public static void CallsInfo(GSM gsm)
 {
     foreach (var call in gsm.CallHistory)
     {
         Console.WriteLine("*****New call*****");
         Console.WriteLine(call);
     }
 }
 public static void AddCalls(GSM gsm)
 {
     gsm.AddCall(new Call("0882323436", 74));
     gsm.AddCall(new Call("0882323436", 7324));
     gsm.AddCall(new Call("0882323436", 7344));
     gsm.AddCall(new Call("0882323436", 123474));
     gsm.AddCall(new Call("0882323436", 174));
     gsm.AddCall(new Call("0882323436", 574));
 }
        public static void RemoveLongestCall(GSM gsm)
        {
            const int start = 0;

            long longestCall = start;
            int  index       = start;

            for (int i = start; i < gsm.CallHistory.Count; i++)
            {
                if (gsm.CallHistory[i].Duration > longestCall)
                {
                    longestCall = gsm.CallHistory[i].Duration;
                    index       = i;
                }
            }
            gsm.DeleteCall(index);
        }
 public static void PrintTotalPrice(GSM gsm, double price)
 {
     Console.WriteLine("Total price is: {0}", gsm.Price);
 }