C#

int N = arrayOfLastNames.Length;
           for (int a = 0; a < arrayOfLastNames.Length; a++)
           {
               int W = arrayOfLastNames[a].Length;
               Console.WriteLine("{0}", W);

               string[] temp = new string[arrayOfLastNames.Length];
               for (int d = W - 1; d >= 0; d--)
               {
                   int[] count = new int[50];
                   for (int i = 0; i < N; i++)
                   {
                       count[arrayOfLastNames[i][d] + 1]++; //this is the part that causes the IndexOutOfRange exception
                   }
                   for (int k = 1; k < 256; k++)
                   {
                       count[k] += count[k - 1];
                   }
                   for (int i = 0; i < N; i++)
                   {
                       temp[count[arrayOfLastNames[i][d]]++] = arrayOfLastNames[i];
                   }
                   for (int i = 0; i < N; i++)
                   {
                       arrayOfLastNames[i] = temp[i];

                       Console.WriteLine("{0}", arrayOfLastNames[i]);
                   }
               }
           }

private void  SubNetCountCombo_SelectedIndexChanged(System.Object sender, System.EventArgs e)
{
    HostCountCombo.SelectedIndex = SubNetCountCombo.SelectedIndex;
    newsubnetmaskcombo.SelectedIndex = SubNetCountCombo.SelectedIndex; 
}

private void  HostCountCombo_SelectedIndexChanged(object sender, System.EventArgs e)
{
    SubNetCountCombo.SelectedIndex = HostCountCombo.SelectedIndex;
    newsubnetmaskcombo.SelectedIndex = HostCountCombo.SelectedIndex; 
}
private void  newsubnetmaskcombo_SelectedIndexChanged(System.Object sender, System.EventArgs e)
{
    SubNetCountCombo.SelectedIndex = newsubnetmaskcombo.SelectedIndex;
    HostCountCombo.SelectedIndex = newsubnetmaskcombo.SelectedIndex; 
}