How does a double for loop work?

Question

Java

Each element of the two-dimensional array array is sequentially assigned the elements of the one-dimensional array row, in which all elements are sequentially assigned to the cell variable. It is not clear how this works, in the inner for everything is written in a row, but why then the outer for?

public List<Integer> toList(int[][] array) {
  List<Integer> list = new ArrayList<>();
        for (int[] row : array) {
            for (int cell : row) {
                list.add(cell);
            }
        }
    return list;
}

Answer 1

The outer forone is needed in order to go through all the arrays inside array.
That is, at the first iteration of the outer loop, listall elements from the first array will be added, at the second iteration from the second, and so on.