I have three classes: class A {}; class B : virtual public A {}; class C : virtual public A {}; class D: public B, public C {}; Attempting a static cast from A* to B* I get the below error: cannot convert from base A to derived type B via virtual base A ...
why if we have pure virtual assignment operator in a base class, then we implement that operator on the derived class, it give linker error on the base class? currently I only have the following explanation on http://support.microsoft.com/kb/130486 , it said that the behavior is by design since normal inheritance rules does not apply. ...
Hey all, I am trying to make a thing where in other applications you can print to a certain printer and python will get the data. How would I go about making this? It would have to work in all applications, so it would appear as a normal printer, and work on Linux and Windows, even if I have to rewrite it for both. So to recap: One op...
Hello all, I saw the following snippet code: class Foo { public: void virtual func() throw (int, float) = 0; }; class Bar : public Foo { public: void virtual func() throw(short); // line 1: compile error " // looser throw specifier" void...
#include <iostream> using namespace std; class base { public: void f() {cout << "base" << endl;} virtual void v() {cout << "base (virtual)" << endl;} }; class deriv : public base { public: void f() {cout << "deriv" << endl;} void v() {cout << "deriv (overridden)" << endl;} }; int main() ...
I have a .NET_4 Managed C++ ref class that I derive from a .NET_4 base class written in C#. EXAMPLE:: { C# BASE CLASS:: namespace Core { public class ResourceManager { public class _Resource { public virtual void Delete() {} } } } } MANAGED C++ CLASS namspace Input.DI { public ref class Mouse : ResourceManager...
What are the rules for accessibility when virtual functions are declared under 3 different access specifiers specified by C++(public, private, protected) What is the significance of each? Any simple code examples to explain the concept will be highly useful. ...
I wanted to make a special version of shared_ptr that would perform specific operations when it was created or destroyed, but my plans appear to be foiled by the realization that shared_ptr's destructor is non virtual, meaning when I override it, my pointers never get cleaned up when the last instance of them are destroyed. The only al...
How does Virtual Method Invocation work in C++? ...
My objective is to do a deep copy of a class, but a virtual class is causing trouble. #include<iostream> using namespace std; class Vir//pure virtual class { public: virtual void hi()=0; }; class Handler:public Vir { public: int i; Handler() {} Handler(int val):i(val) {} void hi() {cout<<"Value of i="<<i<<e...
Because of my device I can't use virtual functions. Suppose I have: class Base { void doSomething() { } }; class Derived : public Base { void doSomething() { } }; // in any place { Base *obj = new Derived; obj->doSomething(); } the obj->doSomething() will call just the Base::doSomething() Is there a way with Base *o...
Possible Duplicate: Why do we not have a virtual constructor? I know this has been asked before but I didn't understand the complex technical words used in the other answers. I read on a community the reason that constructors cannot be virtual is The ‘virtual’ mechanism works on a logically complete (completely constructe...
#include<iostream> using namespace std; class Abs { public: virtual void hi()=0; }; class B:public Abs { public: void hi() {cout<<"B Hi"<<endl;} void bye() {cout<<"B Bye"<<endl;} }; class C:public Abs { public: void hi() {cout<<"C Hi"<<endl;} void sayonara() {cout<<"C Sayo...
Apparently my app needs 2.5 MB (maybe because my photos need 2MB...) and then virtual device can't work with that much MB. How can I make my virtual device support more than 2.5 MB to get my application working? ...
#include<iostream> using namespace std; class Something { public: int j; Something():j(20) {cout<<"Something initialized. j="<<j<<endl;} }; class Base { private: Base(const Base&) {} public: Base() {} virtual Base *clone() { return new Base(*this); } virtual void ID() { cout<<"BASE"<<endl; } }; class Derived ...
I would like to know if there is a solution to control a "virtual web browser" with any language (but preferably PHP or C#). This "virtual web browser" would be have just like a normal one, but it is completely hidden from the user. This means the Javascript is executed and javascript cookies handled. I want to use this to login to a si...
Is it possible to have a "virtual touchpad" or "virtual trackball" on a touchscreen monitor? I have several monitors and only one of them is touchscreen. I am trying to do away with the mouse and keyboard for an app I am working on and would like to use only the touchscreen. I need something like a virtual touchpad on my touchscreen mo...
Does a pure-virtual object have a pointer to the vtbl? (that probably points to NULL?) thanks, i'm a little bit confused with all the virtual mechanism. ...
#include <iostream> #include <string> class A { public: A(int a) : _a(a) {} virtual ~A() {} virtual void f() const {std::cout << _a << std::endl;} private: int _a; }; class B : public A { public: B(int a, int b) : A(a), _b(b) {} virtual void f() const {std::cout << _b << std::endl;} private: int _b; }; int mai...
I have a Delphi application that reads/writes to a COM port connected to a large hardware device, so I don't usually have the hardware available during development. That said, the communication protocol is fairly simple, so I can generally do the development and have someone onsite test it, and it usually works. Occasionally I run into...