virtual

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<<endl;} int getI() const {return i;} void setI(int j) {i=j;} }; class ControlPanel { public: Vir *v; ControlPanel(const ControlPanel& c)//copy constructor { v=new Handler; v->setI(c.getI()); } int getI()const {return v->getI();} void initialize() {v=new Handler(10);} void hi() {v->hi();}

I have a class which is supposed to be abstract. In one of it's abstract methods the return type may be an instance of class1,class2 or class3, depending on the class that's implementing the method. I'm wondering how should I declare the method in the abstract class. I thought about using dynamic typing, but I want the return type to be restricted to one of the 3 classes, not every type, and in addition I'm not sure I can override it so that in the inheriting class the return type will not match the return type in the abstract class. I'd be glad if you could help me with this, Tnx! Take a look

class A { A() {}; virtual ~A() {}; virtual void Start() {}; virtual void Start(float a) {}; }; class B : public A { }; class C : public A { virtual void Start(float a) {}; } ... B BObj; BObj.Start(); // -> fine, no complain from g++ ... ... C CObj; CObj.Start(); // -> not fine -> error: no matching function for call to ‘C::Start()’ ... I suspect that the problem comes from that both virtual functions have the same name, but different parameter signature. What I would like to know is that this is a g++-specific error message, how it is implemented the vtable, or it is an error based on the C++

I was curious about C++ and virtual inheritance - in particular, the way that vtable conflicts are resolved between bass and child classes. I won't pretend to understand the specifics on how they work, but what I've gleamed so far is that their is a small delay caused by using virtual functions due to that resolution. My question then is if the base class is blank - ie, its virtual functions are defined as: virtual void doStuff() = 0; Does this mean that the resolution is not necessary, because there's only one set of functions to pick from? Forgive me if this is an stupid question - as I said

The following code (from C++ FAQs 24.11) is implementing virtual assignment operator overloading and overriding: #include <iostream> using namespace std; class B{ public: virtual ~B() throw(); virtual B& operator= (const B& b) throw(); }; B::~B() throw(){} B& B::operator= (const B& b) throw() { cout << "B::operator=(const B&)\n"; return *this; } class D : public B{ public: virtual D& operator= (const B& b) throw(); D& operator= (const D& d) throw(); }; D& D::operator= (const B& b) throw() {cout << "D::operator= (const B&)\n"; return *this;} D& D::operator= (const D& d) throw() {cout << "D:

My question is: is there a way to set up a virtual display as default display on a linux server (so that all GUI application launched will be displayed on that display, if no counter indication is made)? I tried using this: xvfb-run java -jar autoclick.jar , which produces the following output : searching graphic devices is Headless:false screen N°1 width:1600 height:900 just 1 robot click: Magic button clicked ! and here's the autoclick code : System.out.println("searching graphic devices"); System.out.println("is Headless:"+GraphicsEnvironment.isHeadless()); GraphicsEnvironment ge =