static void Main(string[] args)
{
Call call1 = new Call("+ 359 888 900 222", 200);
Console.WriteLine(call1.Date);
call1.PrintCallInfo(); // test of PrintCallInfo()
Console.WriteLine(call1);// works in the same way as PrintCallInfo ?!#@ maikata ..:)
}
//10 Add methods in the GSM class for adding and deleting calls
//from the calls history. Add a method to clear the call history.
public void AddCall(Call newCall)
{
this.CallHistory.Add(newCall);
}