private void but_Bill_Click(object sender, EventArgs e)
{
//checkout mode
mode = eMode.eCheckout;
//clear tea and waiter
tea_status = eTea.eClear;
waiter_status = eWaiter.eClear;
teaWaiterStatusCheck();
DialogResult result= MessageBox.Show(this,"The system is now in checkout mode. To exist checkout mode, press OK.", "Checkout Mode");
if (result == DialogResult.OK)
{
mode = eMode.eOperational;
}
}