Question

This is very interesting, i notice. Before i can explain further its best i show the code and you will understand what i mean.

This is the code:

public class Qn3 {
    static BigDecimal[] accbal = new BigDecimal[19];
    private static Integer[] accnums = new Integer[19];

    public static void main(String[] args) {
        addaccount();

    }
    public static void addAccount() {

        int i = 0, accno, input, j, check;
        BigDecimal accbala;
        DecimalFormat df = new DecimalFormat("0.00");

        Scanner sc = new Scanner(System.in);
        Scanner in = new Scanner(System.in);
        accnums[1] = new Integer(1);

        while (accnums.length >= count(accnums)) {
            System.out.print("Enter the account number: ");
            while (sc.hasNext("[0-9]{7}")) {
                accno = sc.nextInt();
                System.out.print("Enter account balance: ");
                accbala = in.nextBigDecimal();

                for (j = 0; j < accnums.length; j++) {
                    if (accnums[j] == null)
                        break;
                    else if (accnums[j].equals(accno)) {
                        break;
                    }
                }

                if (j == accnums.length) {
                    System.out.print("No more than 20 accounts can be added.");
                } else if (accnums[j] != null) {
                    if ((accnums[j].equals(accno)))
                        System.out.println("Account already exists");
                    break;
                } else {
                    accnums[j] = accno;
                    accbala = accbala.setScale(2, RoundingMode.HALF_UP);
                    accbal[j] = accbala;
                    check = j;
                    System.out.println("Current number of accounts in the system: "
                                    + (check + 1)
                                    + "\nNumber of accounts still can be added: "
                                    + (20 - (check + 1)));

                }
            }

            while (!sc.hasNext("[0-9]{7}")) {
                System.out.println("Wrong NRIC");
                break;
            }
            while (accnums.length <= count(accnums)) {
                System.out.println("20 accounts have already been created");
                break;
            }
            break;
        }
    }

    private static int count(Integer[] array) {
        int count = 0;
        // accnums = new Integer[] {1,2};
        for (int index = 0; index < array.length; index++) {
            if (array[index] != null) {
                count++;
            }
        }
        // System.out.println("You have used " + count + " slots");
        return count;
    }
}

So now that you have seen the code the problem that is hard to notice is this, take note of the line in the addaccount() method where

 System.out.println("Current number of accounts in the system: "+(check+1)+"\nNumber of accounts still can be added: "+(20 - (check+1)));

this line the first check+1 will give me 1 then the next one gives me 3! and then the next time i run the method it gives me 4 and then again 5 and so on so forth, what is happening to 2?

Answer 1

You have that println in an else block, and when j == 1 you’re hitting the else if case. Try removing this line

accnums[1] = new Integer (1);