System.FormatException in C#

Question

I keep getting a FormatException in each of the cases on the line where I try to assign the value for the sale variable. Anyone know what I am doing wrong? I am supposed to make this console program as homework to learn about loops, but I am finding out more about other things. It is supposed to keep a running tab of salesperson's commission based a a 10% commission of each sale. Anyways, here is the code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace TubSales
{
   class Program
   {
      static void Main(string[] args)
      {
         char initial;
         const double COMM_INT = 0.10;
         double sale, aComm = 0, bComm = 0, eComm = 0;
         Console.Write("Enter 'A' for Andrea, 'B' for Brittany,\n'E' for Eric, or 'Z' to quit >> ");
         initial = Convert.ToChar(Console.Read());
         while (initial != 'z' && initial != 'Z')
         {
            switch (initial)
            {
               case 'a':
               case 'A':
                  Console.Write("Enter the sales for Andrea >> ");
                  sale = Convert.ToDouble(Console.ReadLine());
                  aComm = aComm + COMM_INT * sale;
                  break;
               case 'b':
               case 'B':
                  Console.Write("Enter the sales for Brittany >> ");
                  sale = Convert.ToDouble(Console.ReadLine());
                  bComm = bComm + COMM_INT * sale;
                  break;
               case 'e':
               case 'E':
                  Console.Write("Enter the sales for Eric >> ");
                  sale = Convert.ToDouble(Console.ReadLine());
                  eComm = eComm + COMM_INT * sale;
                  break;
               default:
                  Console.WriteLine("You did not enter a valid initial");
                  break;
            }
            Console.Write("Enter 'A' for Andrea, 'B' for Brittany, or 'E' for Eric >> ");
            initial = (char)Console.Read();
         }
         Console.WriteLine("Andrea had {0}, Brittany had {1}, and Eric had {2} in commissions.", aComm.ToString("C"), bComm.ToString("C"), eComm.ToString("C"));
         Console.Write("Press any key to exit... ");
         Console.ReadKey();
      }
   }
}

Answer 1

While Reed's answers is great, it's not the problem here.

What really happens is the same situation as this one

Console.Read only read the "Second part of the carriage return" and returns "". This is why the Convert fails.

replace

initial = Convert.ToChar(Console.Read());

with

initial = Convert.ToChar(Console.ReadLine());