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using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace ReadAndWrite
{
    class TextFileRead
    {
        static void Main(string[] args)
        {
            string filePath = @"C:\atm\test.txt";

            // string[] lines = File.ReadAllLines(filePath);

            List<string> lines = new List<string>();
            lines = File.ReadAllLines(filePath).ToList();


            // lines.Add("Julian4, Clown, fdjiaf.smurf.com");
            lines.Add("123456789,Smile");
            File.WriteAllLines(filePath, lines);


            string input = "123456789,Smile";
            foreach (string line in lines)
            {
                if (line == input)
                {
                    Console.WriteLine("Valid");
                }
                else
                {
                    Console.WriteLine("Not Valid");
                }

            }
            


        }
    }
}