ArrayLists

The Aims

In this exercise, you will convert the code that uses an array into an ArrayList.

Creating an ArrayList

Using the TestAccount2 class:

1. Create a new ArrayList to replace the array called accounts.

2. Change each of the lines that adds an account into the array to instead add an account into the arraylist.

3. Modify the loop and all other code in the class, so that the class compiles.

Click here to see the sample solution

import java.util.ArrayList;
import java.util.List;

public class TestAccount2 {
    public static void main(String[] args) {
        List<Account> accounts = new ArrayList<>();

        try {
            accounts.add(new Account(1000.0, "Fingers", AccountType.CHECKING));
        } catch (DodgyNameException e) {
            System.out.println(e.getMessage());
        }

        try {
            accounts.add(new Account(2000.0, "Bob", AccountType.CHECKING));   
        } catch (DodgyNameException e) {
            System.out.println(e.getMessage());
        }

         try {
            accounts.add(new Account(1500.0, "Charlie", AccountType.SAVING));
        } catch (DodgyNameException e) {
            System.out.println(e.getMessage());
        }
         try {
            accounts.add(new Account(1500.0, "Charlie", AccountType.SAVING));
        } catch (DodgyNameException e) {
            System.out.println(e.getMessage());
        }
        try {
            accounts.add(new Account(2500.0, "Eve", AccountType.CREDIT_CARD));
        } catch (DodgyNameException e) {
            System.out.println(e.getMessage());
        }

        Account.setInterestRate(0.07);

        for (int i = 1; i < accounts.size(); i++) {
            System.out.println("Account: " + accounts.get(i));
            accounts.get(i).addInterest();
            System.out.println("Balance after interest: " + accounts.get(i).getBalance());
            System.out.println();
        }

        System.out.println(accounts.get(2).equals(accounts.get(3)) ? "account 2 and 3 are equal" : "account 2 and 3 are not equal"); 
        System.out.println(accounts.get(2).equals(accounts.get(4)) ? "account 2 and 4 are equal" : "account 2 and 4 are not equal"); 

        accounts.get(0).withdraw(100); 
        accounts.get(1).withdraw(); 
        accounts.get(2).withdraw(2500);
    }
}