In CheckingAccount, in applyForCreditCard, there was an unused parameter
relating to the Speculative Generality bad smell. There were also fields
in this class named fSavingsAccount and fDebitCard.

In CheckingAccount and in Bank, there was a method named
applyForCreditCard that referred to the feature envy bad smell. I moved
applyForCreditCard to the Bank class, since it seemed to belong there.