collapse

  Write a static method collapse that takes an array
    of integers as an argument and that returns a new array that contains the
    result of collapsing the original list by replacing each successive pair of
    integers with the sum of the pair.  For example, if a variable called
    "list" stores this sequence of values:

	(7, 2, 8, 9, 4, 13, 7, 1, 9, 10)

    Then the following call:

        collapse(list);

    Should return a new array containing the following values:

	(9, 17, 17, 8, 19)

    The first pair from the original list is collapsed into 9 (7 + 2), the
    second pair is collapsed into 17 (8 + 9), the third pair is collapsed into
    17 (4 + 13) and so on.

    If the list stores an odd number of elements, the final element is not
    collapsed.  For example, if the list had been:

	(1, 2, 3, 4, 5)

   Then the call on collapse would produce the following list:

	(3, 7, 5)

    with the 5 at the end of the list unchanged.  Keep in mind that your method
    is to return a new array of appropriate length that you construct.  Your
    method should not change the array that is passed as a parameter.

    Write your solution to collapse below.