C# printf function

format.cs

private static string PrintF(params object[] a)
{
  if (a == null || a.Length == 0) return string.Empty;
  int[] i = { 1 };
  string s = (a[0] is string) ? System.Text.RegularExpressions.Regex.Replace((string)a[0], "%[sdi%]",
    match => match.Value == "%%" ? "%" : i[0] < a.Length ? a[i[0]++].ToString() : match.Value) : a[0].ToString();
  for (; i[0] < a.Length; i[0]++)
    s += " " + a[i[0]];
  return s;
}