Your code has endless loop. The problem causes by this block:
while (letter != quit)
{
}
If
letter
is not equal to
quit
, then this loop will never end.
You need to provide a function for user to modify
letter
and pause the loop before a new loop.
while (letter != quit)
{
Console.Clear();
Console.WriteLine("what is your initial? Enter Z to quit");
letter = Convert.ToChar(Console.ReadLine());
switch(letter)
{
case ....
case ....
case ....
default ....
}
Console.WriteLine("bla bla bla...");
Console.ReadKey();
}