C ++ 11中最小和最大可变参数模板变体？

#define LessThanComparable class
#include <boost/type_traits/common_type.hpp>


/*! Multi-Type Minimum of \\p a. */
template <LessThanComparable T> const T & multi_type_min (const T & a) { return a; } // template termination
/*! Multi-Type Minimum of \\p a, \\p b and \\p args. */
template <class T, class ... R >
//requires SameType <T , Args >...
T multi_type_min(const T & a, const T & b, const R &... args)
{
    return multi_type_min(a < b ? a : b, args...);
}

/*! Minimum of \\p a. */
template <LessThanComparable T> const T & min(const T & a) { return a; } // template termination
/*! Minimum of \\p a, \\p b and \\p args. */
template <class T, class U, class ... R, class C = typename boost::common_type<T, U, R...>::type >
C min(const T & a, const U & b, const R &... c)
{
    return min(static_cast<C>(a < b ? a : b), static_cast<C>(c)...);
}

int b = min( 1,2,a,b,5 );

template <class T>
T _real_min_(T a, std::initializer_list<T> s) {
    T *res = &a;
    for (auto it = s.begin(); it != s.end(); ++it) {
        *res = *(it) < *res ? *it : *res;
    }
    return *res;
}

template <class T, class... ArgTypes>
T min(T a, ArgTypes... args) {
  return _real_min_(a, {args...});
}