using a String variable to access an object in a class

Question

I am fairly new to JAVA, but I am working on a program and this is the issue im running into, might be a simple fix.

I prompt the user to enter their ID for a mock ATM system.

            {
            System.out.println("Enter an ID: ");
            Scanner input = new Scanner(System.in);
            String acctID = input.next();
            withdrawAccount(acctID);
            System.out.println(IDnum.getBalance());
            }

There is more to the code but it is irrelevant at this time. There will be several if statements to see what action the user wants to do, i.e. withdraw money from their account. In this program I want to have the user enter there ID and save it as a string and pass it to WithdrawAccount method. So acctID would reference what ever the user enters for the account ID. Note the account ID is the same as the name of the Account variable. so Account 0 will have an ID of 0.

    public static void withdrawAccount(String acctID)
            {
            System.out.println("Enter Withdraw Amount: ");
            Scanner input = new Scanner(System.in);
            double WithdrawAmount = input.nextDouble();
            acctID.setBalance(acctID.getBalance() - WithdrawAmount);
            }

@dnault I want to have the user enter there ID and save it as a string and pass it to WithdrawAccount method. — Luiggi Mendoza
– Luiggi Mendoza, Commented Nov 19, 2012 at 22:16
You should pass an Account (or the class you have) object which account id is the String the user typed. This looks more like a design issue. — Luiggi Mendoza
– Luiggi Mendoza, Commented Nov 19, 2012 at 22:17
I want the user to enter an ID and i want to send it to each method, so if the user enters 43, String id = input.next(); now i want to use the String "id" to access Account 43 that is already stored under the Account Objects. — Kevin Zaki
– Kevin Zaki, Commented Nov 19, 2012 at 22:30

JB Nizet · Accepted Answer · 2012-11-19 22:54:14Z

1

If I understand your question correctly, you want to associate String IDs with accounts identified by these IDs. One way to do that is to use a Map:

private Map<String, Account> accountsById = new HashMap<String, Account>();

...

accountsById.put("1", account1);
accountsById.put("2", account2);
accountsById.put("3", account3);
...

And then to get the account with a given ID:

Account account = accountsById.get(idEnteredByTheUser);

edited Nov 19, 2012 at 22:54

answered Nov 19, 2012 at 22:36

JB Nizet

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Wald · Accepted Answer · 2012-11-19 22:42:47Z

0

Probably storing them into an ArrayList or Map would best to save them.

And when you are calling the withdraw method you will need to pass the whole 'Account' instead of a string so you can edit exactly their balance with the 'setBalance' method of the class.

answered Nov 19, 2012 at 22:42

Wald

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