C#

aaffbbww wrote:

Then how would I implement it... ?

aaffbbww wrote:

would I completely rework the code?

class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine(
            "This strange program won't let you type the letter 'b', systematically replacing it with 'ß' instead, "
            + "even though German has the letter 'b' also. Type away, and type 'exit' to quit. Do it now; this "
            + "really is pretty useless.\r\n\r\n");

        string s;
        while ((s = prompt("Input>")).ToLower() != "exit")
        {
            Console.WriteLine("Fantastic, you wrote: {0}\r\n", s);
            Console.WriteLine();
        }
    }

    
    static string prompt(string lead, params object[] args)
    {
        if (args.Length > 0)
            lead = string.Format(lead, args);

        Console.Write(lead);

        var input = new StringBuilder();
        
        while (true)
        {
            var key = Console.ReadKey();
            char c = key.KeyChar.ToString().ToLower()[0];

            if (c == '\r')
                break;

            switch (c)
            {
                case 'b':
                    c = 'ß';
                    break;

                default:
                    c = key.KeyChar;
                    break;
            }

            input.Append(c);
            Console.Write(c);
        }
        Console.WriteLine();
        return input.ToString();
    }
}