Question

I am trying to figure out how to write a loop that will calculate the sum of elements in an array up to the current index. This is for part of a solution for calculating prefix averages.
I have included my method so far (including the pseudo-code I am trying to write).
I would appreciate any help offered!

// getAverages method populates the b array with the prefix averages
public void getAverages()                      
{
    // A prefix average is calculated by averaging all the numbers up to your current index.
    // b[i] is the average of a[0]…a[i], for 0 <= i <= n

    for (int i = 0; i < a.length; i++)
    {
        b[i] = the sum of all a indexes up to i divided by (i + 1)
    }

}

Answer 1

double sum = 0;
for (int i = 0; i < a.length; i++) {
    sum+=a[i];
    b[i] =sum/ (i + 1);
}

sum stores all the sum up to the current index. I hope it solves your problem.