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  1. #1
    counterfox is offline Member
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    Default How to find out if part of an array is empty

    Say we have a simple array like this:

    class test{

    public static void main(String[] args){
    int arr[] = new int[10];
    for(int i=0;i<4;i++){
    arr[i] = i;
    for(int j=0;j<arr.length;j++){

    where the array has only a few parts of it given values. Is there any way to know in a sort of test what parts of the array are empty.

    Because when I run this is cmd, i get 0 in each of the empty parts but I'm thinking also from that program position 0 also contains "0" as was done in the for loop.

    thanks in advance

  2. #2
    JosAH's Avatar
    JosAH is offline Moderator
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    Voorschoten, the Netherlands
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    An array never contains 'empty' elements because when you create one all bits of all elements are set to zero. For an array of primitives this means that all elements contain a form of 0, 0L, 0.0 etc. For an array of objects all elements contain null.

    You have to find a 'sentinel' value, i.e. a value that you normally don't use and indicates an 'empty' value. Of course the value isn't really empty but it denotes an unused element. Also, have a look at the ArrayList class, it only stores elements you have actually stored in there.

    kind regards,

    Last edited by JosAH; 10-13-2010 at 06:21 PM.

  3. #3
    rohitjava is offline Member
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