StringBuilder sb = new StringBuilder("Hello "); sb.Append("World!");
StringBuilder sb = new StringBuilder("The answer is: "); sb.Append(42);
char[] chars = {'H', 'e', 'l', 'l', 'o'}; StringBuilder sb = new StringBuilder(); sb.Append(chars);This will result in `sb` containing the string "Hello". The System.Text namespace contains the StringBuilder class, so it is part of the .NET Framework Base Class Library.