#include <iostream>
using namespace std;

template <typename T>
void f(T* arr, int size) {
    for (int i = 0; i  + 1 < size; i += 2) {
        T tmp = arr[i];
        arr[i] = arr[i + 1];
        arr[i + 1] = tmp;
    }
}

int main() {
    int arr[] = { 2, 3, 1, 0, 6, 5 };

    f(arr, size(arr));
    for (int i = 0; i < size(arr); ++i) {
        cout << arr[i] << ' ';
    }

    return 0;
}