is_unsigned template in C++

In this article we will be discussing the working, syntax and examples of std::is_unsigned template in C++ STL.

is_unsigned is a template which comes under <type_traits> header file. This template is used to check whether the given type T is an unsigned type or not.

What are unsigned data types in C++?

Unsigned data types are those which we use knowing the values will not go in negative, like roll number, id of random numbers, etc.

To make a type as unsigned we use keyword unsigned as prefix of the data type like −

unsigned int;

unsigned float;

Syntax

template <class T>is_unsigned;

Parameters

The template can have only parameter of type T, and check whether T is an unsigned type or not.

Return value

It returns a Boolean value, true if the given type is an unsigned type, and false if the given type is not an unsigned type.

Example

Input: is_unsigned<unsigned int>::value;
Output: True

Input: is_unsigned<int>::value;
Output: False

Example

 Live Demo

#include <iostream>
#include <type_traits>
using namespace std;
class TP {
};
enum TP_1 : int {};
enum class TP_2 : int {};
int main() {
   cout << boolalpha;
   cout << "checking for is_unsigned:";
   cout << "\nint:" << is_unsigned<int>::value;
   cout << "\nTP:" << is_unsigned<TP>::value;
   cout << "\nTP_1:" << is_unsigned<TP_1>::value;
   cout << "\nTP_2:" << is_unsigned<TP_2>::value;
   return 0;
}

Output

If we run the above code it will generate the following output −

checking for is_unsigned:
Int: false
TP: false
TP_1: false
TP_2: false

Example

 Live Demo

#include <iostream>
#include <type_traits>
using namespace std;
int main() {
   cout << boolalpha;
   cout << "checking for is_unsigned:";
   cout << "\nfloat:" << is_unsigned<float>::value;
   cout << "\nSigned int:" << is_unsigned<signed int>::value;
   cout << "\nUnsigned int:" << is_unsigned<unsigned int>::value;
   cout << "\ndouble:" << is_unsigned<double>::value;
   return 0;
}

Output

If we run the above code it will generate the following output −

checking for is_signed:
Float: false
Signed int: false
Unsigned int: true
Double: false