#include <iostream>
#include <numeric>
#include <type_traits>
#include <utility>
 
using namespace std;
 
template<class InputIterator>
using yourType = typename std::decay<decltype(*std::declval<InputIterator>())>::type;
 
template<class InputIterator>
yourType<InputIterator> mean(InputIterator first, InputIterator last) 
{
	return std::accumulate(first, last, yourType<InputIterator>()) / std::distance(first, last);
}
 
int main()
{
	double vals[] = { 1, 3, 5, 6, 3, 2 };
	auto kk = mean(begin(vals), end(vals));
	cout << kk << endl;
	return 0;
}

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