AgeAfterTenYears

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

    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("Enter your birthday: ");
            string birsthdayStr = Console.ReadLine();
            DateTime birthday;
            int currentYear = DateTime.Now.Year;
            int yearOfBirth;
            int ageNow;
            int ageAfterTenYears;
            bool birthdayCorrectFormat = DateTime.TryParse(birsthdayStr, out birthday);
            if (birthdayCorrectFormat)
            {
                yearOfBirth = birthday.Year;
                ageNow = currentYear - yearOfBirth;
                ageAfterTenYears = ageNow + 10;
                Console.WriteLine("Your age after 10 years: {0}", ageAfterTenYears);
            }
            else
            {
                Console.WriteLine("Wrong format of birthday.");
            }
        }
    }