbquestion
    I have a c++ class derived from a base class in a framework. The derived class doesn't have any data members because I need it to be freely convertible into a base class and back - the framework is responsible for loading and saving the objects and I can't change it. My derived class just has functions for accessing the data. But there are a couple of places where I need to store some temporary local variables to speed up access to data in the base class. mydata* MyClass::getData() { if ( !m_mydata ) { // set to NULL in the constructor m_mydata = some_long_and complex_operation_to_get_the_data_in_the_base() } return m_mydata; } The problem is if I just access the object by casting the base class pointer returned from the framework to MyClass* the ctor for MyClass is never called and m_mydata is junk. Is there a way of only initializing the m_mydata pointer once?

    Read the article

  • Adding an inheritance to an Qt designed object

    - by Jaguar
    Hello, I have a problem and I want to implement the MVC pattern to my QT application, that's why I need for example to inherite in my QTableWidget about another class like myClass { myMethod(); } but our QTableWidget is contained by our Mainwidows that is designed by the QT designer and generate an ui_MainWindow class ! Do you know how to do that ? Is that a method inside the Qt Designer to do that ? or another method ? Thank you for your answer !

    Read the article

  • dynamic inheritance without touching classes

    - by Jasper
    I feel like the answer to this question is really simple, but I really am having trouble finding it. So here goes: Suppose you have the following classes: class Base; class Child : public Base; class Displayer { public: Displayer(Base* element); Displayer(Child* element); } Additionally, I have a Base* object which might point to either an instance of the class Base or an instance of the class Child. Now I want to create a Displayer based on the element pointed to by object, however, I want to pick the right version of the constructor. As I currently have it, this would accomplish just that (I am being a bit fuzzy with my C++ here, but I think this the clearest way) object->createDisplayer(); virtual void Base::createDisplayer() { new Displayer(this); } virtual void Child::createDisplayer() { new Displayer(this); } This works, however, there is a problem with this: Base and Child are part of the application system, while Displayer is part of the GUI system. I want to build the GUI system independently of the Application system, so that it is easy to replace the GUI. This means that Base and Child should not know about Displayer. However, I do not know how I can achieve this without letting the Application classes know about the GUI. Am I missing something very obvious or am I trying something that is not possible?

    Read the article

  • JavaScript inheritance extend function

    - by Zach
    I'm having some trouble understanding the IF clause at the end of this function from Pro JavaScript Design Patterns: function extend(subClass, superClass) { var F = function() {}; F.prototype = superClass.prototype; subClass.prototype = new F(); subClass.prototype.constructor = subClass; subClass.superclass = superClass.prototype; if(superClass.prototype.constructor == Object.prototype.constructor) { superClass.prototype.constructor = superClass; } } The book explains that these lines ensure that the superclass's constructor attribute is correctly set, even if the superclass is the Object class itself. Yet, if I omit those three lines and do the following: function SubClass() {}; extend(SubClass, Object); alert(Object.prototype.constructor == Object); The alert says 'true', which means the superclass's constructor is set correctly even without those last three lines. Under what conditions, then, does this IF statement do something useful? Thanks.

    Read the article

  • C# Property inheritance question

    - by mcxiand
    Hi all, How do i inherit a property in c# from an interface and give that property other name on the class? For example: public interface IFoo { int Num {get;set;} } public class IFooCls : IFoo { int Ifoo.Num{get;set} } In this case, what the property name in the interface is also the same in the class. What i want is to give other property name on the class but still pointing to "Num" in the interface in this case. In VB, we can do it like this: Public ReadOnly Property UserId() As String Implements System.Security.Principal.IIdentity.Name Get Return _userId End Get End Property

    Read the article

  • Inheritance and Implicit Type Casting

    - by Josué Molina
    Suppose I have the following three classes: class Animal {}; class Human : public Animal {}; class Dog : public Animal { public: void setOwner(Animal* owner) { this->owner = owner; } private: Animal* owner; }; Why is the following allowed, and what exactly is happening? Dog d; Human h; d.setOwner(&h); // ? At first, I tried to cast it like this d.setOwner(&(Animal)h), but the compiler gave me a warning, and I hit a run-time error. Edit: the warning the compiler gave me was "taking address of temporary". Why is this so?

