Hi! The net is overflowing with explanations of the "dreaded diamond problem". So is StackOverflow. I think I understand that bit, but I fail to translate that knowledge into comprehending something similar yet different. My question begins as a pure C++ question, but the answer might well branch over into MS-COM specifics. The genera...
I have a strange problem in my project. I have a class that inherits from a base class (which again inherits from another base class) and overrides a function. However, when that function is called it never calls the overridden function, but the base function. However, when I override that function in the middle class it is called. But ...
I have hierarchy of public interfaces like this: struct ISwitchable { /* Obtain pointer to another implemented interface of the same instance. */ virtual int switch(unsigned int interfaceId, void** pInstance) = 0; }; struct IFoo : public ISwitchable { /* Methods */ }; struct IBar : public ISwitchable { /* Methods */ }; struct ...
So I have this idea and I think it's basically impossible to implement in C++... but I want to ask. I read through chapter 15 of Stroustrup and didn't get my answer, and I don't think the billion other questions about inheritance diamonds answer this one, so I'm asking here. The question is, what happens when you inherit from two base c...
class Temp { private: ~Temp() {} friend class Final; }; class Final : virtual public Temp { public: void fun() { cout<<"In base"; } }; class Derived : public Final { }; void main() { Derived obj; obj.fun(); } The above code tries to achieve non-inheritable class (final). But using above code t...
Hi, i am currently working on a C++ project where i have an abstract interface that is implemented later on. The interface also has a implemented method which my implementation doesn't override. My problem is that when using my implementation, the compiler(MSVC) doesn't see the interface method. What causes this, and how can i resolve it...
Hi all! I have a problem with Visual Studio 2008 concerning virtual inheritance. Consider the following example: #include<iostream> class Print { public: Print (const char * name) { std::cout << name << std::endl; } }; class Base : public virtual Print { public: Base () : Print("Base") {} }; class A : ...
Problem: class Base { public: Base(Base* pParent); ... implements basic stuff... }; class A : virtual public Base { public: A(A* pParent) : Base(pParent) {} ... }; class B : virtual public Base { public: B(B* pParent) : Base(pParent) {} ... }; class C : public A, public B { public: C(C* pParent) : A(pParent), B(pParent) {} ...
Is there a way to define a class Foo in C++ so that I can inherit from it I can't "diamond inherit" from it I.e. class Cat: public Foo{} // okay class Dog: public Foo{} // okay class Weird: public Cat, public Dog {} // I want this to throw a compiler error ...
In the following code, it seems class C does not have access to A's constructor, which is required because of the virtual inheritance. Yet, the code still compiles and runs. Why does it work? class A {}; class B: private virtual A {}; class C: public B {}; int main() { C c; return 0; } Moreover, if I remove the default constr...
Hello, I'm working on a graphics application that is using virtual classes fairly extensively. It has: A picture class, which is essentially a collection of shapes. A shapes class, which is purely virtual and has a few classes that inherit from it: Circle Polygon Rectangle A Figure shape, which is any graphical figure (also virtual...
class Base { public: Base(){} Base(int k):a(k) { } int a; }; class X:virtual public Base { public: X():Base(10){} int x; }; class Y:virtual public Base { public: Y():Base(10){} int y; }; class Z:public X,public Y...
Hi there: I encounter this problem when tackling with virtual inheritance. I remember that in a non-virtual inheritance hierarchy, object of sub-class hold an object of its direct super-class. What about virtual inheritance? In this situation, does object of sub-class hold an object of its super-class directly or just hold a pointer poi...
I'm trying to derive a new class from an old one. The base class declaration looks like this: class Driver : public Plugin, public CmdObject { protected: Driver(); public: static Driver* GetInstance(); virtual Engine& GetEngine(); public: // Plugin methods... virtual bool InitPlugin (Mgr* pMgr); virtual bool Ope...
I am trying to refactor some code while leaving existing functionality in tact. I'm having trouble casting a pointer to an object into a base interface and then getting the derived class out later. The program uses a factory object to create instances of these objects in certain cases. Here are some examples of the classes I'm working w...
Consider the following class hierarchy: base class Object with a virtual method foo() an arbitrary hierarchy with multiple inheritance (virtual and non-virtual); each class is a subtype of Object; some of them override foo(), some don't a class X from this hierarchy, not overriding foo() How to determine which method will be executed...
I am little confused about vptr and representation of objects in the memory, and hope you can help me understand the matter better. Consider B inherits from A and both define virtual functions f(). From what I learned the representation of an object of class B in the memory looks like this:[ vptr | A | B ] and the vtbl that vptr points...
Hi all, I am trying to inherit two equally named methods with different parameter lists to a derived class. One of them is virtual and overridden in the derived class, the other one is non-virtual. Doing so, i get a compile error while trying to access the non-virtual method of the base class from an derived class object. Here is the ...
I understand the basics of C++ virtual inheritance. However, I'm confused about where exactly I need to use the virtual keyword with a complex class hierarchy. For example, suppose I have the following classes: A / \ B C / \ / \ D E F \ / \ / G H \...
I have never seen a class used as virtual and nonvirtual base (i.e. if some class is intended to be an ancestor then we usually know in advance about type of inheritance - virtual or nonvirtual). So I suppose that there is an error-prone freedom in c++ to specialize "virtual" inheritance in base class list. It should be better to specif...