C# Cookbook

10.7. Creating an n-ary Tree

Problem

You need a tree that can store a number of child nodes in each of its nodes. A binary tree would work if each node needs to have only two children, but, in this case, each node needs to have a fixed number of child nodes greater than two.

Solution

Use the following NTree class to create the root node for the n-ary tree:

using System;
using System.Collections;

public class NTree
{
    public NTree( ) 
    {
        maxChildren = int.MaxValue;
    }

    public NTree(int maxNumChildren) 
    {
        maxChildren = maxNumChildren;
    }

    // The root node of the tree
    protected NTreeNodeFactory.NTreeNode root = null;
    // The maximum number of child nodes that a parent node may contain
    protected int maxChildren = 0;

    public void AddRoot(NTreeNodeFactory.NTreeNode node)
    {
        root = node;
    }

    public NTreeNodeFactory.NTreeNode GetRoot( )
    {
        return (root);
    }

    public int MaxChildren
    {
        get {return (maxChildren);}
    }
}

The methods defined in Table 10-6 are of particular interest to using an NTree object.

Table 10-6. Members of the NTree class

Member	Description
Overloaded constructor	This constructor creates an NTree object. Its syntax is: NTree(int maxNumChildren) where maxNumChildren is the maximum number of children that one node may have at any time.
MaxChildren property	A read-only property to retrieve the maximum number of children any node may have. Its syntax is: int MaxChildren {get;} The value this property returns is set in the constructor.
AddRoot method	Adds a node to the tree. Its syntax ...