I coded this up in a few min, but it had a bug in it until I tested it. I work at Allscripts and probably would have failed the interview. I also cannot code well in C# without VS and the intellisense to let me know all the methods available and what the params are. Allscripts is a great company and we are hiring now in Raleigh. It all depends on the group you get into. I love working here and recommend it to anyone looking for dev positions. public class StringManipulations { public string reverse(string s1) { // Instantiate a StringBuilder from a string. StringBuilder sb1 = new StringBuilder(s1); int i = s1.Length-1; int count =0; foreach (char x in s1.ToCharArray()) { sb1.Replace(x, s1[i--], count++,1); } return (sb1.ToString()); } }