Given a fixed-length integer array arr, duplicate each occurrence of zero, shifting the remaining elements to the right.

Sure, here is a Python solution for the problem:

def duplicateZeros(arr):
    i = 0
    while i < len(arr):
        if arr[i] == 0:
            arr.insert(i, 0)
            arr.pop()
            i += 1
        i += 1
    return arr

Here is a step-by-step explanation of the code:

1. We start by defining a function duplicateZeros that takes an array arr as an argument.

2. We initialize a counter i to 0. This counter will be used to iterate over the array.

3. We start a while loop that will continue as long as i is less than the length of the array.

4. Inside the loop, we check if the current element of the array (i.e., arr[i]) is 0.

5. If it is, we insert a 0 at the current index i using the insert method. This shifts all elements to the right.

6. Since the array is of fixed length, we need to remove the last element of the array to maintain the same length. We do this using the pop method.

7. We then increment i by 1 to skip the next 0 we just inserted.

8. If the current element is not 0, we simply increment i by 1 to move to the next element.

9. Finally, we return the modified array.