c++ - Getting range of vector without creating a new subvector -

i'm trying create recursive function each time accepts vector, this:

std::vector<int> mergesort(std::vector<int> &main_vector) {  //.......... rest of code .......    middle = get_midpoint(unsorted_vector);   first_temp.insert(first_temp.begin(), main_vector.begin(), middle);   second_temp.insert(second_temp.begin(), middle, main_vector.end());   first_half = mergesort(first_temp);   second_half = mergesort(second_temp);    //.......... rest of code .......    return main_vector;  } 

here i'm trying pass vector each time call function mergesort again. had create 2 temporary vectors first_temp , second_temp, because don't know how extract range main_vector without creating new temporary vector hold value.

is there way won't need create holder vectors ? main_vector[0:n] or ?

traditional way use iterator range:

template <typename iterator> void mergesort(iterator begin, iterator end) {   const auto middle = get_midpoint_it(begin, end);    // .......... rest of code .......    mergesort(begin, middle);   mergesort(middle, end);    // .......... rest of code ....... } 

with library range-v3, may use range directly:

template <typename range> void mergesort(range&& range) {   const auto middle = get_midpoint_index(range);    // .......... rest of code .......    mergesort(range | ranges::view::slice(0, middle));   mergesort(range | ranges::view::slice(middle, (int) range.size()));    // .......... rest of code ....... }