break and continue statement in if, table 2.5, page 91 (Java OCA 8 Programmer I Study Guide)

[Matt Road]

Hi all,

I am writing regarding pag 91. The table 2.5 states that IF loop doesn't allow both break and continue statement even if in the pages before there many example where break and continue are used inside an IF loop. Can you please help me ?

Thank you!

[Paweł Baczyński]

The if statement is not a loop.

Actually, you can break out of an if.

public static void main(String[] args) {
    int value = 2;
    label:
    if (value > 1) {
        if (value <=2 ) {
            break label;
        }
        System.out.println("More than two");
    }
    System.out.println("Done");
}

This prints:
Done

This doesn't compile (and if it did compile it would be broken anyway...)

public static void main(String[] args) {
    int value = 2;
    if (value > 1) {
        if (value <=2 ) {
            break;
        }
        System.out.println("More than two");
    }
    System.out.println("Done");
}

[Matt Road]

so it means that break and continue in the IF are only allowed if a label is provided ? Thank you!

[Paweł Baczyński]

No, continue is not allowed, even with a label.

[Matt Road]

So I should correct the first line of this table : Break statement YES allowed (when LABEL is provided ) ... Am I right ? Thank you!

[Roel De Nijs]

Matt Road wrote:So I should correct the first line of this table : Break statement YES allowed (when LABEL is provided ) ... Am I right ?

The first line of table 2.5 should be

       optional labels    break statement     continue statement
if     Yes*               Only if labeled     No

If you check this page of Oracle's Java tutorial about branching statements, it's not mentioned that a labeled break statement can be used together with an if statement. It's only discussing the different loops and the switch statement.

Hope it helps!
Kind regards,
Roel

[Jeanne Boyarsky]

Matt,
Thanks for noticing this! I've added it to our errata list and credited you. I have a different fix than Roel's though. I'd go with renaming the table header to be allows unlabeled break statements.

[Esbjörn Rundberg]

Paweł Baczyński wrote:No, continue is not allowed, even with a label.

Hi Pawel!

Question 18 in the same chapter uses a continue with a label in an if statement and it appear to work. Am I missing something?

public class Loop {
  public static void main (String [] args) 
  {
    int count = 0;
    ROW_LOOP: for(int row = 1; row <= 3; row++)
      for(int col = 1; col <= 2; col++) {
        if(row * col % 2 == 0) continue ROW_LOOP;
        count++;
      }
      System.out.print(count);
  }
}

[Roel De Nijs]

Hi Esbjörn Rundberg,

First of all, a warm welcome to CodeRanch!

Esbjörn Rundberg wrote:Question 18 in the same chapter uses a continue with a label in an if statement and it appear to work. Am I missing something?

Yes, you are definitely missing something Yhe continue statement is inside a loop. Just remove both for loops and see what happens...

Hope it helps!
Kind regards,
Roel

[Esbjörn Rundberg]

Thank you. Now I see, I wasn't paying enough attention when reading the thread.

[Roel De Nijs]

Esbjörn Rundberg wrote:Now I see, I wasn't paying enough attention when reading the thread.

So you already discovered an area which you must improve for the actual exam If you don't pay enough attention to the question, code snippet and possible answers; it's almost impossible to answer the question correctly (unless you are very lucky).