Question

So we know that foreach is something like :

template<class InputIterator, class Function>
  Function for_each(InputIterator first, InputIterator last, Function f)
  {
    for ( ; first!=last; ++first ) f(*first);
    return f;
  }

I have implemented a

template <typename T>
class Range

The problem is that when I use this function with the for_Each :

static void add1(float &v)
{
  ++v;
}

it go in infinite loop because of first “!=” last (it’s not first”<“last), so how people do when they implemente their own forward iterator to work with for_each ?

Answer 1

The problem of your approach is that your iterator increment operators do not change the iterator, but rather the stored value. This means that inside the for_each loop, the condition is modified both in the increment operator of the iterator and also through the function.