Question

I’m putting 1D Arrays in an Array List

ArrayList<int[]> pairs_ref = new ArrayList();
int[]singlePair_ref = new int [2];


singlePair_ref[0] = 15;
singlePair_ref[1] = 0;

pairs_ref.add(singlePair_ref);

return pairs_ref;

However, an test output on the console only shows Zeros, not the correct values

 pairs_ref = object_ref.methodFillsArrayListAsShownAbove();

 for (int t = 0;t<pairs_ref.size();t++){

        int[]array_ref = pairs_ref.get(t);
        System.out.println("Live: "+array_ref[0]+"  "+array_ref[1]);

    }//endfor

this Version brings the same result

 int[]array_ref = new int[2];
 for (int t = 0;t<pairs_ref.size();

 array_ref = pairs_ref.get(t);
        System.out.println("Live: "+array_ref[0]+"  "+array_ref[1]);
        System.out.println(pairs_ref.get(t));}

Why is this? Is it the putting or the getting of the variables of the ArrayList?
Thanks in Advance!
Daniel

Answer 1

Note that as of Java 5 your code can be simplified:

ArrayList<int[]> pairs_ref = new ArrayList<int[]>(); //note the use of generics in the parameter
int[] singlePair_ref = new int [2];
singlePair_ref[0] = 15;
singlePair_ref[1] = 0;

pairs_ref.add(singlePair_ref);

//simplification here
for (int[] arr : pairs_ref){
    System.out.println("Live: "+arr[0]+"  "+arr[1]);
}

This should work at your system.