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std::is_fundamental

STD：：是[医]基本

Defined in header ​​
template< class T > struct is_fundamental;​(since C++11)

如果T是基本类型%28，即算术类型，void，或nullptr_t%29，提供成员常量。value平等true.对于任何其他类型，value是false...

模板参数

T-a type to check

辅助变量模板

template< class T > inline constexpr bool is_fundamental_v = is_fundamental::value;​(since C++17)

继承自STD：积分[医]常量

成员常数

value statictrue if T is a fundamental type , false otherwise (public static member constant)

成员函数

operator boolconverts the object to bool, returns value (public member function)
operator() (C++14)returns value (public member function)

成员类型

TypeDefinition
value_typebool
typestd::integral_constant<bool, value>

可能的实施

模板<class T>结构是[医]基本：STD：：整数[医]常数<bool，std：：is[医]算术<T>*价值STD：：是[医]空隙<T>*价值STD：：是[医]相同<std：：nullptr[医]t，type Name std：：Remove[医]CV<T>*类型>：：Value>{}；

*。

例

二次

#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';
}

二次

产出：

二次

false
true
false
false
true
false
false

二次

另见

is_compound (C++11)checks if a type is compound type (class template)
is_arithmetic (C++11)checks if a type is arithmetic type (class template)
is_void (C++11)checks if a type is void (class template)

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在CreativeCommonsAttribution下授权-ShareAlike未移植许可v3.0。

http：//en.cppreference.com/w/cpp/type/is[医]基本

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