C# Program to Implement Principles of Delegates

/*
 *  C# Program to Implement Principles of Delegates
 */
 
using System;
class Program
{
      delegate string UppercaseDelegate(string input);
      static string UppercaseFirst(string input)
      {
        char[] buffer = input.ToCharArray();
        buffer[0] = char.ToUpper(buffer[0]);
        return new string(buffer);
      }
      static string UppercaseLast(string input)
      {
        char[] buffer = input.ToCharArray();
        buffer[buffer.Length - 1] = char.ToUpper(buffer[buffer.Length - 1]);
        return new string(buffer);
      }
      static string UppercaseAll(string input)
      {
        return input.ToUpper();
      }
      static void WriteOutput(string input, UppercaseDelegate del)
      {
        Console.WriteLine("Input String: {0}", input);
        Console.WriteLine("Output String: {0}", del(input));
      }
      static void Main()
      {
        WriteOutput("tom ", new UppercaseDelegate(UppercaseFirst));
        WriteOutput("tom", new UppercaseDelegate(UppercaseLast));
        WriteOutput("tom", new UppercaseDelegate(UppercaseAll));
        Console.ReadLine();
      }   
}