fun_with_c++11.cpp

#include <iostream>

constexpr int fac(int n)
{
    return n <= 0 ? 1 : n * fac(n - 1);
}

struct [[weenie]] C {
    void f() && { std::cout << "dying C's last gasp!\n"; }
    void f() & { std::cout << "living, breathing C\n"; }

    int mvar;
};

class D {
    public:
        D(int x) : x_(x) {}

    private:
        int x_;
};

class alignas(alignof(double)) E : public D {
    public:
        using D::D;
        E() : E(47) {}
};

template<typename T> void g(const T& t)
{
    std::cout << t.y << '\n';
}

using temperature = double;

inline constexpr long double operator"" _degC (long double val)
{
    return val;
}

inline constexpr long double operator"" _degF (long double val)
{
    return val * (9.0 / 5.0) + 32.0;
}

template<class... Numeric> struct sum_result;

template<class Numeric1, class... Numeric>
struct sum_result<Numeric1, Numeric...> {
    typedef decltype(
            Numeric1() +
            typename sum_result<Numeric...>::result_type())
        result_type;
};

template<class Numeric>
struct sum_result<Numeric> {
    typedef Numeric result_type;
};

template<class Numeric>
auto sum(Numeric n) -> Numeric { return n; }

template<class Numeric1, class... Numeric>
auto sum(Numeric1 n, Numeric... rest)
-> typename sum_result<Numeric1, Numeric...>::result_type
{ return n + sum(rest...); }

int main()
{
    int huh[fac(5)];

    temperature cold = -23.0_degF, hot = 40.0_degC;

    thread_local int x = 6;
    std::cout << "sizeof(C::mvar) is " << sizeof(C::mvar) << '\n';
    C().f();

    C c;
    c.f();

    struct huzzah {
        int y = 5;
    } h;

    g(h);

    E e;

    std::cout << "1 + 2.0 + 3u + 7.5f = " << sum(1, 2.0, 3u, 7.5f) << '\n';

#if __cplusplus > 201103L
    auto f = [](auto x) { return x * 5; };
    std::cout << "f(3) = " << f(3) << '\n';
    std::cout << "f(3.2) = " << f(3.2) << '\n';
    std::cout << "f('0') = " << f('0') << '\n';
#endif
}