std::make_signed in C++ with Examples

The std::make_signed template of C++ STL is present in the <type_traits> header file. The std::make_signed template of C++ STL is used to get the signed type corresponding to T(Triat class), by keeping any cv-qualifiers. It can be checked using std::is_same::value function whether the given type T is signed type or not. Header File:

#include<type_traits>

Template Class:

template< class T >
struct make_signed;

template<class T>
using make_signed_t 
    = typename make_signed<T>::type;

Syntax:

std::make_signed<T>::type

Parameter: The template std::make_signed accepts a single parameter T(Trait class) and maked the type T as a signed type. Below is the program to demonstrate std::make_signed in C++: Program:

CPP

// C++ program to illustrate
// std::make_signed
// make_signed
#include <iostream>
#include <type_traits>
using namespace std;

// Declare enum
enum ENUM1 { a,
             b,
             c };

enum class ENUM2 : unsigned char { x,
                                   y,
                                   z };

// Driver Code
int main()
{

    // Declare variable using make_signed
    // for int, unsigned, const unsigned,
    // enum1 and enum2
    typedef make_signed<int>::type A;
    typedef make_signed<unsigned>::type B;
    typedef make_signed<const unsigned>::type C;
    typedef make_signed<ENUM1>::type D;
    typedef make_signed<ENUM2>::type E;

    cout << boolalpha;

    // Check if the above declared variables
    // are signed type or not
    cout << "A is signed type? "
         << is_same<int, A>::value
         << endl;

    cout << "B is signed type? "
         << is_same<int, B>::value
         << endl;

    cout << "C is signed type? "
         << is_same<int, C>::value
         << endl;

    cout << "D is signed type? "
         << is_same<int, D>::value
         << endl;

    cout << "E is signed type? "
         << is_same<int, E>::value
         << endl;

    return 0;
}

Output:

A is signed type? true
B is signed type? true
C is signed type? false
D is signed type? true
E is signed type? false

Reference: https://cplusplus.com/reference/type_traits/make_signed/

std::make_signed in C++ with Examples

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