C++ 模板 Traits

写一个简单的累加模板，如下：

template<typename T>
T accum(T const* beg, T const* end)
{
   
   
	T total{
   
   };
	while(beg != end)
	{
   
   
		total += * beg;
		++ beg;
	}
	return total;
}


int main()
{
   
   

	int num[] = {
   
    1, 2, 3, 4, 5 };
	std::cout << "the average value of the integer values is "
		<< accum(num, num + 5) / 5
		<<std::endl;

	char name[] = "templates"; 
	int length = sizeof(name) - 1;// (try to) print average character value
	std::cout << "the average value of the characters in \""
		<< name << "\" is "
		<< accum(name, name + length) / length << std::endl;
	return 0;