How do I break out of nested loops in Java?

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梦毁少年i
梦毁少年i 2020-11-21 11:51

I\'ve got a nested loop construct like this:

for (Type type : types) {
    for (Type t : types2) {
         if (some condition) {
             // Do somethin         


        
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  • 2020-11-21 12:11

    Even creating a flag for the outer loop and checking that after each execution of the inner loop can be the answer.

    Like this:

    for (Type type : types) {
        boolean flag=false;
        for (Type t : types2) {
            if (some condition) {
                // Do something and break...
                flag=true;
                break; // Breaks out of the inner loop
            }
        }
        if(flag)
            break;
    }
    
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  • 2020-11-21 12:12

    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;
                }
            }
        }
    }
    
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  • 2020-11-21 12:13
    boolean broken = false; // declared outside of the loop for efficiency
    for (Type type : types) {
        for (Type t : types2) {
            if (some condition) {
                broken = true;
                break;
            }
        }
    
        if (broken) {
            break;
        }
    }
    
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  • 2020-11-21 12:14

    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;
            }
        }
    }
    
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  • 2020-11-21 12:15

    You can use labels:

    label1: 
    for (int i = 0;;) {
        for (int g = 0;;) {
          break label1;
        }
    }
    
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  • 2020-11-21 12:15

    You can break from all loops without using any label: and flags.

    It's just tricky solution.

    Here condition1 is the condition which is used to break from loop K and J. And condition2 is the condition which is used to break from loop K , J and I.

    For example:

    public class BreakTesting {
        public static void main(String[] args) {
            for (int i = 0; i < 9; i++) {
                for (int j = 0; j < 9; j++) {
                    for (int k = 0; k < 9; k++) {
                        if (condition1) {
                            System.out.println("Breaking from Loop K and J");
                            k = 9;
                            j = 9;
                        }
                        if (condition2) {
                            System.out.println("Breaking from Loop K, J and I");
                            k = 9;
                            j = 9;
                            i = 9;
                        }
                    }
                }
            }
            System.out.println("End of I , J , K");
        }
    }
    
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