using System;
class Break
{
    static void Main()
    {
        char Letter;
        switch (Letter)
        {
            case 'a':
                Console.WriteLine("vowel");
                break;
            case 'e':
                Console.WriteLine("vowel");
                break;
            case 'i':
                Console.WriteLine("vowel");
                break;
            case 'o':
                Console.WriteLine("vowel");
                break;
            case 'u':
                Console.WriteLine("vowel");
                break;
            case 'e':
                Console.WriteLine("vowel");
                break;
            default:
                Console.WriteLine("not a vowel");
                break;
        }
    }
}


error - use of unassigned local variable letter