gistfile1.txt

//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    public class Program
    {
        
        public static char FirstNonRepeatedChar(char compareChar, string sentence, int compareCharPos)
        {

            //checking if last char of passed sentence is reached
            if (sentence.Length == compareCharPos)
            {
                //checking if passed char exists once in passed sentence.
                if (sentence.Count(obj => obj == compareChar) == 1)
                    //return the last sentence char as the first none repeated char
                    return sentence[sentence.Length - 1];
                else
                    //the sentence does not contains any non repeated char
                    return '\0';
            }
            //checking if passed char exists once in passed sentence.
            else if (sentence.Count(obj => obj == compareChar) == 1)
            {
                //return the current method call compare char as the first none repeated char
                return compareChar;
            }
            else
            {
                //the current method call compare char exists more than once and the primitive case of recursion is not reached yet
                //So call the method recursively with compareCharPos incremented by 1
                return FirstNonRepeatedChar(sentence[compareCharPos], sentence, compareCharPos + 1);
            }
        }
        
        
        public static void Main(string[] args)
        {
            //Your code goes here
            Console.WriteLine("Hello, world!");
            Console.WriteLine(Program.FirstNonRepeatedChar('r',"total", 0));
        }
    }
}