HashSet removing element

using System;//  j  a  v a2  s.co m
using System.Collections.Generic;

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

        for (int i = 0; i < 20; i++)
        {
            evenNumbers.Add(i);
        }


        Console.Write("evenNumbers contains {0} elements: ", evenNumbers.Count);

        if (evenNumbers.Contains(0))
        {
            evenNumbers.Remove(0);
        }

        Console.Write("evenNumbers contains {0} elements: ", evenNumbers.Count);
    }
}

using System;/*from  jav  a2 s  .  com*/
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        HashSet<int> Numbers = new HashSet<int>();

        for (int i = 0; i < 10; i++)
        {
            Numbers.Add(i);
        }

        Console.Write("Numbers contains {0} elements: ", Numbers.Count);

        Numbers.Clear();
        Numbers.TrimExcess();

        Console.Write("Numbers contains {0} elements: ", Numbers.Count);
    }
}