quick sort http://stackoverflow.com/questions/36962336, C++ (clang)

quick sort http://stackoverflow.com/questions/36962336

Language: Layout:

//clang 3.7.0
#include <array>
#include <iostream>
#include <algorithm>

template<typename Iterator>
Iterator partition(Iterator first, Iterator last)
{
	auto pivot = last - 1;
	auto less_end = first;
	for (auto iter = first; iter != pivot; ++iter)
	{
		if (*iter <= *pivot)
		{
			std::swap(*less_end++, *iter);
		}
	}
	std::swap(*(less_end), *pivot);
	return less_end;
}

template<typename Iterator>
void quick_sort(Iterator first, Iterator last)
{
	if (last - first > 1)
	{
		auto pivot = partition(first, last);
		quick_sort(first, pivot);
		quick_sort(pivot + 1, last);
	}
}

template <class T, std::size_t N>
std::ostream& operator<<(std::ostream& o, const std::array<T, N>& arr)
{
	std::copy(arr.cbegin(), arr.cend(), std::ostream_iterator<T>(o, " "));
	return o;
}

int main()
{
    std::array<int, 5> src = {{ 1,2,3,4,5 }};
	do {
		std::array<int, 5> arr(src);
		std::cout << arr << " -> ";
		quick_sort(std::begin(arr), std::end(arr));
		std::cout << arr << std::endl;

if (!std::is_sorted(std::begin(arr), std::end(arr))) {
			std::cout << "ouch" << std::endl;
			break;
		}
	} while (std::next_permutation(std::begin(src), std::end(src)));
	return 0;
}

Show compiler warnings [ + ] Compiler args [ + ] Show input
Compilation time: 0.62 sec, absolute running time: 0.13 sec, cpu time: 0 sec, memory peak: 3 Mb, absolute service time: 0,76 sec

