编辑代码

using System;

class HelloWorld
{
    static void checkAge(int age)
    {
        if(age < 18)
        {
            throw new ArithmeticException("Access denied - You must be at least 18 years old.");
        }
        
        else
        {
            Console.WriteLine("Access granted - You are old enough!");
        }
    }

    static void Main(string[] args)
    {
        string age = Console.ReadLine();
        checkAge(int.Parse(age));
    }
}