std::is_abstract
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Defined in header <type_traits>
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template< class T > struct is_abstract; |
(depuis C++11) | |
Si
T
est une classe abstraite (c'est-à-dire une classe qui hérite déclare ou au moins une fonction virtuelle pure), fournit du membre de constante value
true égale. Pour tout autre type, value
est false .Original:
If
T
is an abstract class (that is, a class that declares or inherits at least one pure virtual function), provides the member constant value
equal true. For any other type, value
is false.The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
Sommaire |
Inherited from std::integral_constant
Member constants
value [ statique ]Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
true si T is an abstract class type , false autrement Original: true if T is an abstract class type , false otherwise The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (constante membre statique publique) |
Member functions
operator bool |
convertit l'objet en bool, retourne value Original: converts the object to bool, returns value The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction membre publique) |
Member types
Type d'
Original: Type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
Definition |
value_type
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bool
|
type
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std::integral_constant<bool, value> |
[modifier] Notes
Les classes abstraites ne peuvent être utilisés comme classes de base, pas des objets d'un type de classe abstraite ne peut être créé que sous forme de sous-objets de classe de base .
Original:
Abstract classes may only be used as base classes; no objects of an abstract class type can be created except in form of base class subobjects.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
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Une classe abstraite peut être dérivée d'une classe qui n'est pas abstraite si une fonction virtuelle pure remplace une fonction virtuelle qui n'est pas pur .
Original:
An abstract class may be derived from a class that is not abstract if a pure virtual function overrides a virtual function that is not pure.
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
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[modifier] Exemple
#include <iostream> #include <type_traits> struct A { int m; }; struct B { virtual void foo(); }; struct C { virtual void foo() = 0; }; struct D : C {}; int main() { std::cout << std::boolalpha; std::cout << std::is_abstract<A>::value << '\n'; std::cout << std::is_abstract<B>::value << '\n'; std::cout << std::is_abstract<C>::value << '\n'; std::cout << std::is_abstract<D>::value << '\n'; }
Résultat :
false false true true
[modifier] Voir aussi
(C++11) |
checks if a type is a class type (but not union type) (classe générique) |
(C++11) |
vérifie si un type est le type de classe polymorphique Original: checks if a type is polymorphic class type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe générique) |