using System;
using System.Collections.Generic;

namespace EgoDelegate
{
    public static class HashSetExtension
    {
        public static void DisplaySet(this HashSet<int> set)
        {
            Console.Write("{");
            foreach( int i in set)
            {
                Console.Write(" {0}", i);
            }
            Console.WriteLine(" }");
        }

        public static void ForEach<T>(this IEnumerable<T> source, Action<T> action)
        {
            foreach (T element in source)
            {
                action(element);
            }
        }
    }


    class Damn
    {
        static void Main()
        {
            HashSet<int> evenNumbers = new HashSet<int>();
            HashSet<int> oddNumbers = new HashSet<int>();

            for (int i = 0; i < 5; i++)
            {
                evenNumbers.Add(i * 2);
                oddNumbers.Add((i * 2) + 1);
            }

            evenNumbers.DisplaySet();
            oddNumbers.DisplaySet();

            // union of two sets
            HashSet<int> uniformedSet = new HashSet<int>(evenNumbers);
            uniformedSet.UnionWith(oddNumbers);
            uniformedSet.ForEach(x => Console.Write(x + " "));

        }
    }
}