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Questions tagged [dynamic-cast]

The dynamic_cast conversion allows for safely converting pointers (and references) to classes up, down, and sideways in the inheritance hierarchy.

From cppreference.com:

Safely converts pointers and references to classes up, down, and sideways along the inheritance hierarchy.

dynamic_cast has usage scenarios and limitations. In general terms this amounts to it being valid for casting polymorphic types and it performs run-times checks to ensure that the result is valid for the requested object type.

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Why the constructor is called after a static cast?

This is my class: class AComponent : public nts::IComponent { public: AComponent(const size_t &maxInputs, const size_t &maxOutputs, const size_t &value); AComponent(nts::AComponent &); virtual ~AComponent(); virtual nts::Tristate…
Dimitri Danilov
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Why non-virtual function call is successful even after dynamic_cast is failed?

Below is code snippet, #include using namespace std; class A { public: void print() const { cout << "In A::print()\n"; } virtual void show() { cout << "In A::show()\n"; } }; class B : public…
Pravar Jawalekar
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reinterpret_cast and dynamic cast questions

I've read about reinterpret and dynamic cast, but I saw some examples which I have questions about. reinterpret_cast: #include using namespace std; class A { public: void a() { cout << "a"; } }; class B: private…
OferP
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Error with pointer when using dynamic_cast to detect derived class

I'd like to have some help on an issue I face. I made an inheritance with polymorph program with class Shape and Circle (derived from shape). So I have some code like this main.cpp Shape* shape = new (nothrow)…
Alvin
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Is there any way to dynamically cast the item type of a generics collection in Delphi?

Unlike the case with common objects, it is impossible to directly assign generics of different related types in Delphi as follows: Possible (normal objects): var var_1 : TObject; var_2 : MyTObjectSubClass; var_1 := var_2; //Works Not…
QuestionOverflow
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(Smart) pointers to a base class storing derived objects; is this correct & good practis?

I have the following piece of code where I have a smart pointer of a base class type unique_ptr. But I'd like to store a derived object with it new Bird(). Since it is a pointer this works well. Is this good practise or will I run into…
dani
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method chain a derived class method after calling a base class method

With a class and a derivative as shown below, is there a way for the base classes methods to return a object reference of the derived type instead of its own type so syntactically i can chain the methods together? Suppose that object A has methods…
Aage Torleif
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C++ dynamic_cast issue

class C1 { public: C1* A; void SomeMethod() { class C2; C2* c2 = dynamic_cast(A); } }; class C2 : public C1 {}; In gcc i'm getting "target is not a pointer or reference to complete type" when dynamic_cast is…
Jules Bianqi
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Static cast - Cannot cast through virtual inheritance

I was reading about static and dynamic casts along with the differences between them. It states that static_cast cannot cast through virtual inheritance however dynamic cast can. I would appreciate it if someone could clarify what this means…
Rajeshwar
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c++ static and dynamic type casting

Why static_cast<>() (also known as downcast) doesn't casts types run-time while dynamic_cast<>() (also known as upcast) does? Both are used to advance through class hierarchy. What could be so different between them that it is necessary for…
Ivars
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dynamic_cast from Base to Derived

I have a very general question, related to dynamic_cast in c++: Let's assume we have the following classes: class Father{ public: Father(...); // this is constructor //..... //.. Whatever code in here, not important ~…
user2750466
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C++ dynamic_cast

class A { }; class B:public A { }; int main() { A a; B b; A *ap = &b; B *bp = dynamic_cast(ap); if(bp!= NULL) cout<<"Pass"<
ranganath111
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issues with dynamic_cast in C++

I'm implementing inhomogeneous linked list (.cpp and .h files are below) in C++. Compiling in Linux using intel compiler with: icpc test.cpp List.cpp -o test gives lots of erros (see below). It seems that the problem originates from the lines…
user3428703
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Use static_cast to dynamic polymorphism

I used a static_cast to polymorphism. I read that I should use dynamic_cast, but I can't get why. Code works in both way (with static and dynamic cast). Could anybody show me an example with necessary dynamic_cast operator? class Base { …
KeyB0rys
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why does dynamic_cast return null with multiple level inheritance

While reviewing an inherited project which is to port from an old version of Visual Studio (6) to a new version (2017), we stumbled across this run time error, in that we were getting an unexpected NULL after using dynamic_cast<>() on a base class.…
Gio
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