The Transaction object is responsible for reading the transaction file, finding the relevant account in the array of customers and applying the transaction. To find the relevant account a matching function within the Customer class can be used. A transaction can be applied by calling a function within the Customer class which in turn calls a function in the savingsAccount class. See UML modelling above. You may choose to alter the function specifications if required. As indicated above Customer objects provide the access to the accounts including searching.
The savingsAccount objects provide basic operations such as deposit, withdrawal, adding interest, getting a balance and account number matching.
Typical data to be found in the file is as follows:
A transaction record is in three parts, firstly an account number, secondly an amount and thirdly a transaction code (C = credit, D = debit, I = add interest). Assume all transactions are valid i.e. generate no errors.