is_unsigned template in C++

Last Updated : 19 Nov, 2018
The std::is_unsigned template of C++ STL is used to check whether the type is a unsigned arithmetic type or not. It returns a boolean value showing the same. Syntax:
template <class T > struct is_unsigned;
Parameters: This template contains single parameter T (Trait class) to check whether T is a unsigned arithmetic type or not. Return Value:This template returns a boolean value as shown below:
  • True: if the type is a un-signed arithmetic type.
  • False: if the type is a signed arithmetic type.
Below programs illustrate the std::is_unsigned template in C++ STL: Program 1: CPP
// C++ program to illustrate
// std::is_unsigned template

#include <iostream>
#include <type_traits>
using namespace std;

class gfg {
};

enum sam : unsigned {};
enum class raj : unsigned {};

int main()
{
    cout << boolalpha;
    cout << "is_unsigned:" << '\n';
    cout << "unsigned int:"
         << is_unsigned<unsigned int>::value << '\n';
    cout << "gfg:"
         << is_unsigned<gfg>::value << '\n';
    cout << "sam:"
         << is_unsigned<sam>::value << '\n';
    cout << "raj:"
         << is_unsigned<raj>::value << '\n';

    return 0;
}
Output:
is_unsigned:
unsigned int:true
gfg:false
sam:false
raj:false
Program 2: CPP
// C++ program to illustrate
// std::is_unsigned template

#include <iostream>
#include <type_traits>
using namespace std;

int main()
{
    cout << boolalpha;
    cout << "is_unsigned:" << '\n';
    cout << "signed char:"
         << is_unsigned<signed char>::value << '\n';
    cout << "unsigned char:"
         << is_unsigned<unsigned char>::value << '\n';
    cout << "signed int:"
         << is_unsigned<signed int>::value << '\n';

    return 0;
}
Output:
is_unsigned:
signed char:false
unsigned char:true
signed int:false
Program 3: CPP
// C++ program to illustrate
// std::is_unsigned template

#include <iostream>
#include <type_traits>
using namespace std;

int main()
{
    cout << boolalpha;
    cout << "is_unsigned:" << '\n';
    cout << "bool:"
         << is_unsigned<bool>::value << '\n';
    cout << "float:"
         << is_unsigned<float>::value << '\n';
    cout << "double:"
         << is_unsigned<double>::value << '\n';

    return 0;
}
Output:
is_unsigned:
bool:true
float:false
double:false
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