// clang++ 3.5

// maybe gcc 4.9 support it, but I don't test it

#include<iostream>

int main()

{

    auto fac = [&](auto&& self, int x)->int{

        return x <  ?  : x * self(self, x - );

    };

    std::cout<<fac(fac, )<<std::endl; //

    return ;

}

作者：蓝色

链接：https://www.zhihu.com/question/27441424/answer/36643770

来源：知乎

著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。

// clang++ 3.5

// maybe gcc 4.9 support it, but I don't test it

#include<iostream>

template<typename Functor>

struct wrapper_type

{

    Functor functor;

    template<typename... Args>

    decltype(auto) operator()(Args&&... args) const&

    {

        return functor(functor, std::forward<Args>(args)...);

    }

};

template<typename Functor>

wrapper_type<typename std::decay<Functor>::type> wrapper(Functor&& functor)

{

    return{ std::forward<Functor>(functor) };

}

int main()

{

    auto fac = wrapper([&](auto&& self, int x)->int{

        return x <  ?  : x * self(self, x - );

    });

    std::cout << fac() << std::endl; //

    return ;

}

作者：蓝色

链接：https://www.zhihu.com/question/27441424/answer/36643770

来源：知乎

著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。

#include <iostream>

#include <typeinfo>

#include <functional>

using namespace std;

int main(void)

{

    std::function<int(int)> product;

    product = [&product](int n) -> int{ return n <= ?  : n * product(n - ); };

    cout << "The answer is: " << product() << endl;

} 

链接：https://blog.csdn.net/zenny_chen/article/details/6045596