1 2 3 4 5 -> 1 2 3 4 5 1 2 3 5 4 -> 1 2 3 4 5 1 2 4 3 5 -> 1 2 3 4 5 1 2 4 5 3 -> 1 2 3 4 5 1 2 5 3 4 -> 1 2 3 4 5 1 2 5 4 3 -> 1 2 3 4 5 1 3 2 4 5 -> 1 2 3 4 5 1 3 2 5 4 -> 1 2 3 4 5 1 3 4 2 5 -> 1 2 3 4 5 1 3 4 5 2 -> 1 2 3 4 5 1 3 5 2 4 -> 1 2 3 4 5 1 3 5 4 2 -> 1 2 3 4 5 1 4 2 3 5 -> 1 2 3 4 5 1 4 2 5 3 -> 1 2 3 4 5 1 4 3 2 5 -> 1 2 3 4 5 1 4 3 5 2 -> 1 2 3 4 5 1 4 5 2 3 -> 1 2 3 4 5 1 4 5 3 2 -> 1 2 3 4 5 1 5 2 3 4 -> 1 2 3 4 5 1 5 2 4 3 -> 1 2 3 4 5 1 5 3 2 4 -> 1 2 3 4 5 1 5 3 4 2 -> 1 2 3 4 5 1 5 4 2 3 -> 1 2 3 4 5 1 5 4 3 2 -> 1 2 3 4 5 2 1 3 4 5 -> 1 2 3 4 5 2 1 3 5 4 -> 1 2 3 4 5 2 1 4 3 5 -> 1 2 3 4 5 2 1 4 5 3 -> 1 2 3 4 5 2 1 5 3 4 -> 1 2 3 4 5 2 1 5 4 3 -> 1 2 3 4 5 2 3 1 4 5 -> 1 2 3 4 5 2 3 1 5 4 -> 1 2 3 4 5 2 3 4 1 5 -> 1 2 3 4 5 2 3 4 5 1 -> 1 2 3 4 5 2 3 5 1 4 -> 1 2 3 4 5 2 3 5 4 1 -> 1 2 3 4 5 2 4 1 3 5 -> 1 2 3 4 5 2 4 1 5 3 -> 1 2 3 4 5 2 4 3 1 5 -> 1 2 3 4 5 2 4 3 5 1 -> 1 2 3 4 5 2 4 5 1 3 -> 1 2 3 4 5 2 4 5 3 1 -> 1 2 3 4 5 2 5 1 3 4 -> 1 2 3 4 5 2 5 1 4 3 -> 1 2 3 4 5 2 5 3 1 4 -> 1 2 3 4 5 2 5 3 4 1 -> 1 2 3 4 5 2 5 4 1 3 -> 1 2 3 4 5 2 5 4 3 1 -> 1 2 3 4 5 3 1 2 4 5 -> 1 2 3 4 5 3 1 2 5 4 -> 1 2 3 4 5 3 1 4 2 5 -> 1 2 3 4 5 3 1 4 5 2 -> 1 2 3 4 5 3 1 5 2 4 -> 1 2 3 4 5 3 1 5 4 2 -> 1 2 3 4 5 3 2 1 4 5 -> 1 2 3 4 5 3 2 1 5 4 -> 1 2 3 4 5 3 2 4 1 5 -> 1 2 3 4 5 3 2 4 5 1 -> 1 2 3 4 5 3 2 5 1 4 -> 1 2 3 4 5 3 2 5 4 1 -> 1 2 3 4 5 3 4 1 2 5 -> 1 2 3 4 5 3 4 1 5 2 -> 1 2 3 4 5 3 4 2 1 5 -> 1 2 3 4 5 3 4 2 5 1 -> 1 2 3 4 5 3 4 5 1 2 -> 1 2 3 4 5 3 4 5 2 1 -> 1 2 3 4 5 3 5 1 2 4 -> 1 2 3 4 5 3 5 1 4 2 -> 1 2 3 4 5 3 5 2 1 4 -> 1 2 3 4 5 3 5 2 4 1 -> 1 2 3 4 5 3 5 4 1 2 -> 1 2 3 4 5 3 5 4 2 1 -> 1 2 3 4 5 4 1 2 3 5 -> 1 2 3 4 5 4 1 2 5 3 -> 1 2 3 4 5 4 1 3 2 5 -> 1 2 3 4 5 4 1 3 5 2 -> 1 2 3 4 5 4 1 5 2 3 -> 1 2 3 4 5 4 1 5 3 2 -> 1 2 3 4 5 4 2 1 3 5 -> 1 2 3 4 5 4 2 1 5 3 -> 1 2 3 4 5 4 2 3 1 5 -> 1 2 3 4 5 4 2 3 5 1 -> 1 2 3 4 5 4 2 5 1 3 -> 1 2 3 4 5 4 2 5 3 1 -> 1 2 3 4 5 4 3 1 2 5 -> 1 2 3 4 5 4 3 1 5 2 -> 1 2 3 4 5 4 3 2 1 5 -> 1 2 3 4 5 4 3 2 5 1 -> 1 2 3 4 5 4 3 5 1 2 -> 1 2 3 4 5 4 3 5 2 1 -> 1 2 3 4 5 4 5 1 2 3 -> 1 2 3 4 5 4 5 1 3 2 -> 1 2 3 4 5 4 5 2 1 3 -> 1 2 3 4 5 4 5 2 3 1 -> 1 2 3 4 5 4 5 3 1 2 -> 1 2 3 4 5 4 5 3 2 1 -> 1 2 3 4 5 5 1 2 3 4 -> 1 2 3 4 5 5 1 2 4 3 -> 1 2 3 4 5 5 1 3 2 4 -> 1 2 3 4 5 5 1 3 4 2 -> 1 2 3 4 5 5 1 4 2 3 -> 1 2 3 4 5 5 1 4 3 2 -> 1 2 3 4 5 5 2 1 3 4 -> 1 2 3 4 5 5 2 1 4 3 -> 1 2 3 4 5 5 2 3 1 4 -> 1 2 3 4 5 5 2 3 4 1 -> 1 2 3 4 5 5 2 4 1 3 -> 1 2 3 4 5 5 2 4 3 1 -> 1 2 3 4 5 5 3 1 2 4 -> 1 2 3 4 5 5 3 1 4 2 -> 1 2 3 4 5 5 3 2 1 4 -> 1 2 3 4 5 5 3 2 4 1 -> 1 2 3 4 5 5 3 4 1 2 -> 1 2 3 4 5 5 3 4 2 1 -> 1 2 3 4 5 5 4 1 2 3 -> 1 2 3 4 5 5 4 1 3 2 -> 1 2 3 4 5 5 4 2 1 3 -> 1 2 3 4 5 5 4 2 3 1 -> 1 2 3 4 5 5 4 3 1 2 -> 1 2 3 4 5 5 4 3 2 1 -> 1 2 3 4 5