std::is_fundamental
Материал из cppreference.com
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| Заголовочный файл <type_traits>
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| template< class T > struct is_fundamental; |
(начиная с C++11) | |
Если
T является одним из основных типов (то есть арифметический тип, void, или nullptr_t), обеспечивает постоянный член value равных true. Для любого другого типа, value является false.Original:
If
T is a fundamental type (that is, arithmetic type, void, or nullptr_t), 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.
Содержание |
Унаследован от std::integral_constant
Member constants
| value [static] |
true если T is a fundamental type , false иначе Original: true if T is a fundamental 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. (public static константа-член) |
Member functions
| operator bool |
преобразует объект в bool, возвращает 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. (public функция-член) |
Member types
| Type
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
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type
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std::integral_constant<bool, value> |
[править] Возможная реализация
template< class T> struct is_fundamental : std::integral_constant< bool, std::is_arithmetic<T>::value || std::is_void<T>::value || std::is_same<std::nullptr_t, typename std::remove_cv<T>::type>::value > {}; |
[править] Пример
#include <iostream> #include <type_traits> class A {}; int main() { std::cout << std::boolalpha; std::cout << std::is_fundamental<A>::value << '\n'; std::cout << std::is_fundamental<int>::value << '\n'; std::cout << std::is_fundamental<int&>::value << '\n'; std::cout << std::is_fundamental<int*>::value << '\n'; std::cout << std::is_fundamental<float>::value << '\n'; std::cout << std::is_fundamental<float&>::value << '\n'; std::cout << std::is_fundamental<float*>::value << '\n'; }
Вывод:
false true false false true false false
[править] См. также
| (C++11) |
проверяет, является ли тип соединения типа Original: checks if a type is compound type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (шаблон класса) |
| (C++11) |
проверяет, является ли тип арифметического типа Original: checks if a type is arithmetic type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (шаблон класса) |
| (C++11) |
проверяет, является ли тип void Original: checks if a type is void The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (шаблон класса) |