using System.Xml.Linq;

internal class Program
{
    static bool DataValidationLengthCheck(int intValue) // Validation For Age
    {
        if (intValue <= 100) // Put  age 100 as the limit for this program
            return true; //If age below 100 you have picked the correct age limit
        else
            return false; // If age over 100 the program say incorrect meaning you are over the age limit
    }

    private static void Main(string[] args)
    {
        // Data Validation For Surname

        string Surname = "";

        while (true)
        {
            Console.WriteLine("Hi there what is your surname?"); //Prompt to user asking their Surname
            Surname = Console.ReadLine();//Input for user to enter the surname

            // Data Validation
            if (Surname == "")
            {
                Console.WriteLine("Validation Error!");
                Console.WriteLine("Presence Check Fail!");
            }
            else if (Surname.Length < 2)
            {
                Console.WriteLine("Length Check Fail");
                Console.WriteLine("Please Input Correctly!");
            }
            else
            {
                break;
            }
        }

        Console.WriteLine("Hi there Mr " + Surname); //Output the line for the user with surname included

        int age = 0;

        while (true)
        {
            Console.WriteLine("Please enter your age");

            while (true)
            {
                try
                {
                    age = Convert.ToInt16(Console.ReadLine());
                    break;
                }
                catch
                {
                    Console.WriteLine("Error");
                }
            }

            if (DataValidationLengthCheck(age))
            {
                Console.WriteLine("Correct");
                break;
            }
            else
            {
                Console.WriteLine("Enter Your Age Correctly");
            }
        }

        Console.WriteLine("Can you tell please enter your National Insurance Number");

        string National = "";

        while (true)
        {
            Console.WriteLine("Can you input your first two given letters?");
            National = Console.ReadLine();

            //Data Validation

            if (National == "")
            {
                Console.WriteLine("Validation Error!");
                Console.WriteLine("Presence Check Fail!");
            }
            else if (National.Length < 2)
            {
                Console.WriteLine("Length Check Fail");
                Console.WriteLine("Please Input Correctly!");
            }
            else
            {
                break;

            }

        }


        string NationalNumb = "";

        while (true)
        {
            Console.WriteLine("Can you input you next 6 digit characters from your National Insurance Number ?");
            NationalNumb = Console.ReadLine();

            //Data Validation

            if(NationalNumb =="")
            {
                Console.WriteLine("Validation Error!");
                Console.WriteLine("Presence Check Fail!");
            }
            else if (NationalNumb.Length < 6) 
            {
                Console.WriteLine("Length Check Fail");
                Console.WriteLine("Please Input Correctly!");
            }
            else
            { 
                break; 
            
            }

        }

        Console.WriteLine("Now enter the last and final character on your National Insurance Number ");
        string NationalChar = Console.ReadLine();

        Console.WriteLine("Your National Insurance Number is " + National + NationalNumb + NationalChar);



        Console.ReadKey();

    }
}