Do-While loop not operating properly in Java

Question

So this should continue to loop until user hits "ENTER" or the array is filled. But after entering the first element in the array it quits the loop.

do 
{
    System.out.print("Enter name (or <ENTER> if done): ");
    names[index] = kb.nextLine();
    if(! (names[index].equals(""))) 
    {

        System.out.print("Enter phone number: ");
        phone[index] = kb.nextLine();

        System.out.print("Enter email address: ");
        email[index] = kb.nextLine();

        index++;
        break;
    }
} while ( ! (names[index - 1].equals("")) && index < SIZE);

Corrected

do
{
        System.out.print("Enter name (or <ENTER> if done): ");
        names[index] = kb.nextLine();

        if(! (names[index].equals("")))
            {

            System.out.print("Enter phone number: ");
            phone[index] = kb.nextLine();

            System.out.print("Enter email address: ");
            email[index] = kb.nextLine();

            }   
        index++;

    } while ( ! (names[index - 1].equals("")) && index < SIZE);

PurkkaKoodari · Accepted Answer · 2013-11-14 19:42:24Z

5

This is very simple. break; exits the loop. Remove it.

EDIT: Also, in your condition of the loop you use [index - 1]. Now, if your input is empty (user pressed Enter) the index won't be incremented and it will point to the previous item. Change it to just [index] and it'll work.

edited Nov 14, 2013 at 19:42

answered Nov 14, 2013 at 19:32

PurkkaKoodari

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4 Comments

bblincoe Over a year ago

+1 break does not exit from an if statement. It will exit from the nearest loop. While you're at it, here is some literature about a break bug: users.csc.calpoly.edu/~jdalbey/SWE/Papers/att_collapse.html

user2993639 Over a year ago

When I remove the break, now the loop won't exit when I hit enter

user2993639 Over a year ago

Got it. Moved the index++ outside the if statement, so that it is now incremented if I hit enter.

PurkkaKoodari Over a year ago

@user2993639 Yes, that is another way to do it.

knordbo · Accepted Answer · 2013-11-14 19:39:53Z

0

The problem is the break and if-statement. Working example:

do {
    System.out.print("Enter name (or <ENTER> if done): ");
    names[index] = kb.nextLine();

    if (names[index].equals(""))
        break;

    System.out.print("Enter phone number: ");
    phone[index] = kb.nextLine();

    System.out.print("Enter email address: ");
    email[index] = kb.nextLine();

    index++;

} while (index < SIZE);

answered Nov 14, 2013 at 19:39

knordbo

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1 Comment

user2993639 Over a year ago

Removed the break, but now the loop won't exit when I hit enter

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