std::is_signed - cppreference.com

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Elemento definito nell'header `<type_traits>`

`template< class T > struct is_signed;`		(dal C++11)

Se T è un tipo aritmetico firmato, prevede il membro costante value true uguali. Per qualsiasi altro tipo, è value false.

Original:

If T is a signed arithmetic type, provides the member constant value equal true. For any other type, value is false.

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Inherited from std::integral_constant

Member constants


	`true` se `T` is a signed arithmetic type , `false` altrimenti Original: `true` if `T` is a signed arithmetic 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. (pubblico membro statico costante)

Member functions


	converte l'oggetto in `bool`, restituisce `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. (metodo pubblico)

Member types


Tipo 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`	`bool`

`type`	`std::integral_constant<bool, value>`

Esempio

#include <iostream>
#include <type_traits>

class A {};
enum B : int {};
enum class C : int {};

int main() 
{
    std::cout << std::boolalpha;
    std::cout << std::is_signed<A>::value << '\n';
    std::cout << std::is_signed<float>::value << '\n';
    std::cout << std::is_signed<signed int>::value << '\n';
    std::cout << std::is_signed<unsigned int>::value << '\n';
    std::cout << std::is_signed<B>::value << '\n';
    std::cout << std::is_signed<C>::value << '\n';
}

Output:

false
true
true
false
false
false

Vedi anche


is_unsigned (C++11)	Verifica se un tipo è di tipo aritmetico senza segno Original: checks if a type is unsigned arithmetic type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe template) [modifica]

is_signed [statico]	identifica i tipi di firma Original: identifies signed types The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (pubblico of `std::numeric_limits` membro statico costante) [modifica]

is_floating_point (C++11)	Verifica se un tipo è tipo a virgola mobile Original: checks if a type is floating-point type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe template) [modifica]

is_integral (C++11)	controlla se un tipo è di tipo integrale Original: checks if a type is integral type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe template) [modifica]

make_signed (C++11)	rende il dato tipo integrale firmato Original: makes the given integral type signed The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe template) [modifica]

make_unsigned (C++11)	rende il dato tipo integrale senza segno Original: makes the given integral type unsigned The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe template) [modifica]