Exercise 18

The reverse of

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
    [5] => 6
)

Array
(
    [0] => 6
    [1] => 5
    [2] => 4
    [3] => 3
    [4] => 2
    [5] => 1
)

The reverse of

Array
(
    [0] => abc
    [1] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
        )

    [2] => 7.8
)

Array
(
    [0] => 7.8
    [1] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
        )

    [2] => abc
)