public void If_Customer_has_credit(Customer customer, Action has_credit, Action has_no_credit)
{
if(customer.Balance >= 1000.0) {
has_credit();
} else {
has_no_credit();
}
}
public void Checkout(Customer customer)
{
If_Customer_has_credit(customer,
Checkout_with_credit_card,
Checkout_with_cash);
}