std::vector<int> arr;

    arr.push_back(0); arr.push_back(1); arr.push_back(2);

    std::vector<int>::iterator it    = arr.begin();
    std::vector<int>::iterator itEnd = arr.end();

    auto oFn = [](const int& n) { return 2 <= n; };

    if ( std::find_if<std::vector<int>::iterator&, decltype(oFn)>(it, itEnd, oFn) != itEnd )
    {
        *it = 5;
    }

BFE>    std::vector<int> arr;

BFE>    arr.push_back(0); arr.push_back(1); arr.push_back(2);

BFE>    std::vector<int>::iterator it    = arr.begin();
BFE>    std::vector<int>::iterator itEnd = arr.end();

BFE>    auto oFn = [](const int& n) { return 2 <= n; };

BFE>    if ( std::find_if<std::vector<int>::iterator&, decltype(oFn)>(it, itEnd, oFn) != itEnd )
BFE>    {
BFE>        *it = 5;
BFE>    }
BFE>

25.2.5.1
Returns: The first iterator i in the range [first,last) for which the following corresponding conditions hold: *i == value, pred(*i) != false, pred(*i) == false. Returns last if no such iterator is found.

...
find_if(InputIterator first, InputIterator last, Predicate pred)
{
    auto iter = first;
    while(iter != last)
    {
    if(pred(*iter))
        {
            break;
        }
        ++iter;
    }
    return(iter);
}

...
find_if(InputIterator first, InputIterator last, Predicate pred)
{
    auto iter = first;
    while(iter != last)
    {
    if(pred(*iter))
        {
            break;
        }
        ++iter;
    }
    first = last;
    return(iter);
}

    std::cout << "std::is_copy_assignable<std::vector<int>::iterator&>::value " << std::is_copy_assignable<std::vector<int>::iterator&>::value << std::endl;
    std::cout << "std::is_move_assignable<std::vector<int>::iterator&>::value " << std::is_move_assignable<std::vector<int>::iterator&>::value << std::endl;

std::is_copy_assignable<std::vector<int>::iterator&>::value 1
std::is_move_assignable<std::vector<int>::iterator&>::value 1

VTT>...
VTT>find_if(InputIterator first, InputIterator last, Predicate pred)
VTT>{
VTT>    auto iter = first;
VTT>...
VTT>    return(iter);
VTT>}
VTT>

VTT>...
VTT>find_if(InputIterator first, InputIterator last, Predicate pred)
VTT>{
VTT>    auto iter = first;
VTT>...
VTT>    return(iter);
VTT>}
VTT>

std::vector<int> test = {1,2,6,7};
std::find_if(std::begin(test), std::end(test), [](int& current){
   if (current >= 2)
   {
      current = 5;
      return true;
   }
   return false;
});

25.2.5 Find [alg.find]
template<class InputIterator, class T> InputIterator find(InputIterator first, InputIterator last, const T& value);

template<class InputIterator, class Predicate> InputIterator find_if(InputIterator first, InputIterator last, Predicate pred);

template<class InputIterator, class Predicate> InputIterator find_if_not(InputIterator first, InputIterator last, Predicate pred);

1 Returns: The first iterator i in the range [first,last) for which the following corresponding conditions hold: *i == value, pred(*i) != false, pred(*i) == false. Returns last if no such iterator is found.

2 Complexity: At most last — first applications of the corresponding predicate.

template<class T> T fun(T t);

  int n = 32;
  ink k = fun<int&>(n);