public static void MainOLD()
{
var teaMaker = new TeaMaker();
var teaShop = new TeaShop(teaMaker);
teaShop.TakeOrder("Chamomile", 1);
teaShop.TakeOrder("Green tea", 2);
teaShop.TakeOrder("No milk, no sugar", 3);
teaShop.Serve();
// Serving tea to table #1
// Serving tea to table #2
// Serving tea to table #3
}
private readonly TeaMaker mTeaMaker; // readonly, defines a read only field in our application.
public TeaShop(TeaMaker teaMaker)
{
mTeaMaker = teaMaker ?? throw new ArgumentNullException("teaMaker", "teaMaker cannot be null");
// Returns value to it's left-hand operand if it isn't null; otherwise evaluates the right-hand operand and returns its result.
// Therefore, returns teaMaker as long as it isn't null.
}
