Implementation of depth first search or DFS in C#.

DFS.cs

public class Tree<K, V>
    where K : class, IComparable<K>
    where V : class
{
    private Node<K, V> root;

    public V DFS(K key) 
    {
        Stack<Node<K, V>> stack = new Stack<Node<K, V>>();
        
        while(stack.Any())
        {
            var node = stack.Pop();

            if(node.key == key)
            {
                return node.value;
            }
            foreach (var child  in node.children)
            {
                stack.Push(child);
            }
        }
        return default(V);
    }

    private class Node<K, V>
        where K : class, IComparable<K>
        where V : class
    {
        public K key;
        public V value;
        public Node<K, V>[] children;
    }
}