using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ExtensionMethod
{
    class Program
    {
        static void Main(string[] args)
        {
            string s = "This is a Test";

            string s2 = s.ToChangeCase();
            Console.WriteLine(s2);

            bool found = s.Found('T');
            Console.WriteLine(found);
        }
    }
}