A sample ranged-hash functor.
This class serves to show the interface a ranged-hash functor needs to support.
| Method | Description | 
| sample_ranged_hash_fn () | Default constructor. Must be default constructible. | 
| sample_ranged_hash_fn (const sample_ranged_hash_fn &r_other) | Copy constructor. Must be copy constructible. | 
| inline void swap (sample_ranged_hash_fn &r_other) | Swaps content. Must be swappable (if there is such a word). |