using System;

using System.Text;

public class Program

{

    public static void Main()

    {

        // Buggy test

        Console.WriteLine(ResolvePropertyNameBuggy("HelloWorld"));

        Console.WriteLine(ResolvePropertyNameBuggy("anotherTest"));

        Console.WriteLine("");

        // Fixed test

        Console.WriteLine(ResolvePropertyNameFixed("HelloWorld"));

        Console.WriteLine(ResolvePropertyNameFixed("anotherTest"));

    }

    private static string ResolvePropertyNameBuggy(string propertyName)

            {

                StringBuilder sb = new StringBuilder();

                for (int i = 0; i < propertyName.Length; i++)

                {

                    if (Char.IsUpper(propertyName[i]))

                    {

                        sb.Append(Char.ToLowerInvariant(propertyName[i]));

                        if (i != 0)

                        {

                            sb.Append('_');

                        }

                    }

                    else

                    {

                        sb.Append(propertyName[i]);

                    }

                }

​

                return sb.ToString(); 

            }

    private static string ResolvePropertyNameFixed(string propertyName)

            {

                StringBuilder sb = new StringBuilder();

                for (int i = 0; i < propertyName.Length; i++)

                {

                    if (Char.IsUpper(propertyName[i]))

                    {

                        if (i != 0)

                        {

                            sb.Append('_');

                        }

                        sb.Append(Char.ToLowerInvariant(propertyName[i]));

                    }

                    else

                    {

                        sb.Append(propertyName[i]);

                    }

                }

​

                return sb.ToString(); 

            }

}