How to break out of nested loops in Java?

Technically the correct answer is to label the outer loop. In practice if you want to exit at any point inside an inner loop then you would be better off externalizing the code into a method (a static method if needs be) and then call it.

That would pay off for readability.

The code would become something like that:

private static String search(...) 
{
    for (Type type : types) {
        for (Type t : types2) {
            if (some condition) {
                // Do something and break...
                return search;
            }
        }
    }
    return null; 
}

Matching the example for the accepted answer:

 public class Test {
    public static void main(String[] args) {
        loop();
        System.out.println("Done");
    }

    public static void loop() {
        for (int i = 0; i < 5; i++) {
            for (int j = 0; j < 5; j++) {
                if (i * j > 6) {
                    System.out.println("Breaking");
                    return;
                }
                System.out.println(i + " " + j);
            }
        }
    }
}

How to break out of nested loops in Java?

 I’d definitely prefer to put the loops in a different method, at which point you can just return to stop iterating completely. This answer just shows how the requirements in the question can be met.

You can use break with a label for the outer loop. For example:

public class Test {
    public static void main(String[] args) {
        outerloop:
        for (int i=0; i < 5; i++) {
            for (int j=0; j < 5; j++) {
                if (i * j > 6) {
                    System.out.println("Breaking");
                    break outerloop;
                }
                System.out.println(i + " " + j);
            }
        }
        System.out.println("Done");
    }
}

This prints:

0 0
0 1
0 2
0 3
0 4
1 0
1 1
1 2
1 3
1 4
2 0
2 1
2 2
2 3
Breaking
Done

Answer #3:

You can use a named block around the loops:

search: {
    for (Type type : types) {
        for (Type t : types2) {
            if (some condition) {
                // Do something and break...
                break search;
            }
        }
    }
}

How to break out of nested loops in Java without labels?

I never use labels. It seems like a bad practice to get into. Here’s what I would do:

boolean finished = false;
for (int i = 0; i < 5 && !finished; i++) {
    for (int j = 0; j < 5; j++) {
        if (i * j > 6) {
            finished = true;
            break;
        }
    }
}

Answer #4:

You can use labels:

label1: 
for (int i = 0;;) {
    for (int g = 0;;) {
      break label1;
    }
}

How to break out of nested loops in Java using function?

Use a function:

public void doSomething(List<Type> types, List<Type> types2){
  for(Type t1 : types){
    for (Type t : types2) {
      if (some condition) {
         // Do something and return...
         return;
      }
    }
  }
}

Answer #6:

You can use a temporary variable:

boolean outerBreak = false;
for (Type type : types) {
   if(outerBreak) break;
    for (Type t : types2) {
         if (some condition) {
             // Do something and break...
             outerBreak = true;
             break; // Breaks out of the inner loop
         }
    }
}

Depending on your function, you can also exit/return from the inner loop:

for (Type type : types) {
    for (Type t : types2) {
         if (some condition) {
             // Do something and break...
             return;
         }
    }
}

Answer #7:

If you don’t like breaks and gotos, you can use a “traditional” for loop instead the for-in, with an extra abort condition:

int a, b;
bool abort = false;
for (a = 0; a < 10 && !abort; a++) {
    for (b = 0; b < 10 && !abort; b++) {
        if (condition) {
            doSomeThing();
            abort = true;
        }
    }
}

Answer #8:

I needed to do a similar thing, but I chose not to use the enhanced for loop to do it.

int s = type.size();
for (int i = 0; i < s; i++) {
    for (int j = 0; j < t.size(); j++) {
        if (condition) {
            // do stuff after which you want 
            // to completely break out of both loops
            s = 0; // enables the _main_ loop to terminate
            break;
        }
    }
}

How to break out of nested loops in Java?

Using ‘break’ keyword alone is not the appropriate way when you need to exit from more than one loops. You can exit from immediate loop No matter with how many loops your statement is surrounded with. You can use ‘break’ with a label! Here I’ve used the label “abc” You can write your code as following, within any function in Java

This code shows how to exit from the most outer loop

 abc: 
    for (int i = 0; i < 10; i++) { 
        for (int j = 0; j < 10; j++) { 
           for (int k = 0; k < 10; k++) { 
              if (k == 1){
                 break abc;
              } 
        } 
    } 
}

Also you can use break statement to exit from any loop in a nested loop.

    for (int i = 0; i < 10; i++) { 
       abc:for (int j = 0; j < 10; j++) { 
           for (int k = 0; k < 10; k++) { 
              if (k == 1){
                 break abc;
              } 
        } 
    } 
}

The following code shows an example of exiting from the innermost loop. In other works,after executing the following code, you are at the outside of the loop of ‘k’ variables and still inside the loop of ‘j’ and ‘i’ variables.

    for (int i = 0; i < 10; i++) { 
        for (int j = 0; j < 10; j++) { 
           for (int k = 0; k < 10; k++) { 
              if (k == 1){
                 break;
              } 
        } 
    } 
}

Hope you learned something from this post.

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