public static void MainFunction()
{
IMessageWriter writer = new ConsoleMessageWriter();
var salutation = new Salutation(writer);
salutation.Exclaim();
}
public static void MainFunction()
{
var typeName = ConfigurationManager.AppSettings["messageWriter"];
var type = Type.GetType(typeName, false);
IMessageWriter writer = (IMessageWriter)Activator.CreateInstance(type);
var salutation = new Salutation(writer);
salutation.Exclaim();
}