#include <iostream>
#include <algorithm>
#include <iterator>
using namespace std;

int main() {
	int arr[] = {1, 2, 3, 4, 5, 6, 7, 8, 9};

	auto mid = std::partition(begin(arr), end(arr), [](int x){ return x%2;});

	auto out = ostream_iterator<int>(cout, ", ");
	cout << "odds: ";
 	copy(begin(arr), mid, out);
 	cout << "\nevens: ";
 	copy(mid, end(arr), out);
}