Question

This is the Range class :

template <typename T>
class Range
{
public:
  class iterator;

  Range(T low, T high) : low_(low), high_(high)
  {
  }

  const iterator begin() const
  {
    return iterator(low_);
  }

  const iterator end() const
  {
    return iterator(high_);
  }

};

Which king of iterator (forward, random, input) is the best to choose ?

Answer 1

You can provide any type of iterator, including if you wish a random iterator, as long as you do not allow modification of the iterator state from operator* or operator->. That is, if you are keeping the count in the iterator, then operator* should return a T (value) and operator-> a T const *, so that the iteration cannot be modified through these operators.