    Read the article

  • multiple inheritance

    - by hitech
    when we say "a member declated as protected is accessible to any class imediately derived from it" what does this mean. in the follwing example get_number function can be accessible by the result class , as per the statement it sould only be accessile to test class. class student { protected: int roll_number; public: void get_number(int){ cout<< "hello"; } void put_number(void) {cout<< "hello"; } }; class test : public student { protected : float sub1; float sub2; public: void get_marks(float, float) {cout<< "hello"; roll_number = 10; } void put_marks(void) {cout<< "hello"; cout << "roll_number = " << roll_number ; } }; class result :public test { float total; public: void display(){cout<< "hello"; roll_number = 10; } }; int main() { result student; student.get_marks(2.2, 2.2); student.put_marks(); return 0; } i changed the code as per the first statement the protected variable roll_number not be accessible upto the result class ?

    Read the article

  • Not sure I am using inheritance/polymorphism issue?

    - by planker1010
    So for this assignment I have to create a car class(parent) and a certifiedpreowned (child) and I need to have the parent class have a method to check if it is still under warranty. *checkWarrantyStatus(). that method calls the boolean isCoveredUnderWarranty() to veryify if the car still has warranty. My issue is in the certifiedpreowned class I have to call the isCoveredUnderWarranty() as well to see if it is covered under the extended warranty and then have it be called via the checkWarrantyStatus() in the car method. I hope this makes sense. So to sum it up I need to in the child class have it check the isCoveredUnderWarranty with extended warranty info. Then it has to move to the parent class so it can be called via checkWarrantyStatus. Here is my code, I have 1 error. public class Car { public int year; public String make; public String model; public int currentMiles; public int warrantyMiles; public int warrantyYears; int currentYear =java.util.Calendar.getInstance().get(java.util.Calendar.YEAR); /** construct car object with specific parameters*/ public Car (int y, String m, String mod, int mi){ this.year = y; this.make = m; this.model = mod; this.currentMiles = mi; } public int getWarrantyMiles() { return warrantyMiles; } public void setWarrantyMiles(int warrantyMiles) { this.warrantyMiles = warrantyMiles; } public int getWarrantyYears() { return warrantyYears; } public void setWarrantyYears(int warrantyYears) { this.warrantyYears = warrantyYears; } public boolean isCoveredUnderWarranty(){ if (currentMiles < warrantyMiles){ if (currentYear < (year+ warrantyYears)) return true; } return false; } public void checkWarrantyStatus(){ if (isCoveredUnderWarranty()){ System.out.println("Your car " + year+ " " + make+ " "+ model+ " With "+ currentMiles +" is still covered under warranty"); } else System.out.println("Your car " + year+ " " + make+ " "+ model+ " With "+ currentMiles +" is out of warranty"); } } public class CertifiedPreOwnCar extends Car{ public CertifiedPreOwnCar(int y, String m, String mod, int mi) { super(mi, m, mod, y); } public int extendedWarrantyYears; public int extendedWarrantyMiles; public int getExtendedWarrantyYears() { return extendedWarrantyYears; } public void setExtendedWarrantyYears(int extendedWarrantyYears) { this.extendedWarrantyYears = extendedWarrantyYears; } public int getExtendedWarrantyMiles() { return extendedWarrantyMiles; } public void setExtendedWarrantyMiles(int extendedWarrantyMiles) { this.extendedWarrantyMiles = extendedWarrantyMiles; } public boolean isCoveredUnderWarranty() { if (currentMiles < extendedWarrantyMiles){ if (currentYear < (year+ extendedWarrantyYears)) return true; } return false; } } public class TestCar { public static void main(String[] args) { Car car1 = new Car(2014, "Honda", "Civic", 255); car1.setWarrantyMiles(60000); car1.setWarrantyYears(5); car1.checkWarrantyStatus(); Car car2 = new Car(2000, "Ferrari", "F355", 8500); car2.setWarrantyMiles(20000); car2.setWarrantyYears(7); car2.checkWarrantyStatus(); CertifiedPreOwnCar car3 = new CertifiedPreOwnCar(2000, "Honda", "Accord", 65000); car3.setWarrantyYears(3); car3.setWarrantyMiles(30000); car3.setExtendedWarrantyMiles(100000); car3.setExtendedWarrantyYears(7); car3.checkWarrantyStatus(); } }

