Arrays not saving values JAVA

Question

hope you all are having a good day.

I've got a problem with my code, i am trying to save some values to an array, the array position gets moved by a counter, but when i try to save the values, it displays an error on the console.

this is the code.

        if(i<6){
        i++;
        jTxtEstrategia.setText(String.valueOf(i));


            A = (Math.random() * 8);
            B = (Math.random() * 8);
            C = (Math.random() * 8);
            D = (Math.random() * 8);

            jTxtA.setText(""+(int)A);
            jTxtB.setText(""+(int)B);
            jTxtC.setText(""+(int)C);
            jTxtD.setText(""+(int)D);



            int[] j = new int[i];
            int[] k = new int[i];
            int[] l = new int[i];
            int[] m = new int[i];

            j[i]=(int) A;
            k[i]=(int)B;
            l[i]=(int)C;
            m[i]=(int)D;

            System.out.println("Estrategia "+i+"\n Sucursal A: "+j[i]+"\n Sucursal B: "+k[i]+"Sucursal C: "+l[i]+"\n Sucursal C: "+m[i]);
    }else{
        jButtCalc.setEnabled(false);
    }

The objetive is to save those values to save some code and compare them later on.

I appreciate your time,

Regards (sorry for my bad english).

You should include the error you get on the console (Exception) in your question. See What is a stack trace, and how can I use it to debug my application errors? — user6073886
– user6073886, Commented Apr 19, 2017 at 18:01
int[] j = new int[i]; this creates a brand new array, so, you are writing over your previous value. — user180100
– user180100, Commented Apr 19, 2017 at 18:01
I suggest some reading: docs.oracle.com/javase/tutorial/java/nutsandbolts/arrays.html — user180100
– user180100, Commented Apr 19, 2017 at 18:02
Aside from writing over previous values by creating new arrays in each iteration, you're declaring each new array with length i and then trying to set the ith variable which isn't possible. For example, if you create an array with length 8 then it has indexes 0-7.. there is no 8th index. — mrogers
– mrogers, Commented Apr 19, 2017 at 18:03

radoh · Accepted Answer · 2017-04-19 18:26:10Z

1

I am assuming you are getting ArrayOutOfBounds exception?
Let's say value of i is 1. Then you are creating an array of size 1, but accessing its 2nd element, here:

            int[] j = new int[i];
...
            j[i]=(int) A;

You need to define the arrays before the loop/cycle/for/while with a correct number of elements. E.g.:

int[] j = new int[N]; // where N is 6, or some other number?...
 ...
while (...) {
  if(i<6){
    i++;
 ...

But ideally, you should define your loop in a more common way, like:

for (int i = 0; i < 6; i++) {
...

edited Apr 19, 2017 at 18:26

answered Apr 19, 2017 at 18:03

radoh

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4 Comments

Rodrigo RS Mahecha Over a year ago

that's why i made j, k, l and m, j is saving all values from a when generating their randoms while i is increasing.

Rodrigo RS Mahecha Over a year ago

Example, j is saving all values from A until i gets to the sixth iteration. k is saving all values from B until i gets to the sixth iteration, etc

radoh Over a year ago

@RodrigoRSMahecha I've fixed my answer according to your comments.

Rodrigo RS Mahecha Over a year ago

It Worked! Thanks a lot for ur help and ur time ^^ i appreciate it

B Gunasekara · Accepted Answer · 2017-04-19 18:35:22Z

in your code it create array objects again and again, And your array size grow up , so use ARRAYLIST it allow you to generate it's size. you have to use arrayListName.add(index,value) insted of arrayName[index] = value to add value into array list and to retrieve value you have to use arayListName.get(index) insted of using arrayName[index]

    ArrayList<Integer> j= new ArrayList<Integer>();
    ArrayList<Integer> k= new ArrayList<Integer>();
    ArrayList<Integer> l= new ArrayList<Integer>();
    ArrayList<Integer> m= new ArrayList<Integer>();

if(i<6){

        i++;
        jTxtEstrategia.setText(String.valueOf(i));


            A = (Math.random() * 8);
            B = (Math.random() * 8);
            C = (Math.random() * 8);
            D = (Math.random() * 8);

            jTxtA.setText(""+(int)A);
            jTxtB.setText(""+(int)B);
            jTxtC.setText(""+(int)C);
            jTxtD.setText(""+(int)D);



            j.add(i,(int)A);
            k.add(i,(int)B);
            l.add(i,(int)C);
            m.add(i,(int)D);

            System.out.println("Estrategia "+i+"\n Sucursal A: "+j.get(i)+"\n Sucursal B: "+k.get(i)+"Sucursal C: "+l.get(i)+"\n Sucursal C: "+m.get(i));
    }else{
        jButtCalc.setEnabled(false);
    }

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