std::iterator_traits

#include <iostream>
#include <iterator>
#include <vector>
#include <list>
 
template<class BDIter>
void my_reverse(BDIter first, BDIter last)
{
    typename std::iterator_traits<BDIter>::difference_type n = std::distance(first, last);
    --n;
    while(n > 0) {
        typename std::iterator_traits<BDIter>::value_type tmp = *first;
        *first++ = *--last;
        *last = tmp;
        n -= 2;
    }
}
 
int main()
{
    std::vector<int> v{1,2,3,4,5};
    my_reverse(v.begin(), v.end());
    for(int n : v)
        std::cout << n << ' ';
    std::cout << '\n';
 
    std::list<int> l{1,2,3,4,5};
    my_reverse(l.begin(), l.end());
    for(auto n : l)
        std::cout << n << ' ';
    std::cout << '\n';
 
//    std::istreambuf_iterator<char> i1(std::cin), i2;
//    my_reverse(i1, i2); // compilation error
 
}