C# Program to validate email ID

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace validateemailid

{

    class Program

    {

        static void Main(string[] args)

        {

            Console.WriteLine("Enter the email id of user");

            string em;

            em = Console.ReadLine();

            if (em.Contains("@") && em.Contains("."))

            {

                if ((em.IndexOf('@') - em.IndexOf('.')) > 3)

                {

                    Console.WriteLine("valid email ID");

                }

                else

                {

                    Console.WriteLine("invalid Email ID");

                }

            }

            else

            {

                Console.WriteLine("invalid Email ID");

            }

        }

    }

}