Creating and Printing an Array in C#

private void btnCreate_Click(object sender, System.EventArgs e)
{
   int [] a = new int[7];
   a[0] = a[1] = 1;
   for (int i = 2; i < 7; ++i)
      a[i] = a[i - 1] + a[i - 2];
   string Fibonacci = a[4].ToString();
   MessageBox.Show(
     "The fifth number in the Fibonacci series is " +
        Fibonacci,
     "Arrays", MessageBoxButtons.OK, MessageBoxIcon
        .Information);
}