I've been trying to work this out:

Say I have an array:

```
int[] n = {0, 0, -1, 1, 0, 1, 1, -1, 1};

```

I need to be able to sort through the array and if there is a zero with a non zero preceding it, then they should be swapped.

For example: `0, 0, -1, 1, 0, 1, 1, -1, 1`

will become: `0, 0, -1, 0, 1, 1, 1, -1, 1`

I have been trying to do it using a `for` loop and `if` statements with no luck. Any tips?