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5. Objects and Classes (2)

Lab Exercise 5-2: Use Arrays to Represent Associations


In this exercise you will use arrays to implement the multiplicity on the association between a bank and its customers.

The UML Model of the banking Package


To the banking package, you will add the Bank class as modeled by the UML diagram above. A bank object simply keeps track of an association between itself and its customers. We will implement this aggregate association with an array of Customer objects. We will also need to keep a integer attribute that keeps track of how many customers currently exist in the bank.

  1. Create the banking directory. Copy the previous Banking project files in this package directory.
  2. Add two attributes to the Bank class: customers (an array of Customer objects) and numberOfCustomers (an integer that keeps track of the next customers array index).
  3. Add a public constructor that initializes the customers array with some appropriate maximum size (at least bigger than 5).
  4. Add the addCustomer method. This method must construct a new Customer object from the parameters (first name, last name) and place it on the customers array. It must also increment the numberOfCustomers attribute.
  5. Add the getNumOfCustomers accessor method, which returns the numberOfCustomers attribute.
  6. Add the getCustomer method. This method returns the customer associated with the given index parameter.
  7. Compile and run the TestBanking program. You shoud see the following output:
    Customer [1] is Simms, Jane
    Customer [2] is Bryant, Owen
    Customer [3] is Soley, Tim
    Customer [4] is Soley, Maria