AgeNowAndAfter

using System;

class AgeNowAndAfter
{
    static void Main(string[] args)
    {
        int year = 0, month = 0, day = 0;

        //get the current date values
        DateTime today = DateTime.Today;

        //initialize the birthday values in the corresponding inteher variables
        for (int cnt = 0; cnt < 3; cnt++)
        {
            bool check = false;
            switch (cnt)
            {
                case 0:
                    Console.WriteLine("Enter your year of birth here /ex. 2014/: ");
                    check = int.TryParse(Console.ReadLine(), out year);
                    if (!check || year < 1900 || year > today.Year)
                    {
                        cnt--;
                        Console.Clear();
                        Console.WriteLine("Invalid Input. Try Again.");
                    }
                    break;
                case 1:
                    Console.WriteLine("Enter your month of birth here /ex. 9/: ");
                    check = int.TryParse(Console.ReadLine(), out month);
                    if (!check || month < 1 || month > 12)
                    {
                        cnt--;
                        Console.Clear();
                        Console.WriteLine("Invalid Input. Try Again.");
                    }
                    break;

                //checking the max day value of the chosen month and alarm or initialise
                case 2:
                    Console.WriteLine("Enter your day of birth here /ex. 13/: ");
                    check = int.TryParse(Console.ReadLine(), out day);
                    if (!check || day < 0 || day > DateTime.DaysInMonth(year, month))
                    {
                        cnt--;
                        Console.Clear();
                        int maxDays = DateTime.DaysInMonth(year, month);
                        Console.WriteLine(day > maxDays ? "Invalid Input. This Month Only Has {0} days." :
                 "Invalid Input. Try Again.", maxDays);
                    }
                    break;
                default:
                    Console.WriteLine("Something went wrong here.");
                    break;
            }
        }
        //The date of birth from the u.input
        DateTime birthday = new DateTime(year, month, day);
        int age = today.Year - birthday.Year;

        /*check if the value of age added to the birthday
         date gives result bigger than today's date and correct
         the result according to the month and day of birth and current ones. */
        if (today < birthday.AddYears(age))
        {
            age--;
        }
        //display the result and hold the console open
        Console.WriteLine("Your age is {0} and after ten years, you'll be {1}.", age, age + 10);
        Console.ReadLine();
    }
}