std::is_unsigned
From cppreference.com
Defined in header
<type_traits>
|
||
template< class T >
struct is_unsigned; |
(since C++11) | |
If T
is an unsigned arithmetic type, provides the member constant value
equal true. For any other type, value
is false.
Contents |
Inherited from std::integral_constant
Member constants
value
[static]
|
true if T is an unsigned arithmetic type , false otherwise (public static member constant) |
Member functions
operator bool |
converts the object to bool, returns value (public member function) |
operator()
(C++14)
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returns value (public member function) |
Member types
Type | Definition |
value_type
|
bool
|
type
|
std::integral_constant<bool, value> |
[edit] Possible implementation
namespace detail { template<typename T,bool = std::is_arithmetic<T>::value> struct is_unsigned : std::integral_constant<bool, T(0) < T(-1)> {}; template<typename T> struct is_unsigned<T,false> : std::false_type {}; } // namespace detail template<typename T> struct is_unsigned : detail::is_unsigned<T>::type {}; |
[edit] Example
Run this code
#include <iostream> #include <type_traits> class A {}; enum B : unsigned {}; enum class C : unsigned {}; int main() { std::cout << std::boolalpha; std::cout << std::is_unsigned<A>::value << '\n'; std::cout << std::is_unsigned<float>::value << '\n'; std::cout << std::is_unsigned<signed int>::value << '\n'; std::cout << std::is_unsigned<unsigned int>::value << '\n'; std::cout << std::is_unsigned<B>::value << '\n'; std::cout << std::is_unsigned<C>::value << '\n'; }
Output:
false false false true false false
[edit] See also
(C++11)
|
checks if a type is signed arithmetic type (class template) |
(C++11)
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checks if a type is floating-point type (class template) |
(C++11)
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checks if a type is integral type (class template) |
(C++11)
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makes the given integral type signed (class template) |
(C++11)
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makes the given integral type unsigned (class template) |
(library fundamentals TS)
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variable template alias of std::is_unsigned::value (variable template) |