    Read the article

  • inheritance from the django user model results in error when changing password

    - by Jerome
    I inherited form the django user model like so: from django.db import models from django.contrib.auth.models import User, UserManager from django.utils.translation import ugettext_lazy as _ class NewUserModel(User): custom_field_1 = models.CharField(_('custom field 1'), max_length=250, null=True, blank=True) custom_field_2 = models.CharField(_('custom field 2'), max_length=250, null=True, blank=True) objects = UserManager() When i go to the admin and add an entry into this model, it saves fine, but below the "Password" field where it has this text "Use '[algo]$[salt]$[hexdigest]' or use the change password form.", if i click on the "change password form' link, it produces this error Truncated incorrect DOUBLE value: '7/password' What can i do to fix this?

    Read the article

  • Using inheritance with multiple files in Ruby

    - by Preethi Jain
    I am new to Ruby . I have a question with respect to using Inheritence in Ruby . I have a class called as Doggy inside a file named Doggy.rb class Doggy def bark puts "Vicky is barking" end end I have written another class named Puppy in another file named puppy.rb class Puppy < Doggy end puts Doggy.new.bark I am getting this Error: Puppy.rb:1:in `<main>': uninitialized constant Doggy (NameError) Is it mandatory to have these classes (Doggy and Puppy ) inside a single file only? Edited As per the suggestions , i have tried using require and require_relative as shown , but still i am getting below Error Puppy.rb:1:in `<main>': uninitialized constant Doggy (NameError) class Puppy < Doggy end require_relative 'Doggy.rb' puts Doggy.new.bark

    Read the article

  • ASP.NET configuration inheritance

    - by NowYouHaveTwoProblems
    I have an ASP.NET application that defines a custom configuration section in web.config. Recently I had a customer who wanted to deploy two instances of the application (for testing in addition to an existing production application). The configuration chosen by the customer was: foo.com - production application foo.com/Testing - test application In this case, the ASP.NET configuration engine decided to apply the settings at foo.com/web.config to foo.com/Testing/web.config. Thankfully this caused a configuration error because the section was redefined at the second level rather than giving the false impression that the two web applications were isolated. What I would like to do is to specify that my configuration section is not inherited and must be re-defined for any web application that requires it but I haven't been able to find a way to do this. My web.config ends up something like this <configuration> <configSections> <section name="MyApp" type="MyApp.ConfigurationSection"/> </configSections> <MyApp setting="value" /> <NestedSettingCollection> <Item key="SomeKey" value="SomeValue" /> <Item key="SomeOtherKey" value="SomeOtherValue" /> </NestedSettingCollection> </MyApp> </configuration>

    Read the article

  • NSString inheritance

    - by Stef
    Hi, I'm doing an useless thing for my first step in Obj-C @interface String : NSString { int m_isnull; } - (id) init; - (int) isNull; @end @implementation String - (id) init { self = [super init]; m_isnull=1; return self; } - (int) isNull { return m_isnull; } @end test : String *a; a=@"ok"; Works fine, but just 2 little questions 1) When I'm compiling I have this warning warning: incompatible Objective-C types assigning 'struct NSString *', expected 'struct String *' I don't know how to avoid it !? 2) a=@"ok" is a fastest way to initialize a string, but when I'm debugging, I don't stop by at my init constructor why ?

    Read the article

  • enable_shared_from_this and inheritance

    - by DeadMG
    I've got a type which inherits from enable_shared_from_this<type>, and another type that inherits from this type. Now I can't use the shared_from_this method because it returns the base type and in a specific derived class method I need the derived type. Is it valid to just construct a shared_ptr from this directly? Edit: In a related question, how can I move from an rvalue of type shared_ptr<base> to a type of shared_ptr<derived>? I used dynamic_cast to verify that it really was the correct type, but now I can't seem to accomplish the actual move.

    Read the article

  • Objects with inheritance memory storage

    - by nikitas350
    Say that i have some classes like this example. class A { int k, m; public: A(int a, int b) { k = a; m = b; } }; class B { int k, m; public: B() { k = 2; m = 3; } }; class C : private A, private B { int k, m; public: C(int a, int b) : A(a, b) { k = b; m = a; } }; Now, in a class C object, are the variables stored in a specific way? I know what happens in a POD object, but this is not a POD object...

