Write a C# Sharp program to check whether an alphabet is a vowel or consonant

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
 
public   class exercise16
   {
       static void Main(string[] args)
       {
           char ch;
           Console.Write("\n\n");
           Console.Write("check whether the input alphabet is a vowel or not:\n");
           Console.Write("-----------------------------------------------------");
           Console.Write("\n\n");

           Console.Write("Input an Alphabet (A-Z or a-z) : ");
           ch = Convert.ToChar(Console.ReadLine().ToLower());
           int i=ch;
           if(i>=48 && i<=57)
           {
            Console.Write("You entered a number, Please enter an alpahbet."); 
            }
           else
           {		   
           switch (ch)
           {
                case 'a':
                   Console.WriteLine("The Alphabet is vowel");
                   break;
               case 'i':
                   Console.WriteLine("The Alphabet is vowel");
                    break;
               case 'o':
                   Console.WriteLine("The Alphabet is vowel");
                   break;
               case 'u':
                   Console.WriteLine("The Alphabet is vowel");
                   break;
               case 'e':
                   Console.WriteLine("The Alphabet is vowel");
                   break;
               default:
                   Console.WriteLine("The Alphabet is not a vowel");
                   break;
            }
			}
           Console.ReadKey();
       }
   }