CODEWITHSUNDEEP
javafor-looprecursionreturn
Darshana
Darshana

Reputation: 2548

recursive method inside loop

I want to write a code like this

public int recursiveMethod() {
    for (int i = 0; i < 10; i++) {
        if (someBool) {
            return recursiveMethod();
        } else {
            return -1;
        }
    }
}

but this gives compile error missing return statement. Is there other way I can achieve this.

UPDATE : actual code

public static File searchFile(File currentFile) {
    File[] results = null;

    if (currentFile.isDirectory()) {
        for (File file : currentFile.listFiles()) {
            if (file.isDirectory()) {
                return searchFile(file);
            } else {
                results = file.getParentFile().listFiles(new FilenameFilter() {
                    public boolean accept(File dir, String name) {
                        return name.toLowerCase().endsWith(".sh");
                    }
                });

                if (results.length > 0) {
                    return results[0];
                } else {
                    return null;
                }
            }
        }
    } else {
        results = currentFile.getParentFile().listFiles(new FilenameFilter() {
            public boolean accept(File dir, String name) {
                return name.toLowerCase().endsWith(".sh");
            }
        });

        if (results.length > 0) {
            return results[0];
        } else {
            return null;
        }
    }
}

Upvotes: 0

Views: 340

Answers (2)

Jon Skeet
Jon Skeet

Reputation: 1504062

Your code is broken in the way it's looping - you're stopping on the very first iteration, either reporting success or failure. You should be continuing to loop until you find something or run out of items to iterate over.

I would change the general structure so that the last statement in the method is return null; - so any time you can return a positive result, you do so, but otherwise you just let it fall through. So something like this:

public static File searchFile(File currentFile) {
    if (!currentFile.isDirectory()) {
        throw new InvalidArgumentException("Starting point must be a directory");
    }
    for (File file : currentFile.listFiles()) {
        if (file.isDirectory()) {
            File result = searchFile(file);
            if (result != null) {
                return result;
            }
        } else if (file.getName().toLowerCase().endsWith(".sh")) {
            return file;
        }
    }
    // Not found anything: return null to indicate failure (in this branch)
    return null;
}

(I've removed the call to getParentFile() and restructured the code for simplicity. Now it will only accept a directory as the starting point, but that simplifies things greatly, and makes much more sense anyway, IMO.)

Upvotes: 3

Ashish
Ashish

Reputation: 520

what is someBool? You are calling recursiveMethod() if someBool is true and everytime recursiveMethod() is called, the value of i starts from 0 and goes on callingrecursiveMethod().

As mentionned in previous comment, simply putting a return statement at the end of the method does not guarantee you are achieving what you need

Upvotes: 0

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