merge_sort.h

#ifndef MERGE_SORT_H
#define MERGE_SORT_H
 
#include <algorithm> // Required for std::inplace_merge
#include <iostream>
#include <vector>

template <typename Iter> void merge_sort(Iter begin, Iter end) {
    if (end - begin > 1) {
        Iter mid = begin + (end - begin) / 2; // Assumes Random Access Iterator
        merge_sort(begin, mid);
        merge_sort(mid, end);
        std::inplace_merge(begin, mid,
                           end); // Elements must be comparable and move-assignable
    }
}
 
#endif // MERGE_SORT_H