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November 6th, 2006, 03:25 PM

derbys

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Java newbie help.

Hey, im in need of a little help with a little piece that i need to do and i dont especially get how to do it. What i want to do is write a method that takes two one-dimensional arrays of strings and determine whether or not both arrays contain the same words. For example, the following two arrays contain the same words:

cast static thread make void import

void make import cast thread static

Im struggling of how i would go about doing tis and if anyone has any ideas id be greatful.

Cheers.

November 6th, 2006, 05:32 PM

fizker

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The answer seems to be to just iterate through each array, and compare all elements to each other.

For example (I know, ugly complexity, but it gets the job done):

Code:

public void printDuplicates(String[] arr1, String[] arr2) {
    for(int i = 0; i < arr1.length; i++) {
        for(int j = 0; j < arr2.length; j++) {
            /* remember to use the right indexer, or you will get an indexOutOfBounds exception */
            if(arr1[i].equals(arr2[j])) {
                System.out.println("Duplicate found: "+arr1[i]);
            }
        }
    }
}

Here I print all the duplicates, but it should be simple to alter the code to do whatever you need

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November 7th, 2006, 03:38 PM

colton22

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if you get that error just use...
try-catch to alter and keep going

colton22

November 7th, 2006, 10:32 PM

daniel_g

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Added a count to fizker's code to see if all the word on arr1 are on arr2:

Code:

public void printDuplicates(String[] arr1, String[] arr2) {
    int count = 0;
    for(int i = 0; i < arr1.length; i++) {
        for(int j = 0; j < arr2.length; j++) {
            /* remember to use the right indexer, or you will get an indexOutOfBounds exception */
            if(arr1[i].equals(arr2[j])) {
                System.out.println("Duplicate found: "+arr1[i]);
                count++;
            }// end if
        }// end for
    }// end for
   if(count == arr1.length)
       System.out.println("All words on array1 are on array2");
}

December 28th, 2006, 01:29 PM

FUBAR

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to make the method more efficient, in terms of doing as little checking whenever possible, I'd approach it something like this...

Code:

public boolean matches(String[] arr1, String[] arr2) {
    if (arr1.length == arr2.length) {
        for (int i = 0; i < arr1.length; i++) {
            boolean foundMatch = false;
            for (int j = 0; j < arr2.length; j++) {
                if (arr1[i].equals(arr2[j])) {
                    foundMatch = true;
                    break;
                }
            }
            if (!foundMatch) {
                return false;
            }
        }
        return true;
    }
    return false;
}

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