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is_signed Class

Test if type is signed integer.

template<class Ty>
    struct is_signed;

Ty

The type to query.

An instance of the type predicate holds true if the type Ty is a signed integral type or a cv-qualified signed integral type, otherwise it holds false.

 

// std_tr1__type_traits__is_signed.cpp 
// compile with: /EHsc 
#include <type_traits> 
#include <iostream> 
 
struct trivial 
    { 
    int val; 
    }; 
 
int main() 
    { 
    std::cout << "is_signed<trivial> == " << std::boolalpha 
        << std::is_signed<trivial>::value << std::endl; 
    std::cout << "is_signed<int> == " << std::boolalpha 
        << std::is_signed<int>::value << std::endl; 
    std::cout << "is_signed<unsigned int> == " << std::boolalpha 
        << std::is_signed<unsigned int>::value << std::endl; 
    std::cout << "is_signed<float> == " << std::boolalpha 
        << std::is_signed<float>::value << std::endl; 
 
    return (0); 
    } 
 
is_signed<trivial> == false
is_signed<int> == true
is_signed<unsigned int> == false
is_signed<float> == false

Header: <type_traits>

Namespace: std

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