#include <type_traits>

template < class T, class... Args >
struct is_nothrow_constructible;

std::is_nothrow_constructible< T, Args..>::value

//C++中std::is_nothrow_constructible的演示程序
#include <bits/stdc++.h>
#include <type_traits>
using namespace std;
// 声明结构体
struct X {
};
struct Y {
    Y() {}
    Y(X&)
    noexcept {}
};
struct Z {
    int n;
    Z() = default;
};
int main()
{
    cout << boolalpha;
    cout << "int is_nothrow_constructible? "
          << is_nothrow_constructible<int>::value
          << endl;
    cout << "X() is is_nothrow_constructible? "
          << is_nothrow_constructible<X>::value
          << endl;
    cout << "Y(X) is is_nothrow_constructible? "
          << is_nothrow_constructible<Y,X>::value
          << endl;
    cout << "Z() is is_nothrow_constructible? "
          << is_nothrow_constructible<Z>::value
          << endl;
    return 0;
}

int is_nothrow_constructible? true
X() is is_nothrow_constructible? true
Y(X) is is_nothrow_constructible? false
Z() is is_nothrow_constructible? true

// C++程序演示std::is_nothrow_constructible
#include <bits/stdc++.h>
#include <type_traits>

using namespace std;

// GfG类
class GfG {
    int v1;
    float v2;

public:
    GfG(int n)
        : v1(n), v2()
    {
    }
    GfG(int n, double f) noexcept : v1(n), v2(f) {}
};

// 声明结构体

struct X {
    int n;
    X() = default;
};

// 主函数
int main()
{

    cout << boolalpha;

    cout << "GfG是否能从int构造而来? "
          << is_nothrow_constructible<GfG, int>::value
          << '\n';

    cout << "GfG是否能从int和float构造而来? "
          << is_nothrow_constructible<GfG, int, float>::value
          << '\n';

    cout << "GfG是否能从结构体X构造而来? "
          << is_nothrow_constructible<GfG, X>::value
          << '\n';
}

GfG是否能从int构造而来? false
GfG是否能从int和float构造而来? true
GfG是否能从结构体X构造而来? false