1. Write a method that takes an array of ints (any length)
and stores 2n+1 at index n for each element of the array.

2. Write a method that takes an ArrayList of Integers
and stores 2n+1 at index n for each element of the ArrayList.

3. Write a method that takes an array of ints and prints
the sum of its elements.

4. Write a method that takes an ArrayList of Integers and
prints the sum of its elements.