C# - String Operations

using System;

namespace LearnCS
{
    class Program
    {
        static void Main(string[] args)
        {
            string someString = "Of all things i've lost i miss my mind the most";

            Console.WriteLine("Length: " + someString.Length);

            Console.WriteLine("To Upper: " + someString.ToUpper());
            Console.WriteLine("To Lower: " + someString.ToLower());

            string oneMore = " Hack The Planet";

            string result = string.Concat(someString, oneMore);
            Console.WriteLine(result);

            string interpolation = $"First One: {someString} and Second One: {oneMore}";
            Console.WriteLine(interpolation);

            Console.WriteLine(someString[0]);
            Console.WriteLine(someString[1]);
            Console.WriteLine(someString[2]);
            Console.WriteLine(someString[3]);
            Console.WriteLine(someString[4]);

            Console.WriteLine(someString.IndexOf("t"));
            Console.ReadLine();
        }
    }        
}