private void BeHappy(object item)
{
IEmotional emotional = item as IEmotional; // conditional down casting
if (emotional != null)
{
Console.Write($"{item.GetType().Name}: ");
emotional.BeHappy();
}
}
private void BeHappy(object obj)
{
IEmotional emotional = obj as IEmotional;
if (emotional != null)
{
Console.WriteLine("{0}", obj.GetType().Name);
emotional.BeHappy();
}
}