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std::is_array

STD：：是[医]列阵

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

检查是否T是数组类型。提供成员常量。value等于true，如果T是数组类型。否则，value等于false...

模板参数

T-a type to check

辅助变量模板

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

继承自STD：积分[医]常量

成员常数

value statictrue if T is an array 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]数组：std：：false[医]类型{}；模板<class T>结构是[医]数组<T。[]>：std：：true[医]类型{}；模板<类T，std：：size[医]tN>struct是[医]数组<Tn>：STD：：真[医]{}型；

*。

例

二次

#include <iostream>
#include <type_traits>
 
class A {};
 
int main() 
{
    std::cout << std::boolalpha;
    std::cout << std::is_array<A>::value << '\n';
    std::cout << std::is_array<A[]>::value << '\n';
    std::cout << std::is_array<A[3]>::value << '\n';
    std::cout << std::is_array<float>::value << '\n';
    std::cout << std::is_array<int>::value << '\n';
    std::cout << std::is_array<int[]>::value << '\n';
    std::cout << std::is_array<int[3]>::value << '\n';
}

二次

产出：

二次

false
true
true
false
false
true
true

二次

另见

rank (C++11)obtains the number of dimensions of an array type (class template)
extent (C++11)obtains the size of an array type along a specified dimension (class template)
remove_extent (C++11)removes one extent from the given array type (class template)
remove_all_extents (C++11)removes all extents from the given array type (class template)

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

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