How divide all items in an array by a double?

Question

I am a complete beginner at this and I have a little problem with an array. The point of this program is to calculate the normalization of a vector. The first part just calculates the length of the array into the int called sum and then I want to divide all the items in the array v with this sum. normal[] = v[a]/sum; this line is clearly the issue, but how should I do this??

public static double[] normalized(double[] v){

    double sum = 0;

    for(int counter = 0; counter < v.length; counter++){
        sum += Math.pow(v[counter], 2);
    }
        sum = Math.sqrt(sum);
        double[] normal;
    for(int a = 0; a < v.length; a++){      
        normal[] = v[a]/sum;
    }
return normal;
}

Answer 1

All you need to do is specify an index for your normal array like so, and make sure to initialize normal:

double[] normal = new double[v.length];
for(int a = 0; a < v.length; a++)
{
  normal[a] = v[a]/sum;
}

Assuming that your sum is correct. I believe this should work.

Answer 2

There are two problems:

• You're not initializing normal (or indeed creating an array to populate)
• You're not specifying which element you're trying to set within normal

So you want:

double[] normal = new double[v.length];
for(int a = 0; a < v.length; a++) {
  normal[a] = v[a] / sum;
}
return normal;