    Read the article

  • C# Generics Multiple Inheritance Problem

    - by Ciemnl
    Can any one help me with this syntax issue with C#? I have no idea how to do it. class SomeClass<T> : SomeOtherClass<T> where T : ISomeInterface , IAnotherInterface { ... } I want SomeClass to inherit from SomeOtherClass and IAnotherInterface and for T to inherit ISomeInterface only It seems the problem is that the where keyword screws everything up so that the compiler thinks both ISomeInterface and IAnotherInterface should both be inherited by T. This problem is very annoying and I think the solution is some kind of parenthesis but I have tried and failed finding one that works. Also, switching around the order of the two items inherited from SomeClass does not work because the class inherited always has to come before any interfaces. I couldn't find any solutions on the MSDN C# generics pages and I can't beleive I'm the first person to have this problem. Thanks, any help is much appreciated!

    Read the article

  • How to point a subdomain to local server with dynamic IP

    - by jlego
    I see there are many related questions to this one, however the answers given seem to be a little vague for a novice like me. I've got a dedicated LAMP stack running Fedora 16 locally on my home network. Everything works fine internally. I can access the Apache server from other machines on the network using the internal IP in a browser. I'm using the stack for a local file server as well as a development environment for websites. There are a couple of reasons why I would like the development sites hosted on the machine to be available publicly. 1.) I use a CMS that has paid add-ons which allows you to assign the paid license to a domain. I can't develop with paid add-ons on the closed dev server. 2.) I would occasionally like for clients to be able to view the site dev at late stages before it goes live. I have a domain (foo.com, and I want to point a *sub*domain (dev.foo.com) to the local server. I know this is best accomplished with a Static IP, however my IP from my ISP is Dynamic and I don't think there is any way to change that. From what I have read, services like ZoneEdit & DynDNS are supposed to be able to accomplish this, but I have tried both and found it very confusing. Also the server is behind a router and I have also read that you need to set up DDNS(?) in your router, that many routers have presets for these services, and I've found that DynDNS is the only one my router seems to support.

    Read the article

  • Access Home Network Server via External Address

    - by Dominic Barnes
    For the last few months, I've been using a server on my home network for basic backups and hosting some small websites. Up until this past week, I've been using Comcast (cable) as an ISP and now that I've moved into an apartment, I'm using AT&T. (DSL) I've set up dynamic DNS and I can verify it works externally. However, I can't seem to access the public address from within the local network. Is there something DSL does differently from Cable that makes this frustration possible?

    Read the article

  • Configure EasyBox (Vodafone) with DynDNS

    - by furtelwart
    How can I configure an EasyBox A601 WLAN (from Arcor resp. Vodafone) to send the IP always to DynDNS? I entered the following: Dynamic DNS [X] Diensteanbieter (DynDNS.org) Domänenname mysupersecrethost.dyndns.org (as specified in "My Host" section Konto / E-mail myaccountname Passwort mysupersecretpassword The update does not work anymore, so that my IP is not correct. The firmware is the newest available: Firmware Version: 10.02.006 (01.12.2008-11:11:59) Thanks for any hints!

    Read the article

  • Why can't I access my own web server from my local network?

    - by frenetic
    I have a web server in my home network and I'm using ZoneEdit for dynamic DNS. It's accessible perfectly to everyone outside of my local network, but since I switched to a Gateway 2Wire DSL modem/router I'm unable to use the domain to access the server from my network. I can access it via a local IP or by putting it in my Windows hosts file but this is annoying to do on every computer and for every subdomain. Any idea how I can fix this? Thanks!

    Read the article

  • Why can't I access my own web server from my local network?

    - by frenetic
    I have a web server in my home network and I'm using ZoneEdit for dynamic DNS. It's accessible perfectly to everyone outside of my local network, but since I switched to a Gateway 2Wire DSL modem/router I'm unable to use the domain to access the server from my network. I can access it via a local IP or by putting it in my Windows hosts file but this is annoying to do on every computer and for every subdomain. Any idea how I can fix this? Thanks!

    Read the article

< Previous Page | 55 56 57 58 59 60 61 62 63 64 65 66  | Next Page >