using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace CheckSum
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            Console.InputEncoding = Encoding.UTF8;
            Console.OutputEncoding = Encoding.UTF8;
            using var sha = SHA512.Create();
            while (true)
            {
                Console.WriteLine("input file name:");
                var file = Console.ReadLine();
                if (File.Exists(file))
                {
                    Console.WriteLine(BitConverter.ToString(sha.ComputeHash(File.ReadAllBytes(file))).Replace("-", "").ToLower());
                }
                else
                {
                    Console.WriteLine($"file {file} does not Exist");
                }
                var key = Console.ReadKey().Key;
                if (key == ConsoleKey.Enter || key == ConsoleKey.Escape)
                {
                    break;
                }
            }
        }
    }
}