예외처리 try catch when

using System;

class Program
{
    class FilterableException : Exception
    {
        public int ErrorNo { get; set; }  
    }
      
    static void Main(string[] args)
    {
        Console.WriteLine("Enter Number Between 0~10");
        string input = Console.ReadLine();
        try
        {
            int num = Int32.Parse(input);

            if (num < 0 || num > 10)
                throw new FilterableException() { ErrorNo = num };
            else
                Console.WriteLine($"Output : {num}");
        }
        catch (FilterableException e) when (e.ErrorNo < 0)    //when 필터링
        {
            Console.WriteLine("Negative input is not allowed.");
        }
        catch (FilterableException e) when (e.ErrorNo > 10)
        {
            Console.WriteLine("Too big number is not allowed.");
        }
    }



}