using System;

using System.Linq;

using System.Text;

​

public class Program

{

    public static void Main()

    {

        var array = new string[] { null, "String 1", null, "String 2 Trailing Spaces     ", "     ", "End of String   " } ;

        var looping = Looping(array);

        var linq = Linq(array);

        Console.WriteLine(looping == linq);

        Console.WriteLine(linq);

    }

    public static string Looping(string[] recipientLabelArray)

    {

        StringBuilder recipientLabel = new StringBuilder();

        int i;

​

        if (recipientLabelArray != null)

        {

            for (i = 0; i < recipientLabelArray.Length; i++)

            {

                string label = recipientLabelArray[i];

​

                if (label != null)

                {

                    label = label.Trim();

​

                    if (!string.IsNullOrEmpty(label))

                    {

                        recipientLabel.Append(label);

​

                        if (i < recipientLabelArray.Length - 1)

                        {

                            recipientLabel.Append(Environment.NewLine);

                        }

                    }

                }

            }

        }

        return recipientLabel.ToString();

    }

    public static string Linq(string[] array)

    {

        return

            string.Join(

                Environment.NewLine,

                array.Select(s => s != null ? s.Trim() : s)

                     .Where(s => !string.IsNullOrEmpty(s)));

    }

}