using System;

using System.Text.RegularExpressions;

​

public class Program

{

    public static void Main()

    {

        string[] reloc = new string[10];

        reloc[0] = "test";

        reloc[1] = "test2";

        reloc[2] = "eat";

        reloc[3] = "like";

        string text = "I test you and I eat you";

        Console.WriteLine(reloc.Length);

        for (int idx = 0; idx < reloc.Length; idx++)

        {

            if (idx % 2 == 0) {

                if (reloc[idx] != null && reloc[idx + 1] != null) {

                    text = Regex.Replace(text, reloc[idx], reloc[idx + 1]);

                }

            }

        }

        Console.WriteLine("Output: " + text);

    }

}