Break in nested for loops

Question

Possible Duplicate:
How to Break from main/outer loop in a double/nested loop?

I have the following situation:

      for(int i = 0; i < schiffe.length-1; i++){
            if(schiffe[i].schaden){
                schlepper.fliege(schiffe[i].x, 
                                 schiffe[i].y, 
                                 schiffe[i].z);
                schlepper.wirdAbgeschleppt = schiffe[i];
                for(int k = 0; k < stationen.length-1; k++){
                    if(stationen[k].reparatur == null){
                        schlepper.fliege(stationen[k].x,
                                         stationen[k].y,
                                         stationen[k].z);
                        break;
                    }
                }
            }
        }

I want to

schlepper.fliege(stationen[k].x,
                 stationen[k].y,
                 stationen[k].z);

be performed once and then break out of the inner loop and continue with the for(int i... loop. So I used a break in my code. But I am not really sure if this is right. Does the break cause a break for all loops or just for the second loop?

score 46 · Accepted Answer · answered Dec 02 '10 at 06:42

It breaks only the inner loop, and therefore does what you want. To break more than one level, in Java, you can use a "labelled break" like so:

schiffe_loop:
for(int i = 0; i < schiffe.length-1; i++){
    some_stuff();
    for(int k = 0; k < stationen.length-1; k++){
        if (something_really_bad_happened()) {
            break schiffe_loop;
        }
    }
}

But usually you will not need this.

You may consider making a separate method for the inner loop anyway; it's something you can easily give a name to ("find_available_station" or something like that), and will probably need somewhere else.

Also, please be aware that your loops right now will miss the last element of each array. Think carefully about why you are using < instead of <=; it's exactly so that you use every value from 0 up to but not including the specified one.

score 6 · Answer 2 · answered Dec 02 '10 at 06:42

6

break will break the innermost loop, in your case 2nd loop.

To make it break the outer loop you can use a labeled break as:

OUTER:for(...) {
         for(...) {
            break OUTER;
         }
      }

answered Dec 02 '10 at 06:42

codaddict

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score 3 · Answer 3 · answered Dec 02 '10 at 06:38

3

break only breaks out of the innermost loop.

answered Dec 02 '10 at 06:38

Carl Norum

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score 1 · Answer 4 · answered Dec 02 '10 at 06:38

1

break will cause break for closest loop only (second loop)

answered Dec 02 '10 at 06:38

Petro Semeniuk

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score 1 · Answer 5 · answered Dec 02 '10 at 06:39

1

Just the second one. You can use "goto" of course.

answered Dec 02 '10 at 06:39

onemasse

6,514
8
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score 1 · Answer 6 · answered Dec 02 '10 at 06:40

1

Break statement terminates the closest enclosing loop or switch statement in which it appears in many languages but you can try it and be sure 100%.

answered Dec 02 '10 at 06:40

Jahan Zinedine

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score 1 · Answer 7 · answered Dec 02 '10 at 06:40

1

put the inner two loops in a function and use return to break out of both of them.

answered Dec 02 '10 at 06:40

Dan D.

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score 1 · Answer 8 · answered Dec 02 '10 at 06:40

1

If you need more control, you can use a labeled break. More info here. As others have said, break will close the closest loop.

answered Dec 02 '10 at 06:40

darioo

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score 1 · Answer 9 · answered Dec 02 '10 at 08:04

1

What about using a boolean you call 'found' and use it like this:

while(!found) {
    for(...) {
        //todo
    }
}

answered Dec 02 '10 at 08:04

KristianB

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score 0 · Answer 10 · answered Dec 02 '10 at 06:46

I Think You Can Do One More Thing..

for(int k = 0; k < stationen.length-1; k++){ if(stationen[k].reparatur == null){ schlepper.fliege(stationen[k].x, stationen[k].y, stationen[k].z);

                   k =  stationen.length + 1 ;

                }
            }

Break in nested for loops

10 Answers10