private static void Dialling(Queue <string> numbers, Smartphone smartphone, StationaryPhone stationaryPhone)
 {
     while (numbers.Count > 0)
     {
         string number = numbers.Dequeue();
         if (number.Length != 7 && number.Length != 10)
         {
             Console.WriteLine("Invalid number!");
         }
         if (number.Length == 7)
         {
             Console.WriteLine(stationaryPhone.MakeCalls(number));
         }
         if (number.Length == 10)
         {
             Console.WriteLine(smartphone.MakeCalls(number));
         }
     }
 }