C++ (策略）

#include <iostream>
using namespace std;

namespace _nmsap1
{
	template<typename T>
	struct SumFixedTraits;

	template<>
	struct SumFixedTraits<char>
	{
		using sumT = int;
		static sumT initValue() { return 0; }
	};
	template<>
	struct SumFixedTraits<int>
	{
		using sumT = __int64;
		static sumT initValue() { return 0; }
	};
	template<>
	struct SumFixedTraits<double>
	{
		using sumT = double;
		static sumT initValue() { return 0.0; }
	};

	template<typename T>
	struct MinFixedTraits;

	template<>
	struct MinFixedTraits<int>
	{
		using sumT = __int64;
		static sumT initValue() { return INT64_MAX; }
	};

	template<typename sumT, typename T>
	struct SumPolicy
	{
		static void algorithm(sumT &sum, const T& value)
		{
			sum += value;
		}
	};
	template <typename minT, typename T>
	struct  MinPolicy
	{
		static void algorithm(minT& min, const T&value)
		{
			if (min > value)
				min = value;
		}
	};

	template<typename T, typename U = SumFixedTraits<T>, 
						//typename V = SumPolicy>
					     template<class, class>class V = SumPolicy>
	auto funcsum(const T*begin, const T*end)
	{
		//using sumT = typename SumFixedTraits<T>::sumT;
		//sumT sum = SumFixedTraits<T>::initValue();
		typename U::sumT sum = U::initValue();

		for (;;)
		{
			//sum += (*begin);
			V<U::sumT, T>::algorithm(sum, *begin);
			if (begin == end)
				break;
			++begin;
		}
		return sum;
	}
}

int main()
{
	//char charArr[] = "abc";
	//cout << (int)(_nmsap1::funcsum(&charArr[0], &charArr[2])) << endl;
	int intArr[] = {10, 30, 5, 50, 20};
	cout << (int)(_nmsap1::funcsum<int, _nmsap1::MinFixedTraits<int>, _nmsap1::MinPolicy>(&intArr[0], &intArr[2])) << endl;
	return 0;
}