Insert item to array

I have 3 arrays which contains 5 elements each (max size is 5). What I wanted to do is to insert an item, e.g, to position 7. The end result is the item should be placed in 2nd array at index 2 and a 4th array is then created with 1 element (from last item of 3rd array).

                                result
array1                          array1
    - item1 (position 0)            - item1 (position 0)
    - item2 (position 1)            - item2 (position 1)
    - item3 (position 2)            - item3 (position 2)
    - item4 (position 3)            - item4 (position 3)
    - item5 (position 4)            - item5 (position 4)
array2                          array2
    - item1 (position 5)            - item1 (position 5)
    - item2 (position 6)            - item2 (position 6)
    - item3 (position 7)            - item3 (position 7) -> new_item
    - item4 (position 8)            - item4 (position 8)
    - item5 (position 9)            - item5 (position 9)
array3                          array3
    - item1 (position 10)           - item1 (position 10)
    - item2 (position 11)           - item2 (position 11)
    - item3 (position 12)           - item3 (position 12)
    - item4 (position 13)           - item4 (position 13)
    - item5 (position 14)           - item5 (position 14)
                                array4
                                    - item1 (position 15)

And, if wanted to get the item at position 12, then the result should be item3 of array3.

How can I do this in c++?