sample_tree_node_update Interface

# `sample_tree_node_update` Interface

A sample node updater.

This class serves to show the interface a node update functor needs to support.

Defined in: `sample_tree_node_update.hpp`

## Template Parameters

Parameter | Description | Default Value
    class Const_Node_Iterator
| Const node iterator type. | -
    class Node_Iterator
| Node iterator type. | -
    class Cmp_Fn
| Comparison functor. | -
    class Allocator
| Allocator type. | -

## Public Types and Constants

### Metadata definitions.

Type | Definition | Description
    metadata_type
    size_t
| Metadata type. This can be any type; size_t is merely an example.

## Protected Methods

### Conclassors, declassor, and related.

Method | Description
      sample_tree_node_update
      ()
| Default constructor. Must be default constructable.

### Operators.

Method | Description
    inline void
      operator()
      (node_iterator node_it,
        const_node_iterator end_nd_it) const
| Updates the rank of a node through a `node_iterator` `node_it`; `end_nd_it` is the end node iterator.